# Outsided A/C Unit Ambient Temperature Question???



## etsherman (Aug 2, 2011)

I live in Houston, TX with extreme hot days (100 degrees +) and trying to decide would it be helpful to shade my outside air conditioner unit. It sits on the west side of my home and is exposed to direct sun light from 11:30 am until the sun goes down late in the evenings. We run the inside thermostat between 74 and 76 degrees because someone is at home during the day. My unit (14 year old Ruud 5 ton) cools well but I noticed it runs a long time on hot days. My kWh is running around 2,800 for these hot months. I am trying to get it down to like 2,000. Raising the temp to 78 in the house becomes uncomfortable to be honest. 

My thinking is the outside a/c unit is like your car parked outside in direct sunlight ... it gets extremely hot compared to the same car that's parked outside but under a carport and not in direct sunlight. I took some temperature readings and the ambient temperature around my unit mid-day is around 125 degrees with the air temperature exhausted from the unit around 130 degree. I'm sure with this unit shaded ... that ambient temperature could drop to about 105 degrees which should make the unit run more efficiently. I'm not a HVAC tech. but it just seems logical.

Would shading this a/c unit be worth it in your opinion or am I just wasting time and a little money???

The other question that I have is, I took a temperature reading of my neighbors outside a/c unit since it sits in the same place as mine (west side of the house in direct sunlight) and found the temperature of the exhaust air to be around 100 degrees ... that's 20 degrees lower than mine at the same time of day and it doesn't appear to run as long as mine does when it cycles on. There unit is a new 5 ton Goodman that was installed a few months ago.

If both units are extracting heat from the insides of the homes sitting next to each other and blowing it into the outside air ... why would there be a 20 degree difference in the exhausted air??? That's what I'm trying to figure out ... is the new unit that much more efficient at cooling down the Freon and should I be looking at a more efficient unit although the current one is working?


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## user_12345a (Nov 23, 2014)

Waste of time and money. Shading can actual block airflow and cause re-circulation.

It's not a like a car in the sun because it moves a lot of air through the coil.

Your thermometer is picking up the radiant heat from the sun, but it's the air temperature going into the coil that matters.

Just keep the coil clean and the area around the unit clear. Don't put anything around or above the unit including plants, shades, etc.


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## slwtypmark (May 17, 2018)

Yes, if the unit sits in the Hot afternoon sun, so be it, can't do anything about it short of Relocation to the opposite side of your home!..and we know you don't want to do that!


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## etsherman (Aug 2, 2011)

Thanks for the replies ... "Shading can actually block airflow and cause re-circulation". Yes, this is what I was concerned about. 

Still trying to figure out why the exhaust air from two different units taken at the same time of day and exposed to the same sunlight can have a 20 degree difference in temperatures.


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## user_12345a (Nov 23, 2014)

Different units can have different exhaust air temps. So many things that influence that - different condenser cfm vs capacity which can vary even for the same model line. 

Units of different efficiency ratings -> the higher the efficiency, the less energy is consumed by compressor which gets absorbed by refrigerant and ejected in form of heat.

One coil can be dirtier than the other too. 

Airflow across both indoor coils relative to capacity. More airflow -> removes slightly more heat and the exhaust is a tad warmer.

etc.

Don't obsess much over this.


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## thekux (Jul 30, 2018)

Living in Houston 100 degree day it just might be a price you have to pay. The only thing I could suggest is measure the air temperature going into the unit on the hot days. See if it's about the same as the ambient. I don't see anything that would be greatly increasing the temperature of the air going into it. The sun's going to bounce off that brick and it will reflect heat I'm sure. If the air temperature is much greater than the ambient going into your unit because of the surroundings like the brick then it will create a bigger load on your unit and might reduce capacity. The unit looks like it's hugging the house I can't tell how much clearance you have from the wall to your unit I'm hoping you have at least 12 in


On some commercial buildings they have had problems with their AC after new Roofing jobs because it reflects so much heat off the roof it greatly increases that air temperature surrounding the equipment causing problems. Don't think that's going to be a problem here but it's worth measuring your air temperature going into it it should match whatever that outdoor air temperature or be very close to it
Sent from my SM-J700T using Tapatalk


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## beenthere (Oct 11, 2008)

How old is your AC. It may be a much lower efficiency unit than your neighbors. Is your neighbor’s a 2 stage unit that was running in first stage.


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## etsherman (Aug 2, 2011)

Ok, I did not shade the a/c unit but I did add a mister system. I had been debating about these for some time and decided to give it a try as the mist would not only cool the coils and fins but also cool the external cabinet. I can truly say that it works. The first full day of running it my kWh usage dropped in half (same temp outside and inside thermostat set on 75 degrees)!!! My utility company tracks your daily usage and makes that data available on the web.

There are pros and cons regarding using a misting system on your a/c unit with most concern being the calcium buildup. My water is not extremely hard and I have a sprinkler system that has basically sprayed that unit for the last 14 years with 0 calcium on the fins. I included a calcium filter on the water line and will watch closely for any type of buildup on the fins.

It's just hard to dismiss those types of drops in power usage by simply adding a mist to the air the unit is sucking in. Kind of makes you wonder why a/c manufactures don't make liquid cooled units for extremely hot climates!!!


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## thekux (Jul 30, 2018)

The outdoor unit should be able to handle that. Maybe the sun reflecting off the brick is making it quite a bit hotter around the unit on those really hot days

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## SeniorSitizen (Sep 10, 2012)

The cabinet can be cooled with shade but not in the configuration in the original post.


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## thekux (Jul 30, 2018)

I don't know if anybody ask did you check your outdoor coil and try to wash it with light pressure? You might just have a dirty outdoor coil possibly. It doesn't hurt to wash it out

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## etsherman (Aug 2, 2011)

thekux said:


> The outdoor unit should be able to handle that. Maybe the sun reflecting off the brick is making it quite a bit hotter around the unit on those really hot days
> 
> Sent from my SM-J700T using Tapatalk


Yes, that's correct ... That is the west side of the property and those bricks and a/c unit starts heating up from about 11:00 am to way after the sun goes down. Those bricks act like a radiator to be honest. That unit should have been placed in the back yard which is the north side of the property and does not get a direct shot of hot sun for an extended period of time like the west side does.

Also, I clean that unit with the hose monthly. The coil and fins look like the day it was installed ... shiny silver looking.


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## etsherman (Aug 2, 2011)

SeniorSitizen said:


> The cabinet can be cooled with shade but not in the configuration in the original post.


How would you recommend shading it without using something like an awning?


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## BayouRunner (Feb 5, 2016)

Just checking, did you remove the cover and clean the coils inside the cover as well? A lot of homeowners don’t realize there is coils inside as well.


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## etsherman (Aug 2, 2011)

Here's the video ... this really works ... and I built the misting system for $50!!!


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## thekux (Jul 30, 2018)

etsherman said:


> Yes, that's correct ... That is the west side of the property and those bricks and a/c unit starts heating up from about 11:00 am to way after the sun goes down. Those bricks act like a radiator to be honest. That unit should have been placed in the back yard which is the north side of the property and does not get a direct shot of hot sun for an extended period of time like the west side does.
> 
> Also, I clean that unit with the hose monthly. The coil and fins look like the day it was installed ... shiny silver looking.


I have read a few articles about roofing materials that have caused a lot of disastrous results with rooftop AC units on commercial buildings. The new roof is reflecting so much heat that it will increase the ambient temperature around the the units by 20 to 30 degrees causing lots of trouble on really hot days. Is your unit cooling better since you put on the misting line?

Sent from my SM-J700T using Tapatalk


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## supers05 (May 23, 2015)

Direct sunlight has little effect on condensating temperatures. (Pressure that it's running at) 

The water on the coil will cause galvanic corrosion between the copper tubes and aluminum fins. (all aluminum coils don't have that problem.) 

Cheers!


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## user_12345a (Nov 23, 2014)

Misters are horrible for condenser coils, the water has minerals in it that get left behind and block it up. Not only a corrosion issue.


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## etsherman (Aug 2, 2011)

thekux said:


> I have read a few articles about roofing materials that have caused a lot of disastrous results with rooftop AC units on commercial buildings. The new roof is reflecting so much heat that it will increase the ambient temperature around the the units by 20 to 30 degrees causing lots of trouble on really hot days. Is your unit cooling better since you put on the misting line?
> 
> Sent from my SM-J700T using Tapatalk


It was cooling properly before the misting kit ... I was just running a long time to get it done. However I did notice the air coming out the vents inside the house is much colder and the unit does not run for long periods of time even during the hottest part of the day.


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## etsherman (Aug 2, 2011)

supers05 said:


> Direct sunlight has little effect on condensating temperatures. (Pressure that it's running at)
> 
> The water on the coil will cause galvanic corrosion between the copper tubes and aluminum fins. (all aluminum coils don't have that problem.)
> 
> Cheers!


Notice the grass is well hydrated even though it bakes in 100 degree temps from about 10:00 am to about 7:00 pm. There is a sprinkler line that has dumped that same water on that unit for the last 14 years ... no sign of corrosion or calcium build up on the coil and the fins or even the cabinet.

That was my concern at first until I thought about it.


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## etsherman (Aug 2, 2011)

user_12345a said:


> Misters are horrible for condenser coils, the water has minerals in it that get left behind and block it up. Not only a corrosion issue.


Notice the grass is well hydrated even though it bakes in 100 degree temps from about 10:00 am to about 7:00 pm. There is a sprinkler line that has dumped that same water on that unit for the last 14 years ... no sign of corrosion or calcium build up on the coil and the fins or even the cabinet.

That was my concern at first until I thought about it.


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## digitalplumber (Jul 8, 2011)

I live in Houston, 2 4 ton units. House is 3600, 1800 up and down. Upstairs nit is set on 80 down is set on 75. AC's are on east side, no issues with cycling or cooling.

In seeing you current unit, it appears to possibly be a recent install or not very old? 

Have you had it checked? Whats you insulation like?


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## user_12345a (Nov 23, 2014)

There's a huge difference between getting wet by a sprinkler even a few times a week and having mist being pulled into the coil, wetting it and having it evaporate.

Have you ever dealt with a drum humidifier? They load with mineral deposits, the sponge get really hard and stops being able to pick up water after a few months.

The misters can also reduce the refrigerant pressure too much and cause issues feeding the coil.

If you want to wreck your unit to save a few bucks a month, not my problem.


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## etsherman (Aug 2, 2011)

BayouRunner said:


> Just checking, did you remove the cover and clean the coils inside the cover as well? A lot of homeowners don’t realize there is coils inside as well.
> 
> 
> Sent from my iPad using Tapatalk


Thanks, yes I did.


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## thekux (Jul 30, 2018)

I was wondering if you ever check the air temperature around your unit. I don't see any harm on your unit from the misters. You might want to check it once in a while I don't think you're going to have to worry about minerals. They have to use misters in Las Vegas

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## etsherman (Aug 2, 2011)

digitalplumber said:


> I live in Houston, 2 4 ton units. House is 3600, 1800 up and down. Upstairs nit is set on 80 down is set on 75. AC's are on east side, no issues with cycling or cooling.
> 
> In seeing you current unit, it appears to possibly be a recent install or not very old?
> 
> Have you had it checked? Whats you insulation like?


I live in Houston as well ... Sugar Land area. That's a 5 ton RUUD unit and was installed in 2004 making it 14 years old. I've never had any problems and it was recently inspected by my HVAC tech a few months ago. He is the original installer of the a/c unit as well as matching inside coil back in 2004. Good unit and no problems with it mechanically in all those years. The unit was cooling properly before the misting kit, it's just on those extremely hot days baking in that sun on the west side of the property the unit was working hard and long to get the job done. It pushed my monthly kWh usage up to over 3,000 kWh. Normally that's around 1,500 kWh in a month.


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## supers05 (May 23, 2015)

etsherman said:


> Notice the grass is well hydrated even though it bakes in 100 degree temps from about 10:00 am to about 7:00 pm. There is a sprinkler line that has dumped that same water on that unit for the last 14 years ... no sign of corrosion or calcium build up on the coil and the fins or even the cabinet.
> 
> That was my concern at first until I thought about it.


The corrosion is difficult to see. It causes the fins to separate from the tubes. It would explain your higher temps that you read on the coil. Unless the sprinkler is right next to the unit, the effect would be highly diminished. 

Cheers!


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## etsherman (Aug 2, 2011)

thekux said:


> I was wondering if you ever check the air temperature around your unit. I don't see any harm on your unit from the misters. You might want to check it once in a while I don't think you're going to have to worry about minerals. They have to use misters in Las Vegas
> 
> Sent from my SM-J700T using Tapatalk


Oh yes, that's why I decided to do something about it. Before the misters ... 3:00 pm the temp of the exhaust air coming out the top of the unit was 130 degrees. After the mister were running I took the temperature of the exhaust air at the same time 3:00 pm with the same direct sunlight ant it read 78 degrees!!!. Numbers don't lie!!!! $$$$$$$$$$$ for me!!!


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## thekux (Jul 30, 2018)

etsherman said:


> Oh yes, that's why I decided to do something about it. Before the misters ... 3:00 pm the temp of the exhaust air coming out the top of the unit was 130 degrees. After the mister were running I took the temperature of the exhaust air at the same time 3:00 pm with the same direct sunlight ant it read 78 degrees!!!. Numbers don't lie!!!! $$$$$$$$$$$ for me!!!


Not the exhaust that sounds about right to me I was wondering what the temperature was going into it. If you had a hundred degrees going into it and 130 degrees coming out that's about right. I was wondering if the air going into it is actually warmer then the recorded air temperature . example if it is 100 degrees outside, and you go to your unit and they are going into it is 110 115 then you would know that the brick is causing the Ambient Air Temperature around your AC unit to be warmer from the Brick.

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## u3b3rg33k (Jul 17, 2018)

I hate to say it but unless you have a coastal unit, people are right to be concerned about the life of your condenser. also you have way more mister nozzles on it than you need. that much water and you could probably do city water dump through a water cooled condenser rather than wetting a dry coil.

I would recommend you only run it on the hottest days, and leave it off the rest of the time.


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## user_12345a (Nov 23, 2014)

Like nest thermostats, 3m allergen filters, wifi fake zoning register dampers, booster fans, misters should never be used. Leave them off all the time.


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## SeniorSitizen (Sep 10, 2012)

etsherman said:


> How would you recommend shading it without using something like an awning?


The awning is fine but the location makes it way too restrictive. If it were to be moved out to the west free standing and at approximately that same angle with the high side *not *over the unit so the air flow isn't inhibited that would make shade without inhibiting air flow.


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## beenthere (Oct 11, 2008)

etsherman said:


> Kind of makes you wonder why a/c manufactures don't make liquid cooled units for extremely hot climates!!!



Actually, they do make water cooled units/condensers. 



FHP, and Bosch are the first ones to come to mind.


Do you have 2 water meters? One for water for the house, and one for the sprinkler system?


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## u3b3rg33k (Jul 17, 2018)

beenthere said:


> Actually, they do make water cooled units/condensers.
> 
> 
> 
> ...


plenty of cooling towers down south. hotels have em - all the PTACs are water cooled condensers. probably makes the maintenance way easier, cause someone actually maintains the cooling tower (no one cleans a PTAC condenser - ever). 

here's a little one


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## beenthere (Oct 11, 2008)

u3b3rg33k said:


> plenty of cooling towers down south. hotels have em - all the PTACs are water cooled condensers. probably makes the maintenance way easier, cause someone actually maintains the cooling tower (no one cleans a PTAC condenser - ever).
> 
> here's a little one



Cooling towers with 400 HP pumps are easier to maintain than one with a little 40 HP pump. Just takes a little more time when cleaning them.


But its a bugger to change out a fan motor on them. Which fortunately doesn't happen often.


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## supers05 (May 23, 2015)

u3b3rg33k said:


> plenty of cooling towers down south. hotels have em - all the PTACs are water cooled condensers. probably makes the maintenance way easier, cause someone actually maintains the cooling tower (no one cleans a PTAC condenser - ever).
> 
> here's a little one


That certainly looks better then the exposed cooling tower would be. Here they hide them inside the building or in the parking garage. 

Cheers!


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## supers05 (May 23, 2015)

beenthere said:


> Cooling towers with 400 HP pumps are easier to maintain than one with a little 40 HP pump. Just takes a little more time when cleaning them.
> 
> 
> But its a bugger to change out a fan motor on them. Which fortunately doesn't happen often.


lol. I don't have to clean cooling Towers very often as that's a job for another company. However, i do maintain the pumps. Get down to 20HP and i don't need a chain fall, or forklift just to move it. [emoji23] 

OP: let us know how much your water bill increases on the next few bills. 

Cheers!


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## etsherman (Aug 2, 2011)

u3b3rg33k said:


> I hate to say it but unless you have a coastal unit, people are right to be concerned about the life of your condenser. also you have way more mister nozzles on it than you need. that much water and you could probably do city water dump through a water cooled condenser rather than wetting a dry coil.
> 
> I would recommend you only run it on the hottest days, and leave it off the rest of the time.


I am still adjusting it to see what works best. If need be I can open just one mister on the three sides.


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## etsherman (Aug 2, 2011)

beenthere said:


> Actually, they do make water cooled units/condensers.
> 
> 
> 
> ...


No, just one water meter. 1 inch sprinkler line comes off of the main line going into the house next to the meter.


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## etsherman (Aug 2, 2011)

supers05 said:


> lol. I don't have to clean cooling Towers very often as that's a job for another company. However, i do maintain the pumps. Get down to 20HP and i don't need a chain fall, or forklift just to move it. [emoji23]
> 
> OP: let us know how much your water bill increases on the next few bills.
> 
> Cheers!


Will do ... I have the misters adjusted to a very fine mist/fog ... pretty much like steam to be honest. I expect the water usage to be minimal but will keep an eye on it as well. See close up picture.


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## etsherman (Aug 2, 2011)

thekux said:


> Not the exhaust that sounds about right to me I was wondering what the temperature was going into it. If you had a hundred degrees going into it and 130 degrees coming out that's about right. I was wondering if the air going into it is actually warmer then the recorded air temperature . example if it is 100 degrees outside, and you go to your unit and they are going into it is 110 115 then you would know that the brick is causing the Ambient Air Temperature around your AC unit to be warmer from the Brick.
> 
> Sent from my SM-J700T using Tapatalk


Ok, now I understand what you are asking. Yes on Sunday I took several temperature readings. The recorded outside temp was around 99 degrees and when I took a temp reading at the intake on the a/c it was around 105 degrees.


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## digitalplumber (Jul 8, 2011)

etsherman said:


> I live in Houston as well ... Sugar Land area. That's a 5 ton RUUD unit and was installed in 2004 making it 14 years old. I've never had any problems and it was recently inspected by my HVAC tech a few months ago. He is the original installer of the a/c unit as well as matching inside coil back in 2004. Good unit and no problems with it mechanically in all those years. The unit was cooling properly before the misting kit, it's just on those extremely hot days baking in that sun on the west side of the property the unit was working hard and long to get the job done. It pushed my monthly kWh usage up to over 3,000 kWh. Normally that's around 1,500 kWh in a month.



How big is your house?


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## etsherman (Aug 2, 2011)

digitalplumber said:


> How big is your house?


2400 sq ft house.


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## digitalplumber (Jul 8, 2011)

etsherman said:


> 2400 sq ft house.


That unit should more than cool that home, IMO.

Whats your insulation like? 

Do you have tech sheild?

You state nothing about the furnace?blower unit, was it also installed in 2004, with the coil and condenser?? 

My 2 4 Tons are Rheem and were installed in 98.


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## supers05 (May 23, 2015)

etsherman said:


> Ok, now I understand what you are asking. Yes on Sunday I took several temperature readings. The recorded outside temp was around 99 degrees and when I took a temp reading at the intake on the a/c it was around 105 degrees.


Thermometer or IR gun? A shaded thermometer or probe is the only way to accurately measure the air temp. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Thermometer or IR gun? A shaded thermometer or probe is the only way to accurately measure the air temp.
> 
> Cheers!


IR Gun.


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## supers05 (May 23, 2015)

etsherman said:


> IR Gun.


Then you were measuring the surface temp. The paneling is heated by the sun, the coil is heated by the refrigerant. Grass is cooled by evaporation. All of which is not useful in this case. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> IR Gun.



Not accurate enough for temps in general, and not able to check actual air temps.


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## etsherman (Aug 2, 2011)

digitalplumber said:


> That unit should more than cool that home, IMO.
> 
> Whats your insulation like?
> 
> ...


Furnace and blower was replaced 8 months ago. The HVAC system is mechanically sound as well as the insides of the home. The original question was focused on does lowering the ambient temperature around the outside unit helps it to work more efficiently since it sits in direct sunlight on the west side of the property for a good portion of the day. I've found the answer to that being yes.


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## supers05 (May 23, 2015)

etsherman said:


> Furnace and blower was replaced 8 months ago. The HVAC system is mechanically sound as well as the insides of the home. The original question was focused on does lowering the ambient temperature around the outside unit helps it to work more efficiently since it sits in direct sunlight on the west side of the property for a good portion of the day. I've found the answer to that being yes.


Lowering ambient temps does increase efficiency. So it can be more efficient at night, as long as you still have solid liquid hitting the metering device. Because of the design of these units, they cannot tolerate ambients too low. I don't think you'll have that problem in your location though. 

Some people heat their pool or hot water with their AC. It has the same effect as your misters. You just have to like a really warm pool. 

Cheers!


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## etsherman (Aug 2, 2011)

Here is what got me thinking about ambient temps and was the reason for the original question. I have a air conditioned/heated dog house which is fully insulated (roof, walls and floor). Having two active Jack Russell Terriers staying inside was not an option (they chew, tear and bite everything in sight). Therefore I decided to give them their own space and they can do whatever they want to without being fussed at all the time. 

I noticed during the hottest portion of the day with recorded temps at 100+ degrees, that a/c unit may cycle once every hour lasting about 2 minutes each time. The inside thermostat is set a 85 degrees as pets don't need cold air to be comfortable ... the 20 degree difference between outside and inside that house makes all the difference for them. Since the a/c unit has a shade over it and it also gets some shade from the surrounding tree ... the unit itself never gets heated up. The surrounding air maybe at 100 degrees but the mechanical unit (cabinet, coil, fins, fan, etc.) never gets that hot. When the unit does turn on it just seems to work very efficiently because the machine is starting up cool. 

This is why I started thinking about shading my house a/c unit which sits there in the 100 degree sun baking all day long. If you keep the equipment cool as well as cool the ambient temp around the unit it just seems logical that the equipment will perform much more efficiently thus saving you $$$ in energy usage. That's my theory and I'm not a HVAC tech and their are many other variables that can impact how well a/c's function but for me down here in this HOT Houston climate ... I can truly say that the misters are making that equipment work a lot more efficiently and shading it can only increase that efficiency. Just my findings. Thanks all for your input.


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## beenthere (Oct 11, 2008)

If the air surrounding the dog house A/C gets to 100. Then the condenser does get that hot.


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## Dave Sal (Dec 20, 2012)

Looks like you might need a few more soffit vents which would help cool off your attic. Have you ever stuck a thermometer in the attic during the day to see how hot it gets? With adequate attic ventilation the temps should be slightly above the ambient outside temperature, maybe a bit more in direct sunlight.


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## etsherman (Aug 2, 2011)

Dave Sal said:


> Looks like you might need a few more soffit vents which would help cool off your attic. Have you ever stuck a thermometer in the attic during the day to see how hot it gets? With adequate attic ventilation the temps should be slightly above the ambient outside temperature, maybe a bit more in direct sunlight.


Attic is ok ... I have ridge vents as well as to large turbine vents.


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## etsherman (Aug 2, 2011)

beenthere said:


> If the air surrounding the dog house A/C gets to 100. Then the condenser does get that hot.


True but that's the overall objective ... don't let the air around the a/c get that hot using shade and cooling it with water misters.


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## beenthere (Oct 11, 2008)

Water misters have been around for 20 or so years. Majority of people have had problems due to them. So hopefully, your not gonna be one of the people that has problems.


But the dog house condenser still gets as hot as the outside air, shade or no shade. Since you don't have a mister on it.


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## digitalplumber (Jul 8, 2011)

etsherman said:


> Furnace and blower was replaced 8 months ago. The HVAC system is mechanically sound as well as the insides of the home. The original question was focused on does lowering the ambient temperature around the outside unit helps it to work more efficiently since it sits in direct sunlight on the west side of the property for a good portion of the day. I've found the answer to that being yes.



Yes I understand what your original question was. The system you have, if correctly matched, should more than amply cool your home even on 100 days in Houston. 

But, I think you came here trying to justify the use of the mister, so good luck!


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## etsherman (Aug 2, 2011)

beenthere said:


> Water misters have been around for 20 or so years. Majority of people have had problems due to them. So hopefully, your not gonna be one of the people that has problems.
> 
> 
> But the dog house condenser still gets as hot as the outside air, shade or no shade. Since you don't have a mister on it.


I have to disagree with your comment above. Please review the two pictures below. 

Temp Read Time = 4:45 pm Central time and it is showing 104 degrees outside temperature. I immediately took a reading 12 inches from the dog house a/c cabinet and it shows 89.8 degrees. This proves that shading the a/c does lower the overall temperature of the unit. Same as if you parked two cars side by side with one shaded. One is going to be cooler even though the outside temp for both cars is the same.


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## supers05 (May 23, 2015)

etsherman said:


> I have to disagree with your comment above. Please review the two pictures below.
> 
> Temp Read Time = 4:45 pm Central time and it is showing 104 degrees outside temperature. I immediately took a reading 12 inches from the dog house a/c cabinet and it shows 89.8 degrees. This proves that shading the a/c does lower the overall temperature of the unit. Same as if you parked two cars side by side with one shaded. One is going to be cooler even though the outside temp for both cars is the same.


The pressures and temps of ACs are highly dependent on outdoor air temp. Solar pickup is extremely low. The dog house / your house themselves will pickup solar energy, but not the AC. They are designed that way. That IR gun is not measuring air temp. Don't forget that the grass is evaporating water, just like the misters. 

PS. Some lucky dogs!

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> I have to disagree with your comment above. Please review the two pictures below.
> 
> Temp Read Time = 4:45 pm Central time and it is showing 104 degrees outside temperature. I immediately took a reading 12 inches from the dog house a/c cabinet and it shows 89.8 degrees. This proves that shading the a/c does lower the overall temperature of the unit. Same as if you parked two cars side by side with one shaded. One is going to be cooler even though the outside temp for both cars is the same.



In order for the temp at the dog house to be 89.9 degrees, that is what the air temp has to be.


Your thermometer is showing you the temp of the radiant heat, not the air temp.


Next, your IR is not accurate.


Anytime you taker a temp reading in the sunlight, you are also reading radiant heat. Which is why we shield our temp sensors when taking the air temp entering a condenser.


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## HannesAlven (Feb 17, 2018)

I am not a HVAC expert but from a conceptual point of view, what you're proposing makes sense. Cooling down the area surrounding the AC compressor can increase the efficiency of your AC. The AC basically extracts unwanted heat from the interior of your house and rejects it outside which is at a considerably higher temperature. But in order to carry out this heat rejection process, the temperature of the refrigerant has to be raised (via the compressor) to a value above that of the outside environment. On days that are hotter, temperature difference between the refrigerant and the outside temperature will be smaller and so the heat transfer won't be as efficient.


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## beenthere (Oct 11, 2008)

HannesAlven said:


> On days that are hotter, temperature difference between the refrigerant and the outside temperature will be smaller and so the heat transfer won't be as efficient.



No, it is not smaller/less. Or else the A/C wouldn't work.


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## user_12345a (Nov 23, 2014)

The head pressure goes up as it gets hotter and the boiling point goes too.

The compressor amp draw goes up, overall cooling capacity drops a tad bit.


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## etsherman (Aug 2, 2011)

I understand but at the end of the day ... shading your a/c and water misters can significantly reduce your power consumption ... I feel pretty sure about that. 

I'm not a HVAC tech but I am a numbers tech (accounting/finance) and numbers don't lie. My power company provides a daily usage summary to its customers via your web account. Looking at at the graph my daily power consumption dropped by 44% running the a/c with the misters on and same or pretty close to the same outside temperatures. That's a lot of savings!!!

Look at the drop in power consumption between Sunday the 29th and Monday the 30th ... keep in mind I installed the misters at 3:00 pm on Monday the 30th. The drop was almost instant!!!

Again, thanks all for you input.


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## etsherman (Aug 2, 2011)

HannesAlven said:


> I am not a HVAC expert but from a conceptual point of view, what you're proposing makes sense. Cooling down the area surrounding the AC compressor can increase the efficiency of your AC. The AC basically extracts unwanted heat from the interior of your house and rejects it outside which is at a considerably higher temperature. But in order to carry out this heat rejection process, the temperature of the refrigerant has to be raised (via the compressor) to a value above that of the outside environment. On days that are hotter, temperature difference between the refrigerant and the outside temperature will be smaller and so the heat transfer won't be as efficient.


Exactly ... The misters and shading brings the temperature of the machine and surrounding air down below the refrigerant carrying the hot air it is trying to expel. It makes the machine work more efficiently at doing that which uses less electricity.


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## user_12345a (Nov 23, 2014)

There are often other factors at play - cooking, dryer use, electric hot water use, how sunny it is.

It's highly unlikely your savings are all due to misters. You also have to look at water use.

Your savings may be required to replace the a/c after the coils gets wrecked.

This is something to experiment with a 20+ year old trashy unit, not a middle aged rheem. What you have is very good, with a scroll compressor and controls in a separate compartment. 

They don't build 'em like that any more so it would be a real shame to ruin such a nice unit.


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## supers05 (May 23, 2015)

etsherman said:


> Exactly ... The misters and shading brings the temperature of the machine and surrounding air down below the refrigerant carrying the hot air it is trying to expel. It makes the machine work more efficiently at doing that which uses less electricity.


It's less the shade of the back yard and more of the larger surface area of grass. The fewer Brick walls/ pavement/concrete floors warming the air helps too. 

Cheers!


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## etsherman (Aug 2, 2011)

user_12345a said:


> There are often other factors at play - cooking, dryer use, electric hot water use, how sunny it is.
> 
> It's highly unlikely your savings are all due to misters. You also have to look at water use.
> 
> ...


I understand and appreciate your comments. It is a good unit ... Installed it in 2004 and never had any problems with it, not one. Never had to add refrigerant to it. I replaced the cooling fan on it a few months ago but that's not bad for 14 years of dependable service. 

I will keep an eye on the coils plus my whole house is on a high end filtered water system. The calcium build up is really not an issue for me. I built this house in 1985 making it 33 years old. The picture below is the original shower doors that were installed in 1985 ... no calcium build up in the shower or on the doors. I do hit those doors with RainX once a year though!!!


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## beenthere (Oct 11, 2008)

etsherman said:


> I understand but at the end of the day ... shading your a/c and water misters can significantly reduce your power consumption ... I feel pretty sure about that.
> 
> I'm not a HVAC tech but I am a numbers tech (accounting/finance) and numbers don't lie. My power company provides a daily usage summary to its customers via your web account. Looking at at the graph my daily power consumption dropped by 44% running the a/c with the misters on and same or pretty close to the same outside temperatures. That's a lot of savings!!!
> 
> ...



It can reduce your power consumption. It can also scale up the coil, and rot it out quicker.


Unfortunately. Your A/C isn't on a separate meter, so we could see the true reduction. Your graph points out that you have something else using a good amount of power. Since it shows a large drop in KWH on Wednesday the 25th, compared to Monday the 23rd. Both days were 96°F outside.


Sunday the 29th you used the most KWHs even though it was only 94°F outside. 2° cooler than the hottest day the chart shows.


Look at Tuesday and Wednesday the 31st and first of Aug. Same outdoor temps, but different KWHs used. With Wednesday being higher than Tuesday. 



After you have used your mister for a few years, let us know how well it is working, and how well your A/C is holding up to the mister.


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## user_12345a (Nov 23, 2014)

What kind of water filtration system do you have?

The only types I know of that can remove minerals well are reverse osmosis and distillation types.

The ion exchange softeners just replace the atoms which cause water to be hard with sodium atoms. I can only assume you would still get some buildup as the water evaporates.

Corrosion could still be an issue too.


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## supers05 (May 23, 2015)

user_12345a said:


> What kind of water filtration system do you have?
> 
> The only types I know of that can remove minerals well are reverse osmosis and distillation types.
> 
> ...


And the salt ions increase the galvanic corrosion. 

Cheers!


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## user_12345a (Nov 23, 2014)

It's not salt that goes into the water, right?

It's only the sodium part of the salt that replaces calcium, magnesium, etc. I wouldn't know what the sodium does when water evaporates, it can't exist on it's own.


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## supers05 (May 23, 2015)

user_12345a said:


> It's not salt that goes into the water, right?
> 
> It's only the sodium part of the salt that replaces calcium, magnesium, etc. I wouldn't know what the sodium does when water evaporates, it can't exist on it's own.


Sodium is salt. (or i should say a salt.) when sodium chloride crystallizes we call it table salt. 

Cheers!


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## user_12345a (Nov 23, 2014)

Where does the chloride come from though? 

It's only the sodium that gets put in the water, the salt is just used to replenish the resin with sodium.

My knowledge of this is limited, just from a water treatment course i had to take.


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## etsherman (Aug 2, 2011)

No it's not a salt based system. I really don't have a problem with sodium or calcium build up in the house. I installed a whole hose water filtration system a few years ago and it works as expected. I basically get bottled quality water through the whole house including the faucet supplying water to the misting system.


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## supers05 (May 23, 2015)

user_12345a said:


> Where does the chloride come from though?
> 
> It's only the sodium that gets put in the water, the salt is just used to replenish the resin with sodium.
> 
> My knowledge of this is limited, just from a water treatment course i had to take.


Sodium readily oxidizes. Chlorine is often found in municipal water. It's also found naturally in nature. Sodium compound don't evaporate at livable temperatures. They will settle on surfaces. It forms weak bonds and can react with other compounds. Most importantly the free irons in water significantly increase conductivity, which significantly increases galvanic corrosion. There is always additional sodium or potassium in the water. 

PS. A salt is a category of compounds in chemistry. (The compound has a neutral charge.) it is a vast group of compounds, including most of the periodic elements and spanning a large number of characteristics. In this case it's a salt with sodium, which is used in the process. 


Cheers!


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## supers05 (May 23, 2015)

etsherman said:


> No it's not a salt based system. I really don't have a problem with sodium or calcium build up in the house. I installed a whole hose water filtration system a few years ago and it works as expected. I basically get bottled quality water through the whole house including the faucet supplying water to the misting system.


Now I'm curious. It must be some RO system to keep up with your loads. The other systems are generally either to expensive or require handling stuff like lime. Electrical Water conditioning on the other hand can reduce the effects of hard water, until evaporation occurs. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Now I'm curious. It must be some RO system to keep up with your loads. The other systems are generally either to expensive or require handling stuff like lime. Electrical Water conditioning on the other hand can reduce the effects of hard water, until evaporation occurs.
> 
> Cheers!


Culligan whole house water filtration system. Installed about 3 years ago. Works well.


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## supers05 (May 23, 2015)

etsherman said:


> Culligan whole house water filtration system. Installed about 3 years ago. Works well.


That's a brand, not a system. They sell many different types. 

Cheers!


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## etsherman (Aug 2, 2011)

08/03/2018 Update:

Now with three full days running my a/c misting system the numbers shows that adding the water mist does have a significant impact on the efficiency of the unit since it sits in direct sunlight on the west side of the property for most of the day. I activated this system at 3:00 pm on Monday August 30th. Nothing changed in the house for the last 3 or 4 days. Thermostat still set to 75 degrees, we have a gas dryer and the usual power usage for tv's, cooking, lights, computers, etc. The only variable that changed was adding misters to the outside a/c unit and the power consumption dropped by 44%.

I see a lot of comments regarding minerals in the water will damage the a/c unit for which I thoroughly evaluated and considered before adding the misters. I look at it this way, the water on my property goes through a whole house filtration system plus as a backup I added a specific calcium filter to the misters. Now, if that water is good enough for human, pet and plant consumption then surely a piece of metal machinery can stand a spray mist of the same water a few times during a day. Those mister use a very fine hole to spray through ... if calcium was a real problem using my water supply then those small hole will become clogged and I will start to see calcium build up on the cabinet long before it happens on the fins and coil. If the should happen, I would then clean the unit and shut the misters off.


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## supers05 (May 23, 2015)

etsherman said:


> 08/03/2018 Update:
> 
> Now with three full days running my a/c misting system the numbers shows that adding the water mist does have a significant impact on the efficiency of the unit since it sits in direct sunlight on the west side of the property for most of the day. I activated this system at 3:00 pm on Monday August 30th. Nothing changed in the house for the last 3 or 4 days. Thermostat still set to 75 degrees, we have a gas dryer and the usual power usage for tv's, cooking, lights, computers, etc. The only variable that changed was adding misters to the outside a/c unit and the power consumption dropped by 44%.
> 
> I see a lot of comments regarding minerals in the water will damage the a/c unit for which I thoroughly evaluated and considered before adding the misters. I look at it this way, the water on my property goes through a whole house filtration system plus as a backup I added a specific calcium filter to the misters. Now, if that water is good enough for human, pet and plant consumption then surely a piece of metal machinery can stand a spray mist of the same water a few times during a day. Those mister use a very fine hole to spray through ... if calcium was a real problem using my water supply then those small hole will become clogged and I will start to see calcium build up on the cabinet long before it happens on the fins and coil. If the should happen, I would then clean the unit and shut the misters off.


Sorry but i have to completely disagree. Firstly, it's closer to 35%, +/-2%. (estimated from the graph as you don't have numbers there. Did not normalise for temperature. Average daily temp is a better metric then day time high.)

Secondly, the buildup of minerals is fairly minor. You will separate your aluminum fins from the copper tubes with constant water on them. The more ions in the water, the worse it'll be. Your essentially setting up a weak battery. 

The mineral buildup can be mitigated, and some is removable using descaling products. However, aluminum can be damaged with these products. So all aluminum coils also have problems 

Misters are not new. Sprinklers are often used on supermarket condensers as they start to fail. (same separation of the aluminum fins and copper tubes due to rain water over a significant timeframe.) It's a band-aid solution as it causes the reaction to accelerate. But hiring a crane and scheduling a shutdown of the store can be troublesome. 

Cheers!


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## beenthere (Oct 11, 2008)

The misting effect is the same whether the condenser sits in the sun light or shade. The sun light was never part of the influence on the condenser.


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## etsherman (Aug 2, 2011)

On a serious note ... A/C manufactures should design coils and fins that can withstand a mist of water that's meant for human consumption as much as those units sell for now even without installation!!!. 

I may start a campaign going to get that started ... LOL!!


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## supers05 (May 23, 2015)

etsherman said:


> On a serious note ... A/C manufactures should design coils and fins that can withstand a mist of water that's meant for human consumption as much as those units sell for now even without installation!!!.
> 
> I may start a campaign going to get that started ... LOL!!


Pure water, such as from reverse osmosis or condensate will be suitable for this application. Water is highly reactive, and the impurities only add to it. Our bodies just happen to require that reactive potential. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> On a serious note ... A/C manufactures should design coils and fins that can withstand a mist of water that's meant for human consumption as much as those units sell for now even without installation!!!.
> 
> I may start a campaign going to get that started ... LOL!!



They make them able to stand up to rain water.


We require minerals to live. Just so happens, those very minerals aren't good for the A/C. Specially when a mister is putting them on the A/C.


The harm stems from the evaporation of the water. Leaving the mineral deposit. Rain doesn't leave the deposit, most because very litte of the water evaporates. Compared to how much fell on the condenser.


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## etsherman (Aug 2, 2011)

beenthere said:


> They make them able to stand up to rain water.
> 
> 
> We require minerals to live. Just so happens, those very minerals aren't good for the A/C. Specially when a mister is putting them on the A/C.
> ...


I understand by why not make it to stand up to tap/city water???

I guess I'm just more optimistic about it since it's doing exactly what I had expected. 

A few items listed below to which a lot of people said was not a good idea but with slight modifications they all survived and are thriving today: 

ATM Machines
Cell Phones
Aluminum Wheels on Cars
Bacon Fat
Personal Computers
The World Wide Web
Satellite Television
KFC - was told by 1,000 bankers no ... people only ate chicken on Sunday's.
Cordless Tools
Microsoft Windows
Solar Power
Electric Cars
Fax Machine
Email
Direct Deposit
Credit Cards
Electronic Banking
Remote Desktop Access
UBER
Online Shopping
etc., etc.

Just to name a few!!! Therefore, I feel a manufactured water cooled a/c unit for household use is not that far of a stretch!!! IJS


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## beenthere (Oct 11, 2008)

etsherman said:


> I understand by why not make it to stand up to tap/city water???
> 
> I guess I'm just more optimistic about it since it's doing exactly what I had expected.
> 
> ...



You didn't buy an A/C that is for water use. You can buy a water sourced A/C. They make them.


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## user_12345a (Nov 23, 2014)

There's water source a/c which is really wasteful unless you have a ground loop, free water (sitting on a lake or something) or have a pool to heat. 

There could be some commercial air cooled condensers designed to be aided with evaporation.

Cooling towers are evaporative but there's no coil to damage, they use a fill material which can be replaced, the minerals stay in the water left but the concentration goes up -> they take specific steps to make sure the mineral content doesn't get too high.


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## etsherman (Aug 2, 2011)

Misting may not be for everyone but for my situation it works ... and at the end of the day that's really all that matters. Thanks for all your comments.

Going enjoy the weekend.


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## supers05 (May 23, 2015)

user_12345a said:


> ...
> There could be some commercial air cooled condensers designed to be aided with evaporation.....


Window and portable ACs, along with refrigerators use evaporative condensing loops. They have no fins on that portion which runs through a plastic tray. 

There's ways to achieve this. If the OP really wanted, he could throw in a Stainless coaxial or plate heat exchanger after the condensing coil and get the same result. 


Cheers!


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## u3b3rg33k (Jul 17, 2018)

etsherman said:


> 08/03/2018 Update:
> 
> Now with three full days running my a/c misting system the numbers shows that adding the water mist does have a significant impact on the efficiency of the unit *since it sits in direct sunlight on the west side of the property for most of the day.* I activated this system at 3:00 pm on Monday August 30th. Nothing changed in the house for the last 3 or 4 days. Thermostat still set to 75 degrees, we have a gas dryer and the usual power usage for tv's, cooking, lights, computers, etc. The only variable that changed was adding misters to the outside a/c unit and the power consumption dropped by 44%.
> 
> I see a lot of comments regarding minerals in the water will damage the a/c unit for which I thoroughly evaluated and considered before adding the misters. I look at it this way, the water on my property goes through a whole house filtration system plus as a backup I added a specific calcium filter to the misters. Now, if that water is good enough for human, pet and plant consumption then surely a piece of metal machinery can stand a spray mist of the same water a few times during a day. Those mister use a very fine hole to spray through ... if calcium was a real problem using my water supply then those small hole will become clogged and I will start to see calcium build up on the cabinet long before it happens on the fins and coil. If the should happen, I would then clean the unit and shut the misters off.


lemme stop you there. your AC doesn't use radiant heat to transfer energy, it uses air - the biggest factor is going to be condenser coil air inlet temp, not wether it's in the sun or not. 



> here’s an assumption that the sun shining directly onto the unit causes the whole thing to heat up like a brick. Now, shading the condenser might reduce the sun’s heat on the casing but the condenser’s casing doesn’t conduct that much heat to the internal fins and tubing. In fact, all those bits are already under shade inside the case.
> 
> FSEC points out that a 3 ton condenser moves 170,000 cubic feet of air per hour. That’s like the air inside a 55 foot cube. So during that hour a portion of that 55 foot cube of air is being replaced from beyond the immediate area. If only the condenser is kept shaded by a trellis or bushes, or some kind of structure, then the amount of air moving through the condenser won’t have time to cool down within the shaded area.
> source:http://swww.directenergy.com/blog/shading-air-conditioner-myths/


remember, the sun puts out about 1kW/sq yard in full sun. 
how much does 1kWh raise the temp of 170k Cuft of air? 
1kWh = 3412.14 BTU
the specific heat (Cp) of air is 0.24 BTU per pound per degree Fahrenheit
1 cubic foot of air at standard temperature and pressure assuming average composition weighs approximately 0.0807 lbs.
170000cuft * 0.0807 lbs = 13,719 lbs of air
13719lbs air * 0.24 btu/deg/lb = 3292.56 BTU per degree
3292.56 btu/degree / 3412.14 BTU = 0.9649545447 == 1 degree

so 1kwh raises the temp of 170k cu/ft of air by about 1 degree. 

shade doesn't do much here.


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## SeniorSitizen (Sep 10, 2012)

The sun heats the sheet metal to maybe 130 degrees. The air that cools the coils passes by that 130° sheet metal on its way to the coils, so why not shade the condenser to reduce the sheet metal to 95° when possible.


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## beenthere (Oct 11, 2008)

SeniorSitizen said:


> The sun heats the sheet metal to maybe 130 degrees. The air that cools the coils passes by that 130° sheet metal on its way to the coils, so why not shade the condenser to reduce the sheet metal to 95° when possible.



You can if you want, no harm either way. But the sheet metal being warm/hot, doesn't effect the condensers operation.


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## supers05 (May 23, 2015)

u3b3rg33k said:


> lemme stop you there. your AC doesn't use radiant heat to transfer energy, it uses air - the biggest factor is going to be condenser coil air inlet temp, not wether it's in the sun or not.
> 
> 
> 
> ...


Your math and physics is a bit off. The energy that we receive from the sun is via radiation. Air only absorbs a very small fraction and allows the rest to pass. Heated surfaces then heat the air. Reflective surfaces like aluminum absorb much less energy. 

Either way, the point is the same. Solar gain is extremely minimal when considering condensing units. The ambient air temp is the major factor. If that air is heated by warm surfaces, then yes the AC will have to work harder. It's more likely that there's some recirculation occurring causing even warmer temps. 

Cheers!


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## etsherman (Aug 2, 2011)

SeniorSitizen said:


> The sun heats the sheet metal to maybe 130 degrees. The air that cools the coils passes by that 130° sheet metal on its way to the coils, so why not shade the condenser to reduce the sheet metal to 95° when possible.


Yep ... That was my thinking and what I was referring to in the original post.


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## supers05 (May 23, 2015)

etsherman said:


> Yep ... That was my thinking and what I was referring to in the original post.


If it's 130*f you aren't bleeding much heat to the air. I can hit that when working with ductwork on a roof. No airflow and it'll hit that fairly easily in the summer. You feel just as hot when it reflects the sun back on you.

As for it starting with it hot, the unit needs to build pressure before it starts working correctly anyways. That can take a few moments. By then the fan has been moving air for at least a few seconds if not more. You've already pulled most of that solar heat off of the panels even before it really starts to cool. 

PS. I'm much more north then you. 

Now a few buildings have flooded their roof during the hottest days to mitigate that solar pickup. The evaporating water keeps the roof cool, which significant reduces the load on poorly insulated buildings. They just can't keep the water there long term, as it starts to grow a swamp. [emoji23] Green roofs are the next step on that. The grass/plants evaporate a lot of water, cooling the vegetation. It also absorbs significant amounts of solar energy and converts it into chemical energy. Too bad they cost so much to maintain. 

Cheers!


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## u3b3rg33k (Jul 17, 2018)

supers05 said:


> Your math and physics is a bit off. The energy that we receive from the sun is via radiation. Air only absorbs a very small fraction and allows the rest to pass. Heated surfaces then heat the air. Reflective surfaces like aluminum absorb much less energy.
> 
> Either way, the point is the same. Solar gain is extremely minimal when considering condensing units. The ambient air temp is the major factor. If that air is heated by warm surfaces, then yes the AC will have to work harder. It's more likely that there's some recirculation occurring causing even warmer temps.
> 
> Cheers!


yeah the numbers are quite off - it's not exactly 1kw/m^2, i assumed the sides of the AC are 1m^2 black body radiators perpendicular to the sun that transfer 100% of the radiated thermal energy to the surrounding air, and I didn't double check any of the figures I got for any of the specs. they seemed close enough to reality to be useful for a ballpark demonstration though. even if i'm 200% off, it's still a trivial effect. ambient air temp matters so much more.


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## SeniorSitizen (Sep 10, 2012)

QUOTE:By then the fan has been moving air for at least a few seconds if not more. You've already pulled most of that solar heat off of the panels even before it really starts to cool. 

********************************************
OH, but the sun doesn't stop heating that area a few seconds after the fan starts. It continues doing its pre-heating thing as long as the fan is running or until it sets at the horizon.:biggrin2:


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## supers05 (May 23, 2015)

SeniorSitizen said:


> QUOTE:By then the fan has been moving air for at least a few seconds if not more. You've already pulled most of that solar heat off of the panels even before it really starts to cool.
> 
> ********************************************
> OH, but the sun doesn't stop heating that area a few seconds after the fan starts. It continues doing its pre-heating thing as long as the fan is running or until it sets at the horizon.:biggrin2:


The amount of air that you're moving is quite a bit. Metal of a great conductor. (electricity and heat. Just hold up a rod during a lighting storm if you don't believe me. [emoji23]) It'll give off that heat almost immediately, and continue to do so. Depending on the paint, only a portion of the energy hitting it is actually absorbed, the rest is reflected. So that means even less energy to heat the surface. If you want to try it out, touch the side of that car/truck sitting in the sun for a while. It'll burn you. Drive it down the street and touch it. It'll be just above air temp by then. (I'm one of those people that rest their arm on door with the window down in great weather. Try it, it only takes a few moments of driving faster then an idle to put your arm on that door.) 

Cheers!


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## slwtypmark (May 17, 2018)

OMG!..Are we really still talking about creating 'Shade' for a Condenser "98" Posts later including recorded temps of the metal & 'Sun Heat Gain' formulas!???(and no, u3b..I Did Not remember that the Sun puts out "1kW/sq.yd"!)


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## supers05 (May 23, 2015)

slwtypmark said:


> OMG!..Are we really still talking about creating 'Shade' for a Condenser "98" Posts later including recorded temps of the metal & 'Sun Heat Gain' formulas!???(and no, u3b..I Did Not remember that the Sun puts out "1kW/sq.yd"!)


Actually 101 posts now. 

Clearly a few of us are bored..... It's the sun for me. It's baking my brain. 

Cheers!


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## SeniorSitizen (Sep 10, 2012)

supers05 said:


> The amount of air that you're moving is quite a bit. Metal of a great conductor. (electricity and heat. Just hold up a rod during a lighting storm if you don't believe me. ) It'll give off that heat almost immediately, and continue to do so. Depending on the paint, only a portion of the energy hitting it is actually absorbed, the rest is reflected. So that means even less energy to heat the surface. If you want to try it out, touch the side of that car/truck sitting in the sun for a while. It'll burn you. Drive it down the street and touch it. It'll be just above air temp by then. (I'm one of those people that rest their arm on door with the window down in great weather. Try it, it only takes a few moments of driving faster then an idle to put your arm on that door.)
> 
> Cheers!


I'll try this driving the wife when it's 95°. Why you shut the A/C off? It'll cool off if we drive awhile, just be patient.:vs_laugh:


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## supers05 (May 23, 2015)

SeniorSitizen said:


> I'll try this driving the wife when it's 95°. Why you shut the A/C off? It'll cool off if we drive awhile, just be patient.:vs_laugh:


Cause the fireworks of the hot and angry wife is quite entertaining. . Tell her the AC will work once you get up to 70mph.

Cheers!


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## slwtypmark (May 17, 2018)

The old '460' car A-C works really well out on the open highway but for some reason if you get stuck sitting in a construction zone, it will just Shut Off!


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## beenthere (Oct 11, 2008)

SeniorSitizen said:


> QUOTE:By then the fan has been moving air for at least a few seconds if not more. You've already pulled most of that solar heat off of the panels even before it really starts to cool.
> 
> ********************************************
> OH, but the sun doesn't stop heating that area a few seconds after the fan starts. It continues doing its pre-heating thing as long as the fan is running or until it sets at the horizon.:biggrin2:


 I didn't know we were talking about an oven. lol


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## SeniorSitizen (Sep 10, 2012)

I've walked up on rattle snakes stretched out in the shade of a utility pole when it was 105° and it seems a warm blood snake knows enough to get it the shade at those temperatures.:vs_laugh:


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## supers05 (May 23, 2015)

SeniorSitizen said:


> I've walked up on rattle snakes stretched out in the shade of a utility pole when it was 105° and it seems a warm blood snake knows enough to get it the shade at those temperatures.:vs_laugh:


We might be on top of the food chain, but we aren't very smart. 

Cheers!


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## beenthere (Oct 11, 2008)

SeniorSitizen said:


> I've walked up on rattle snakes stretched out in the shade of a utility pole when it was 105° and it seems a warm blood snake knows enough to get it the shade at those temperatures.:vs_laugh:



It started out laying in the sun light. But as the day wore on, the shade moved to where the snake was. The snake just didn't bother moving.


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## etsherman (Aug 2, 2011)

The jury is in and the verdict is ... TRUE!!! Cooling your outdoor a/c unit with water misters and or shade does drastically impact the efficiency of the equipment in terms of less power usage. Looking at the attached graph for the last two weeks of kWh's used clearly demonstrates this. The only variable that changed was adding the a/c misting kit on Monday, July 30th at 3:00 pm. You can clearly see how the outside temperature forced the unit to fluctuate power usage on various days to hit the 75° inside temperature setting. After the misters were added the power usage of the compressor leveled out using the same amount of kWh's to maintain the same 75° inside temp while still having 98° high temp days. Nothing changed inside the house as far a our daily routines. 

Adding a shade structure may not be necessary because the misters actually cool down the cabinet. That's why I am testing with 3 nozzles on each side. I will cut those down to 1 on each side. 

Again, thanks all for comments and expertise!!! Now time for some Texas BBQ and a beer!!!


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## beenthere (Oct 11, 2008)

Well, since you didn't do any charting of just shading. You still haven't found out that shading doesn't help. No one has said that misting won't reduce work load on the A/C. Just that it has ill long term effects on the A/C. 



Misting has been used in commercial applications for a long long time.



I would like to point out though. That the temps in the post you just made, are now 4 to 5 degrees higher for the same days as in the post you made on 8/3/18. 



I'm sure its just some accidental mix up. But inconsistencies like that, make anything you want to post as proof questionable.


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## supers05 (May 23, 2015)

etsherman said:


> The jury is in and the verdict is ... TRUE!!! Cooling your outdoor a/c unit with water misters and or shade does drastically impact the efficiency of the equipment in terms of less power usage. ....


No, you've only tested the misting. While we have advised you of the consequences of using misters, they do have the benefit of lowering electricity usage. (with other visible and hidden associated costs.) You have not tested shading in any significant way. 

Cheers!


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## digitalplumber (Jul 8, 2011)

Humidity has also been different here lately also!


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## supers05 (May 23, 2015)

digitalplumber said:


> Humidity has also been different here lately also!


Which will effect the internal loads and the effectiveness of the misters. (misters are very effective in dry locations, and almost ineffective in humid areas.) 

Cheers!


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## etsherman (Aug 2, 2011)

beenthere said:


> Well, since you didn't do any charting of just shading. You still haven't found out that shading doesn't help. No one has said that misting won't reduce work load on the A/C. Just that it has ill long term effects on the A/C.
> 
> 
> 
> ...



My electric provider used the recorded high temps for an area they probably consider central Houston. I live in a suburb of Houston and pulled the recorded high temps for my specific zip code. The monitoring station is 3 miles from my home. That's why I posted the exact high temps more relative to my property. It's all stored online!!!


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## supers05 (May 23, 2015)

etsherman said:


> My electric provider used the record high temps for an area they probably consider central Houston. I live in a suburb of Houston and pulled the recorded high temps for my specific zip code. The monitoring station is 3 miles from my home. That's why I posted the exact high temps more relative to my property. It's all stored online!!!


Use the daily average temps. They should also be available. A day with a lower daily high, but a higher average temp will cause a higher load on the house then day with the extreme high but lower average temp. 

Cheers!


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## user_12345a (Nov 23, 2014)

Watch grey furnace man's recent videos on misters and shading: https://www.youtube.com/user/grayfurnaceman/videos

The savings are basically non-existent with an exception of reducing compressor amp draw by under 10%, using misters.


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## etsherman (Aug 2, 2011)

supers05 said:


> No, you've only tested the misting. While we have advised you of the consequences of using misters, they do have the benefit of lowering electricity usage. (with other visible and hidden associated costs.) You have not tested shading in any significant way.
> 
> Cheers!


Incorrect ... Shading that unit will be a challenge because of HOA regulations and I have about 12 inches on the west side of the unit before I hit the property line. HVAC tech recommends at least 18 to 24 inches between any louvered type of shading to allow proper ventilation. Looking at various options, even the retractable awning extended out 5 ft. from the wall over the unit at an angle will not properly shade the unit from that west sun beaming down on it. It has to be some type of structure standing a minimum of 5 ft. tall facing the house on the west side of the a/c not hanging off the house looking west as in my original post. HOA will make me remove that. 

Most of those misting kits comes with 3 nozzles basically one for each side. Once I realized that shading was not going to be easy ... I built this misting kit with 3 nozzles per side. The extra mist compensates for not having the unit shaded as it really cools that cabinet down real quickly and does the same as a shade structure would do which is keep the overall unit cool. Doesn't matter if it is cooled by water or shade to be honest at this point. 

That's why I focused more on the misters rather than try to shade the unit!!!


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## etsherman (Aug 2, 2011)

supers05 said:


> Use the daily average temps. They should also be available. A day with a lower daily high, but a higher average temp will cause a higher load on the house then day with the extreme high but lower average temp.
> 
> Cheers!


I wanted to say recorded high temps not the record high temps for the day.

Sorry for the confusion.


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## etsherman (Aug 2, 2011)

user_12345a said:


> Watch grey furnace man's recent videos on misters and shading: https://www.youtube.com/user/grayfurnaceman/videos
> 
> The savings are basically non-existent with an exception of reducing compressor amp draw by under 10%, using misters.


Two different set of metrics ... he is measuring head pressure on the unit and I am gauging kWh's used from the power company. 

Again, shading is probably not that big of a gain as using a water misting system.


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## user_12345a (Nov 23, 2014)

The primary reason why misters or shading would be considered is to reduce the head pressure.

No head pressure drop? No drop in current!

Shading does nothing.

He had two videos on misters too, in the first I believe he did measure amperages and it made a difference but not significant.

Taking direct measurements at the unit under the same conditions is far more accurate than trying to determine savings based on total house electricity consumption.

There are too many variables.


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## supers05 (May 23, 2015)

etsherman said:


> Incorrect ... Shading that unit will be a challenge because of HOA regulations


That simply doesn't concern the fact that you haven't providing testing of shading in any measurable way. 

Sorry, you simply don't understand the physics behind this. Shading the unit, without shading the house simply has negligible effect on the unit. 

Cheers!


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## supers05 (May 23, 2015)

etsherman said:


> I wanted to say recorded high temps not the record high temps for the day.
> 
> Sorry for the confusion.


Not record highs, or even daily highs. Neither is sufficient. Average daily temperature, including the night, is the number you need to use. 

Cheers!


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## user_12345a (Nov 23, 2014)

From average temperature, you can calculate cooling degree days, subtract minimum average temp at which cooling is required at from average temp and you get a good measure of how much cooling is needed each day.

But it doesn't take solar heat gain into account. You can have a very warm cloudy day with very much reduced cooling needs.


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## etsherman (Aug 2, 2011)

supers05 said:


> Not record highs, or even daily highs. Neither is sufficient. Average daily temperature, including the night, is the number you need to use.
> 
> Cheers!


Yep, Average daily temps would present another view but the unit works the hardest during the daily high temp hours ... that's all I am concerned with.

I will let the misters run the rest of the summer and check the unit periodically. If I come up with a decent shade structure I may do some testing while turning the misters off. For now they solved my problem of avoiding an extremely large electric bill for the next couple of months. 

Thanks


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## supers05 (May 23, 2015)

user_12345a said:


> From average temperature, you can calculate cooling degree days, subtract minimum average temp at which cooling is required at from average temp and you get a good measure of how much cooling is needed each day.
> 
> But it doesn't take solar heat gain into account. You can have a very warm cloudy day with very much reduced cooling needs.


Unfortunately, without solar panels and accurate records, or some other measure, that is simply not available. Each house will have a different solar load depending on vegetation, and cloud cover. Even as simple as having window coverings open or closed will have significant changes in solar load. That goes in hand with occupancy load. 

Cheers!


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## user_12345a (Nov 23, 2014)

They use cooling and heating degree days for commercial applications all the time to compensate for weather when calculating energy savings from a retrofit.

It's not perfectly accurate due to the reasons you stated, but better than not adjusting for weather.


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## etsherman (Aug 2, 2011)

supers05 said:


> That simply doesn't concern the fact that you haven't providing testing of shading in any measurable way.
> 
> Sorry, you simply don't understand the physics behind this. Shading the unit, without shading the house simply has negligible effect on the unit.
> 
> Cheers!


supers05, I stated in several posts a ways back that the concept of shading the a/c unit was scrapped once I realized that the brick wall on the house next to the unit was supplying a ton of heat to the surrounding air the unit is sucking in. That wall and a/c unit is facing straight west with no shading from trees, etc. On a 90° day you can stand next to that wall after the sun goes down and still feel heat being radiated from those bricks. That's why I changed the focus to water misters instead of trying to shade the a/c unit. Forget about shade testing ... we already know the heat coming off the brick wall will defeat any type of shading done to just the a/c unit, ok.

The water misters cools the air the unit is sucking in regardless of where the heat source is coming from and it also cools the equipment down. That's why it works more efficiently when the misters are running.

Thanks


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## beenthere (Oct 11, 2008)

So have you checked to see how much water a minute your misting system uses.


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## digitalplumber (Jul 8, 2011)

Maybe he should mist the brick, if it helps that much on the AC!


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## etsherman (Aug 2, 2011)

Here is something else I happen to notice. At the height of a 90° day (starting around 2:30 pm) with the misters going, only 3 (one on each side of the unit not the nine shown in the video), thermostat set at 75° inside ... the temp of the air coming out of the vents that are farthest from the inside air handler reads 66.7°. With the misters turned off the air temp at the same vents is 71°.

That proves that misting an a/c unit makes is work SIGNIFICANTLY more efficiently especially during the hottest portion of the day.

I feel that a/c manufactures should be required to design coils/fins to withstand a mist of water that's fit for human consumption. After all, the unit sits outside in the weather its entire lifespan, been through several storms and other extreme weather events but a little mist of water can destroy it. Really!!! Just like down south with extreme hot summers ... builders should be required to install double pane windows like they do up north for extreme cold climates. Now companies want to charge upwards of 10k to install some vinyl double pane windows for which some have actually melted in this Texas heat!! I got a quote to replace the windows in my home with quality aluminum frame double pane windows and I'm still in awe of the price!!! You would need a second mortgage!!! 

That's why solar screens are a big business down here and I invested in them a few years ago ... They really do make a big difference especially on the east side windows and they don't allow much heat to enter those front single pane windows. They look darker than what they really are and when looking out from inside the house it's like looking through sunglasses. Solar Screens are a lot less expensive than a set of 25k double pane windows. Since we don't have extreme cold days here for long periods of time ... you can manage with single pane windows during the winter months ... summer is the main issue!!!.


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## supers05 (May 23, 2015)

To bad that trees don't provide better shade for your whole house. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> To bad that trees don't provide better shade for your whole house.
> 
> Cheers!


Yes, if I had some on that on the west side I'd be much better off!!!


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## supers05 (May 23, 2015)

etsherman said:


> Yes, if I had some on that on the west side I'd be much better off!!!


Maybe one day, we'll engineer trees to grow and cover exactly what we need and no more. No leaves to pickup, and lives forever.

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Maybe one day, we'll engineer trees to grow and cover exactly what we need and no more. No leaves to pickup, and lives forever.
> 
> Cheers!


LOL ... That's probably not a far stretch!!!


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## etsherman (Aug 2, 2011)

beenthere said:


> So have you checked to see how much water a minute your misting system uses.


beenthere, the small amount of water it takes to supply those current 3 nozzles is not really an issue for me since the amount of water needed is minimal to be honest. The water usage will not offset the savings from the decreased kWh's saved on the compressor running more efficiently on extremely hot days.

Speaking of water ... watch the video of my two dogs below. I made them a custom dog water fountain because birds and other animals were getting into their water bowls pooping in them thus making the pets sick. I trained them how to use it one time and it works like a charm. No more stale, dirty and contaminated water for the dogs. It uses their body weight to open a drinking fountain faucet ... pretty simple but it works. It is kept in the shade all day long with a insulated short supply hose. They get cool, fresh drinking water on demand 24 hours a day. Some would also ask the question how much water per minute the fountain uses but that's not the point or focus. The amazing thing is ... they only use the fountain when they need to and are more conservative with it than most humans!!!


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## beenthere (Oct 11, 2008)

etsherman said:


> beenthere, the small amount of water it takes to supply those current 3 nozzles is not really an issue for me since the amount of water needed is minimal to be honest. The water usage will not offset the savings from the decreased kWh's saved on the compressor running more efficiently on extremely hot days.



Small amount of water, varies by a persons opinion.


So is a small amount a quart a minute, or 2 gallons a minute.


Can just watch your water meter for a minute while nothing else is using water to find out. 



You may be using 24 gallons a day, or 240 plus gallons a day. Not a small amount if more than 25 gallons a day.


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## digitalplumber (Jul 8, 2011)

66 and 71 vent discharge temps, I still say something is wrong with the system. My downstairs discharge temp at vents is 58, everyday.


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## SeniorSitizen (Sep 10, 2012)

digitalplumber said:


> 66 and 71 vent discharge temps, I still say something is wrong with the system. My downstairs discharge temp at vents is 58, everyday.


Yep, needs to be checking supply temperature differential between the unit plenum and distant registers. I'm smelling :smile: possible duct work upgrade in the attic. A good DIY endeavor in December.


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## etsherman (Aug 2, 2011)

SeniorSitizen said:


> Yep, needs to be checking supply temperature differential between the unit plenum and distant registers. I'm smelling :smile: possible duct work upgrade in the attic. A good DIY endeavor in December.


SeniorSitizen and digitalplumber ... Sorry for the confusion. My original a/c temps readings were directed at the air temp around the vents standing about 6 ft. back ... Not the air temp directly coming out of the vents. I was trying to see what the air temp was in the room after the air had been mixed with what was coming out of the vents.

Here are the actual readings of the air temp straight in the vents.

Farthest A/C Vent Air Temp = 57.5 °F
Closest A/C Vent Air Temp = 41.1 °F

Thanks!


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## SeniorSitizen (Sep 10, 2012)

etsherman said:


> SeniorSitizen and digitalplumber ... Sorry for the confusion. My original a/c temps readings were directed at the air temp around the vents standing about 6 ft. back ... Not the air temp directly coming out of the vents. I was trying to see what the air temp was in the room after the air had been mixed with what was coming out of the vents.
> 
> Here are the actual readings of the air temp straight in the vents.
> 
> ...


Our unit doesn't have supply ducts in the attic so possibly someone else will suggest a normal/average temperature loss with xx size duct, xx type of duct, xx length and xx insulation value for supply ducts, BUT, 16.4° seems real suspicious to me.
Our unit does have about 30 ft. of 14" flex duct return in the 130° attic that was picking up about 4° air temperature in its travels. My techie suggested additional insulation beyond what it was manufactured with and knocked that 4° loss down to 0.2°.


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## etsherman (Aug 2, 2011)

My a/c duct work was installed in 1985 with one section changed out a few years ago. That farthest duct is a loooooong way from the air handler in terms of length and I believe two junction boxes to feed several other rooms off the main line.

I can live with 57.5° at the farthest vent on a hot 90° Houston day to be honest.

This is how my dutch work and vents are laid out.


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## user_12345a (Nov 23, 2014)

> Here are the actual readings of the air temp straight in the vents.
> 
> Farthest A/C Vent Air Temp = 57.5 °F
> Closest A/C Vent Air Temp = 41.1 °F


You likely have low airflow and fixing the ductwork would save way more than misters.

Supply 41 is very low unless you have like 60-64f return air, which you shouldn't. 

The low airflow raises duct loss.


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## SeniorSitizen (Sep 10, 2012)

user_12345a said:


> Supply 41 is very low unless you have like 60-64f return air, which you shouldn't.


Agree and with his stat set at 75 the return air could easily be 78 at a ceiling return air grille and the closest supply register being 41 that's, well I'm seeing conflicting information with 37° DT. 



On a good day a 20° DT makes me happy and I'll even live with 18 degrees DT on a bad day.:biggrin2:


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## etsherman (Aug 2, 2011)

user_12345a said:


> You likely have low airflow and fixing the ductwork would save way more than misters.
> 
> Supply 41 is very low unless you have like 60-64f return air, which you shouldn't.
> 
> The low airflow raises duct loss.


Not going to change out the ducts in the house at this time. They have been inspected and appear to be in good shape considering their age. Plus, with the stat set at 75° I get even air flow all throughout the house especially with a new variable speed blower/furnace that was installed a few months ago. Even on a hot 90° day with the stat on 75° the inside of the home is very comfortable in every room!!!

Thanks


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## user_12345a (Nov 23, 2014)

Your system is probably oversized, otherwise the low airflow be reducing capacity enough for it to not keep up.

Low airflow makes oversized unit dehumidify better, compensating for being oversized.

You have problems covering up for other problems and are probably using a lot more energy than required.

When it comes to needing replacement (likely to be sooner than later if you keep on misting your coil), it would be wise to fix the problems, at least those which can be fixed without tearing into drywall/plaster.

BTW - your variable speed blower's controller may suffer a premature death due to high duct pressure. 

This motor type is designed to compensate for duct pressure and with such a low supply temp, there's a good possibility it wasn't configured properly to deliver the correct airflow for your tonnage.

This should be checked. Technicians aren't necessarily the most thorough and may not go looking for problems on a system that is working okay on the surface. (but not within manufacturer's specs, rated airflow, capacity, efficiency, charge)


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## etsherman (Aug 2, 2011)

user_12345a said:


> Your system is probably oversized, otherwise the low airflow be reducing capacity enough for it to not keep up.
> 
> Low airflow makes oversized unit dehumidify better, compensating for being oversized.
> 
> ...


user_12345a, I totally disagree with your comments above. I realize that you may be a Savant in the HVAC industry but your theories and assessments is not the Bible for every situation. You speak in terms of theory and what should be and I am speaking in terms of reality. It's impossible for you to make the decision that one should replace their entire dutch system based on a simple chat room post!!! I've never had a problem with air flow in the 33 years owing the home nor did I imply this in any of my previous posts. You are not an advocate of misting the a/c units ... I get that and respect that. Perhaps you don't fully understand what I am going to use the misters for. I'm not installing a misting system to run on the a/c unit 24 hrs a day, 365 days a year ... I am targeting the extreme hot days we have down here in Houston starting in May going through September. When the weatherman says we are going to have 90° plus days ... simply activate the misting system otherwise turn it off. Keep in mind my unit sits and bakes in the extreme west sunlight for the better part of the day. 

I have friends and co-workers with 500k homes built within the last 12 months. They have new HVAC systems, double pane windows and insulation according to building codes ... and they are complaining about $450 electric bills for the month of July. The heat we get down here will challenge the best and latest HVAC systems available, that's just a fact. 

The pictures below clearly demonstrate that there is no duct problem or restricted air flow!!! The ductwork is in proper working order and was recently inspected when the new air handler was installed a few months ago.

The return air is right at 74.5° which is exactly where is should be. The closest air vent is reading 41.1° because the misters were running making the compressor that much more efficient. If the misters were not running that temp would probably be in the high 40's or low 50's!!!


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## beenthere (Oct 11, 2008)

Based on the pics you just posted. You actually do have at least a minor air flow problem. The return flex is attached directly to the furnace. This should not be done since the blower housing is just inside that area. And the housing blocks off/interferes with the return air flow of the round flex duct. educing the return air volume, which of course reduces the supply air volume. 



It is unfortunately a common install practice, and probably all of your neighbors with A/Cs in the attic, are ducted this same way. But it is incorrect to do it that way.


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## user_12345a (Nov 23, 2014)

> I realize that you may be a Savant in the HVAC industry but your theories and assessments is not the Bible for every situation.


No, not at all, I know some theory and have limited diy experience - there are plenty of people on here who know far more than I do and will/have told you the same thing.

A few pictures mean nothing, would need pressure and cfm tests done as well as knowing duct sizes, lengths to really tell if the duct system is okay or not for the size you have.

This is theory 101; anyone will tell you, a 41 degree supply air temp is way too low and something is up. 

If you were to have the charge checked, this would show up as low suction pressure and normal to below normal suction line temperature.

It may be too low just where you measured it (part of the coil not getting enough flow or another issue) or it could be the entire air stream.

There's a chart here - http://efficientcomfort.net/charts/, the bottom half you can use to tell what the supply temp should be at various return air dry and wetbulb temps.

The supply should never be more than 30F below return if it's really dry, and at more normal humidity it should be in the 17 to 22f lower than return.

Your numbers are way off.

*As for misters dropping the temp split down from the low 50s/high 40s, it's pretty much impossible and and there are probably other factors at play you didn't take into consideration like indoor humidity.

If it was possible, capacity will increase dramatically as it gets colder outside, and it doesn't. The capacity increase as it cools off is pretty minimal, you can confirm this by looking at performance charts published by the manufacturers.

What you're doing, by misting the coil is simulating a colder day. *

-----------------


> 's impossible for you to make the decision that one should replace their entire dutch system based on a simple chat room post!!! I've never had a problem with air flow in the 33 years owing the home nor did I imply this in any of my previous posts.


You don't know if you have an airflow problem because you haven't had it measured.

It's like someone saying, they don't have any problems with blood pressure because they feel okay. Problems are often hidden.

It could be running like 300 cfm +/- per ton (400 normal), and you wouldn't know it. 

If your unit is very large for the house, you'll still get a decent amount of airflow relative to the square footage.

*But the cfm per ton can still be too low, leading to high electric bills.*

Am I suggesting you spend thousands of dollars on a working system, redoing air ducts?

No.

I am suggesting that the blower speeds should be checked now and when it actually comes time to do replacement or a major repair, it would be worth looking at modifying the duct system if the equipment can't be made to get proper cfm for the size of your outdoor unit.



> I have friends and co-workers with 500k homes built within the last 12 months. They have new HVAC systems, double pane windows and insulation according to building codes ... and they are complaining about $450 electric bills for the month of July. The heat we get down here will challenge the best and latest HVAC available.


Are you in the southern us?

The problem is that they put ducts in the attic down there. The R-8 or whatever insulation on them isn't sufficient and there's massive capacity loss to the attic.

Your measurements prove that.

It's compounded by undersized ducts, improper commissioning, etc.

Build the houses with the attic as a conditioned space, overhangs, good wall insulation (2x6, high r-value insulation), seal it well and the electric bills won't be anywhere near $450.

In canada, houses are built for the cold - they must be by code, in the southern us, seems they're put up at cheap as possible with no regard for limiting heat gain.

Misters can not fix this. There's no real way to fix an existing house unless you have very deep pockets, and who does these days?


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## supers05 (May 23, 2015)

41*f supply is too low. Design target is 50-55*f. We use 55*. With that said, your IR gun is not appropriate to measure air temp. This was already explained. 

As an aside, your Gas Line doesn't look supported. You probably should support it. In particular near the end where the flex connector starts.

User, as you increase subcooling, you gain capacity through the metering device. He is probably over charged to compensate for the low suction, caused by lower volumes. 

Cheers!


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## user_12345a (Nov 23, 2014)

> User, as you increase subcooling, you gain capacity through the metering device. He is probably over charged to compensate for the low suction, caused by lower volumes.


Except liquid stacking in the condenser reduces the area used to actually condense refrigerant and give off latent heat, which is the goal.

I'm sure there's a small capacity increase with misters - granted, I can imagine them reducing the pressure too much on fixed orifice system under certain conditions, reducing capacity.


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## supers05 (May 23, 2015)

user_12345a said:


> Except liquid stacking in the condenser reduces the area used to actually condense refrigerant and give off latent heat, which is the goal.
> 
> I'm sure there's a small capacity increase with misters - granted, I can imagine them reducing the pressure too much on fixed orifice system under certain conditions, reducing capacity.


Stacking is directly related to charge and ambient conditions. With an over charge your condensing region is much smaller, leading to higher electricity usage in the same conditions as a normal charge. The side effect is high capacity at lower ambients. (or with misters in dry places) 

(An ideal, premium unit would have a small receiver made of copper, or something other then steel. You'd control head pressure to match the rated capacity. (which would be based on the suction pressure.) It would extend the optimal efficiency envelope to all ambients that we care about. Alas, it would cost more, and add another potential failure point.) 

If the supply air really is that low, I'd expect a sst potentially dipping to or below freezing. 

Cheers!


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## etsherman (Aug 2, 2011)

beenthere said:


> Based on the pics you just posted. You actually do have at least a minor air flow problem. The return flex is attached directly to the furnace. This should not be done since the blower housing is just inside that area. And the housing blocks off/interferes with the return air flow of the round flex duct. educing the return air volume, which of course reduces the supply air volume.
> 
> 
> 
> It is unfortunately a common install practice, and probably all of your neighbors with A/Cs in the attic, are ducted this same way. But it is incorrect to do it that way.


beenthere ... I don't understand your comment here. I was in the attic when the new air handler and furnace was being installed. The return flex is attached to a flange sized to fit the inside diameter of the flex duct. That flange is on a panel that is adhered to the intake portion of the air handler. There is no obstruction of air flowing through the flex return and the intake housing on the air handler. The picture below illustrates that.

Also, the air temp at the closest vent directly under the air handler with the misters OFF is 52°. As stated earlier ... the lower 41.1° air temp was directly attributable to the misters making the compressor work more efficiently.

80% of my home has 14 ft raised ceilings ... I've never had a problem with air distribution or the problem of hot spots in some areas of the home. Air circulation is good and the temp feels pretty much balanced regardless of which room you are in. Therefore, spending time speculating about the ductwork is pointless ... Just my opinion!!!

Thanks ...


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## user_12345a (Nov 23, 2014)

You have a portion of the bottom of the air handler blanked off.



The air gets into the blower from the sides, not the middle -> with a square rather than round duct going to the air handler, and the flex connected to the square duct 2+ feet away from the furnace, it's easier for air to get drawn into the blower.

The installer took a shortcut. 



> Therefore, spending time speculating about the ductwork is pointless


The issue is not whether the distribution is even or not but rather whether the ducts permit proper airflow for the tonnage of system you have.

The ducts can be sized to deliver airflow to each room proportionally to heat gain, but if everything is undersized for the tonnage or there are significant bottlenecks, the capacity of the machine gets reduced and you get stuck with higher than normal electric bills.

Mismatched or incorrectly set up blower can cause low airflow too. Mismatched example would be 3 ton drive/blower with 4 ton a/c. Setup example - dip switches set wrong for outdoor unit size.

The reduced capacity isn't necessarily noticed if the machine is sized much larger than it needs to be. The lower than normal airflow can make the oversized unit dehumidify well.

As stated before in this thread, just because it's cooling fine on the surface, doesn't mean it's running as designed. As supers mentioned, it may have even been overcharged just to get the suction pressure up.

This was the point.


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## BayouRunner (Feb 5, 2016)

I was wondering how you were getting the low temperature readings on your supply. The return isn’t helping. We never would tie in a return like that. If I had to run a flex return it would have at least 2 ducts that size into a metal return tied into furnace. But prefer square duct. Don’t really know what your options are there. But regardless your return is too small for your system. If I understand correctly you have 2000 cfm going through a 16” duct. I didn’t read all the way back but I thought it was 5 ton system. Maybe it’s 18” but still


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## beenthere (Oct 11, 2008)

etsherman said:


> beenthere ... I don't understand your comment here. I was in the attic when the new air handler and furnace was being installed. The return flex is attached to a flange sized to fit the inside diameter of the flex duct. That flange is on a panel that is adhered to the intake portion of the air handler. There is no obstruction of air flowing through the flex return and the intake housing on the air handler. The picture below illustrates that.
> 
> Also, the air temp at the closest vent directly under the air handler with the misters OFF is 52°. As stated earlier ... the lower 41.1° air temp was directly attributable to the misters making the compressor work more efficiently.
> 
> ...



Yes, by this second pic of the return duct attachment, its attached pretty much exactly as I thought. And it is not proper. There is a restriction in air flow. You just don't know it, and haven't taken notice because you never knew what it was like if it had been done properly.

Remove the blower panel and look inside, and you might be able to understand what I am talking about.


As far as speculation about your duct work. I'm not speculating, you posted the pic of the crappy install method that was used. 


As far as convince you, I don't really care if I convince you or not. And doubt anyone can convince you of anything you don't like to hear about.


You may not have taken notice, but I said nothing about your ducts, until you posted the pic of your return set up.



Laws of Physics say you can't get more out if you put less energy in. And I see you still haven't checked, or at least haven't posted how much water per minute or hour of run time your misters are using. So you haven't shown anyone how much your real savings is. Since you didn't post what the cost of the water usage is including the sewage charge that you probably pay on that water.


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## etsherman (Aug 2, 2011)

Time to let this thread ride off into the sunset as the comments have been steered way off topic. 

1.) The original post was simply focused on adding a shade structure to the a/c unit to lower its operating temperature since it sits on the west sided of the house in direct sunlight most of the day especially the hottest portion.

2.) Adding a shade structure was not going to have much of an impact so I focused on option 2 which was adding water misters to the unit. Which solved the problem on 100° hot Houston days we have been recently experiencing.

3.) The problem was never on the inside of the house and I never indicated that in any post. Air flow, circulation and distribution inside the home is perfect and working above what is to be expected. The unit was installed by professional installers, air flow inside tested, duct work tested, outside a/c unit tested and all was OK. The QC check was done by a senior rep from the company and I signed off on the invoice. The unit has worked and is working flawlessly now. Different installers will use different methods to accomplish the same objective just like anything else. Just because something does not confirm to your methodology doesn't necessarily make it incorrect. How the return flex duct is connected to the air handler is pointless because at the end of the day ... you still have to make a round flex duct connect to a square adapter. What you are pointing out has minimal effects on the overall air distribution throughout the entire house ... so that's really not an issue for me. In the following examples ... which is correct and which is incorrect??? 

American Whiskey or Canadian Whiskey
Texas BBQ or Kansas City BBQ or Carolina BBQ or Tennessee BBQ
BMW or Mercedes
Cadillac or Lincoln
Rheem or Goodman or Carrier or Trane

4.) I never once posted here waving a flag that I have some new discovery or invention using misters to cool your a/c unit. Yet, almost every other post I am reminded that misters are not new they have been around for ages for which I am fully aware of that fact. The recent heat wave here in Houston just forced me to look further into the concept to see if it is really effective. The answer to that is yes. So please don't comment or treat it like I'm somehow trying to take credit for misters on a a/c unit!! 

5.) I'm not concerned with the mist of water or the mineral impact on the unit right now because I am still fine tuning the placement of the misters and how many will be used on a ongoing basis. Right now, three fine mist in the center of the intake grilles on each side of the unit seems to do the job just fine. Therefore, I don't need nine misters like in the original video. The water usage will be minimal to be honest. 

6.) Without the misters the unit works and keeps the house at the selected thermostat setting ... On 100° days ... it just works a lot longer to do that. This misters simply shorten those cycles and I more than proved that. To continue to debate that is, oh well!!

Again, this post has been steered too farther off topic ... so it is best just to stop responding to it.

Thanks


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## supers05 (May 23, 2015)

3) This isn't simply a methodology difference. I'd that was the case, I'd tell you how much I hate attic installs. While the unit will work with sub optimal airflow, and seem to work just fine, it'll use significantly more electricity. The vast majority of installers just don't care about how much electricity you use, so they commission it just to operate. You could save even more electricity if you wanted to sort that out. Since you appear to be a DIY sort of person, and we're a DIY site, to get those suggestions. Take it as you will.

4) We get people advocating misters all the time. Usually 2 or 3 a year. They usually end up getting to advertise their product. We have given you the benefit of the doubt.

5) We keep repeating that they aren't new, because the side effects are well known over long term use. They are generally only used during the hottest days anyways due to the water consumption. (They aren't even allowed in some places. Watering bans sometimes covers them, depending on wording.) We aren't guessing or hypothesizing. The 2 big side effects is the mineral buildup, and galvanic corrosion. As you soften the water, you increase galvanic corrosion. If want to minimize the effect, make sure that water isn't collecting directly on the coil. (Control the mist to completely evaporate before it enters the coil.) 

Good luck! 

Cheers!


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## SeniorSitizen (Sep 10, 2012)

For optimal efficiency collect the condensed water to cool the coils. It's colder than municipal water, and being the unit is in the attic design a gravity system to saturate non restrictive evaporative cooler pads. Of course we want pictures when he gets this engineering project completed and approved by the HOA.


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## user_12345a (Nov 23, 2014)

SeniorSitizen said:


> For optimal efficiency collect the condensed water to cool the coils. It's colder than municipal water, and being the unit is in the attic design a gravity system to saturate non restrictive evaporative cooler pads. Of course we want pictures when he gets this engineering project completed and approved by the HOA.


Window units are designed like that, the fan blade slings condensate on the condenser.

The water evaporating doesn't damage the coil, because it doesn't have absorbed minerals in it.

Would be difficult to do it for a central system.

Plus a project like that would be a waste of time and money in this case, it would be better to deal with the low airflow problem op refuses to acknowledge exists.

The kwh consumption of this house is what I would start to expect from a house heated with heat strips in a climate with moderate winters.

There are definitely major flaws and instead, he went to the misters.

The condenser will spring a leak and/or fill up with mineral deposits even using it a few hours each day.


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## supers05 (May 23, 2015)

user_12345a said:


> Window units are designed like that, the fan blade slings condensate on the condenser.
> 
> The water evaporating doesn't damage the coil, because it doesn't have absorbed minerals in it.
> 
> ....


Actually it is damaging, they just don't care if it lasts 10 years. 

There's a de-superheating loop in the pan, which evaporates most of the water. It's only in very humid environments where the water level reaches the slinger, which it is then sprayed into the air stream. 

Cheers!


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## digitalplumber (Jul 8, 2011)

"I have friends and co-workers with 500k homes built within the last 12 months. They have new HVAC systems, double pane windows and insulation according to building codes ... and they are complaining about $450 electric bills for the month of July. The heat we get down here will challenge the best and latest HVAC systems available, that's just a fact. "


How big is their house? What temp are they keeping it at? What other electric appliances? *Most importantly: What is their kilowatt usage and rate?*


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## supers05 (May 23, 2015)

digitalplumber said:


> "I have friends and co-workers with 500k homes built within the last 12 months. They have new HVAC systems, double pane windows and insulation according to building codes ... and they are complaining about $450 electric bills for the month of July. The heat we get down here will challenge the best and latest HVAC systems available, that's just a fact. "
> 
> 
> How big is their house? What temp are they keeping it at? What other electric appliances? *Most importantly: What is their kilowatt usage and rate?*


It doesn't really matter. If 500k is the price, you'd have a tiny townhouse in a ghetto neighborhood around here. It literally means nothing to non-locals. I think the point was that other houses in neighborhood have similar bills. (which is very uncontrolled and not scientific in any way) 

Cheers!


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## digitalplumber (Jul 8, 2011)

supers05 said:


> It doesn't really matter. If 500k is the price, you'd have a tiny townhouse in a ghetto neighborhood around here. It literally means nothing to non-locals. I think the point was that other houses in neighborhood have similar bills. (which is very uncontrolled and not scientific in any way)
> 
> Cheers!


 

Actually, I kinda know where he is and the area and the size of the homes being built there. Unlike the inner city of Houston, the suburb where he and I are, the homes are large.


Yes, inner city of Houston will get you a zero lot 2-4000 square foot townhome, 1-3 stories.


The homes he is talking about are being built in areas with no tree coverage, but lots of homes. I would be willing to bet, the friends he speaks about have large 2 stories with either 1 unit, improperly sized or 2 units under sized and running at 72 all day! Also, they are most likely paying an "affluent home" tax in high electrical rates. Mine is currently .09 per KW for 3 years.


Just a guess. My light bill last month was `123.00, upstairs on 80 and down on 75. West side of my house get the west sun. Built in 1998.


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## user_12345a (Nov 23, 2014)

Somehow I don't think texas homes are actually built with energy efficiency in mind. I doubt the central systems are properly engineered either.



> It doesn't really matter. If 500k is the price, you'd have a tiny townhouse in a ghetto neighborhood around here


You can only buy a 1 bedroom condo for that these days, with outrageous maintenance fees.

I wish you could buy a tiny townhouse in the gta for 500k.



> Actually it is damaging, they just don't care if it lasts 10 years.
> 
> There's a de-superheating loop in the pan, which evaporates most of the water. It's only in very humid environments where the water level reaches the slinger, which it is then sprayed into the air stream.


How is it different from having condensate on the evaporator coil?

They probably use the same grade copper for both coils.

There's some corrosion if the condensate is contaminated by VOCs, but nothing the evap doesn't see and it's the evap that would fail first as a result of corrosion.


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## BayouRunner (Feb 5, 2016)

I’m not into the science of it. But on the window units the condenser coils go bad from the bottom up. With no damage to the evaporator coils. Particularly on the less expensive units. 
Basically the copper is still good but the aluminum becomes detached and is very frail. Resulting in higher head pressure
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## supers05 (May 23, 2015)

user_12345a said:


> ...
> You can only buy a 1 bedroom condo for that these days, with outrageous maintenance fees.
> 
> I wish you could buy a tiny townhouse in the gta for 500k.
> ...


Temperature. 

Like all reactions, temperature plays a very important role. The higher the temp, the faster the reaction. On evaps, the colder conditions means that formacary corrosion is a much bigger player. It doesn't play any role on the condenser. The higher temp of the condenser means that galvanic corrosion comes into play with the lifetime of the unit. 

Very good example bayourunner. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> Time to let this thread ride off into the sunset as the comments have been steered way off topic.
> 
> 1.) The original post was simply focused on adding a shade structure to the a/c unit to lower its operating temperature since it sits on the west sided of the house in direct sunlight most of the day especially the hottest portion.
> 
> ...



And you still haven't posted how much water your misting system uses per minute of operation.


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## user_12345a (Nov 23, 2014)

supers05 said:


> Temperature.
> 
> Like all reactions, temperature plays a very important role. The higher the temp, the faster the reaction. On evaps, the colder conditions means that formacary corrosion is a much bigger player. It doesn't play any role on the condenser. The higher temp of the condenser means that galvanic corrosion comes into play with the lifetime of the unit.
> 
> ...


I see. 

So you can extend the life of a window unit by drilling a hole in the bottom to drain the condensate off.

But why would galvanic corrosion be much of an issue?

The water is practically distilled, minus trace chemicals from the air. The PH should be just about neutral, to have corrosion would have to be acidic or basic.


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## supers05 (May 23, 2015)

user_12345a said:


> I see.
> 
> So you can extend the life of a window unit by drilling a hole in the bottom to drain the condensate off.
> 
> ...


It only requires an electrolyte solution. Quite a few things in water will satisfy this. Eg. Salts, and organic material such as DNA, eg. The air is more then dirty enough to cause this. 

https://en.m.wikipedia.org/wiki/Electrolyte?wprov=sfla1

Cheers!


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## SeniorSitizen (Sep 10, 2012)

supers05 said:


> It only requires an electrolyte solution. Quite a few things in water will satisfy this. Eg. Salts, and organic material such as DNA, eg. The air is more then dirty enough to cause this.
> 
> https://en.m.wikipedia.org/wiki/Electrolyte?wprov=sfla1
> 
> Cheers!


The air must have been cleaner back in the *good ole days*.:biggrin2: That's when wives ironed clothes and I caught distilled water for the steam iron. It seemed to work well the 4 years we were in college and poor as snakes. After those good ole days neither the water or the iron was needed.


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## BayouRunner (Feb 5, 2016)

user_12345a said:


> I see.
> 
> So you can extend the life of a window unit by drilling a hole in the bottom to drain the condensate off.
> 
> .




No it’s the opposite. They design them to run with the condensate to keep the pressure down with a slinger fan blade. But as the competition gets worse the coil quality goes down so the price can be lower. It’s seems people will buy the cheaper unit over the quality unit. I can confess now that I have two window units as backups for hurricanes or whatever. I bought the cheap ones lol


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## user_12345a (Nov 23, 2014)

If slinging condensate on the coil shortens its life, than having it drain off should extend lifespan of the coil. But could be harder on the compressor.

I think all of them are pretty junky but the more expensive ones have the circuit board instead of mechanical controls.

How do you know which ones are quality? they all come off the boat from china.


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## supers05 (May 23, 2015)

user_12345a said:


> How do you know which ones are quality? they all come off the boat from china.


They all suck....

People are still getting caught trying go import r22 based models. 

You extend the life of the coil at the expense of lower efficiency and a harder life in the compressor. Unless it's super humid, most are not using the slinger anyways, as the desuperheating loop takes care of it. (just a loop of piping from the discharge, before the condensing coil, in the drip pan. Piping has thicker copper then the coil.) 

Cheers!


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## etsherman (Aug 2, 2011)

digitalplumber said:


> Actually, I kinda know where he is and the area and the size of the homes being built there. Unlike the inner city of Houston, the suburb where he and I are, the homes are large.
> 
> 
> Yes, inner city of Houston will get you a zero lot 2-4000 square foot townhome, 1-3 stories.
> ...


You are spot on digitalplumber ... supers05 should never compare real estate values in Houston, TX to those in Canada. There are totally different sets of metrics used to determine value in each case. I've seen those International House Hunter TV shows where couples were relocating to Canada. For the price, sq. ft. and overall style of the homes and what you get for the dollar there ... I was not impressed ... IJS. There are homes where I live that have guest homes that look better than what's being sold from what I can tell.

In Houston, TX and surrounding suburbs , 500k can buy you a lot of house both new construction as well as in established neighborhoods. Actually, 300k can buy you a lot of house here in Houston, TX and those are not "ghetto" neighborhoods. 

Just like most of the other posts ... supers05 is simply repeating something to make himself seem knowledgeable ... no offense ... just my observation!!!

The three homes below are pretty much in my area of town.


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## supers05 (May 23, 2015)

etsherman said:


> You are spot on digitalplumber ... supers05 should never compare real estate values in Houston, TX.....
> Just like most of the other posts ... supers05 is simply repeating something to make himself seem knowledgeable ... no offense ... just my observation!!!


I was pointing out that prices mean nothing except to a local. Maybe you should read a bit harder. Have a nice day. 

PS. There wasn't a single thing I said that I looked up before hand, except for references. Don't ask for help if you're not interested in it. 

Cheers!


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## etsherman (Aug 2, 2011)

A summary of my findings and test results regarding using misters on your a/c unit.

I decided to invest in an upgraded Infrared Thermometer instead of using the little el-cheapo key chain one that was given to me with a previous tool purchase a while back.

After almost two weeks of misting there is no noticeable mineral build up on the unit's cabinet or the fins. I purchased new brass nozzles that generate an even finer mist than the original plastic ones shown in the video. I also only needed one mister per side but I added 3 to the west side of the unit with two turned off for now since that side gets the most sunlight exposure. 

The unit simply does not run for long periods of time to get the job done. Misters seems to make it work more efficiently. 

I will be adding a Bluetooth Hose Water Timer that can be controlled from my smart phone and it will also precisely measure the amount of water being used by the misters now that I have the ones I want in place.

All seems to be OK for now and IMO the simple misting kit solves my problem.

Thanks,


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## user_12345a (Nov 23, 2014)

Your IR thermometer is inaccurat and you also can't just check one vent and assume the whole mass of the supply air is the same temp.

When the take-off being tested is close to the outlet of the coil, you run a risk of sampling air that hasn't properly mixed.

You also can't tell if there's mineral buildup after only 2 weeks. Plus a coil can look good on the surface but still have issues.


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## etsherman (Aug 2, 2011)

user_12345a said:


> Your IR thermometer is inaccurat and you also can't just check one vent and assume the whole mass of the supply air is the same temp.
> 
> When the take-off being tested is close to the outlet of the coil, you run a risk of sampling air that hasn't properly mixed.
> 
> You also can't tell if there's mineral buildup after only 2 weeks. Plus a coil can look good on the surface but still have issues.


Close enough for what I am doing though!! I will keep a close eye on the coil and fins.

Thanks


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## etsherman (Aug 2, 2011)

My neighbor on the immediate left of my house. Outside a/c unit sits on the west side of the home same as mine. Three months ago installed a new 5 ton Goodman outside a/c unit, new coil, air handler and furnace in the attic. July electric bill in the $400 range with Thermostat set to 76°.

Those air conditioners are designed to be air cooled. Therefore, when you get consecutive 100° plus days like we had here in Houston during the month of July ... They will simply work harder. They are not undersized ... the heat just makes them work harder using more power. If the machine is hot, the air around the machine is hot and it is trying to expel hot air ... then something has to give and provide a temperature difference. That's really all the misters are doing on those extremely hot days!!!


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## digitalplumber (Jul 8, 2011)

etsherman said:


> My neighbor on the immediate left of my house. Outside a/c unit sits on the west side of the home same as mine. Three months ago installed a new 5 ton Goodman outside a/c unit, new coil, air handler and furnace in the attic. July electric bill in the $400 range with Thermostat set to 76°.
> 
> Those air conditioners are designed to be air cooled. Therefore, when you get consecutive 100° plus days like we had here in Houston during the month of July ... They will simply work harder. They are not undersized ... the heat just makes them work harder using more power. If the machine is hot, the air around the machine is hot and it is trying to expel hot air ... then something has to give and provide a temperature difference. That's really all the misters are doing on those extremely hot days!!!


But, what is he paying per kilowatt and how many kilowatts are used? What does he set it at? Halogen or LED bulbs in his home?


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## etsherman (Aug 2, 2011)

digitalplumber said:


> But, what is he paying per kilowatt and how many kilowatts are used? What does he set it at? Halogen or LED bulbs in his home?


Probably .11 per kWh. Stat set at 76° and standard lights nothing heavy drawing power expect the a/c compressor.

Thanks,


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## user_12345a (Nov 23, 2014)

When you put a duct system in an attic in a hot climate and they don't do the best job on duct work, unit possibly not properly charged, *yes the usage will be very high.*

Your own readings who that the duct loss is very high and there could be other problems elsewhere.



As far as capacity and efficiency going down as it gets hotter, the impact of outdoor temp is very modest.

At 75 indoor, 63wb, outdoor 85f, 5 ton has capacity of 55800 btu/hr with 22f drop across the coil.

SHR of 074, this is ratio of capacity used to pull down temp vs capacity needed to dehumidify.

Same indoor conditions, 105f outdoor, same unit has capacity of 51 700 btu/hr with a 22F temperature drop across coil, the same. There's capacity loss, but it's the capacity used to dehumidify that goes down mostly.

SHR - 0.80

The kw at 85f is 4.44 and at 105f, 4.88.

BTU per watt at 85F, 12.6

BTU per watt at 105F, 10.59.

Electricity use increase of 16% for same amount of cooling.

At 65F outdoor, capacity is only a couple around 5000 btu/hr lower and delta-t still sits at 22F, with shr at 0.7. (again, affects dehumidification a lot and sensible capacity, little)

So on a properly operating system, it's impossible for misters to have the impact you're claiming they have on yours.

Also, greyfurnaceman on youtube did a test with misters and found the delta-t actually dropped a little with misters. 

I would trust his testing before yours - using proper equipment and the unit, being properly charged with decent airflow to begin with.

So it's very possible the unit was overcharged and the misters are cutting the head pressure, covering up another problem.

This is simply speculation.

Things don't add up here and we don't have a complete set of data.


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## digitalplumber (Jul 8, 2011)

etsherman said:


> Probably .11 per kWh. Stat set at 76° and standard lights nothing heavy drawing power expect the a/c compressor.
> 
> Thanks,


How many people? Retired? Home all day? Pool?

Electric or Gas Water heater? Gas or electric oven, cook top?

Was his AC system correctly matched? Installed correctly?

How many Big Screen TV's, computers, water softener.....I think there are too many missing variables just to blame it on the AC.


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## etsherman (Aug 2, 2011)

user_12345a said:


> When you put a duct system in an attic in a hot climate and they don't do the best job on duct work, unit possibly not properly charged, *yes the usage will be very high.*
> 
> Your own readings who that the duct loss is very high and there could be other problems elsewhere.
> 
> ...


I disagree on the basis that when the outside temperature drops to the high 80's and below ... the misters really don't make any difference in the performance of the a/c unit (don't even need them on). This is why I am looking for some type of temperature valve to control the supply of water to the misting system only when the outside temp reaches mid 90's and above.

Thanks,


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## digitalplumber (Jul 8, 2011)

I just got my 7/6 thru 8/6 electric bill: 136 bucks, 1512 KW used.


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## user_12345a (Nov 23, 2014)

Being overcharged may only cause a lot of capacity loss in very hot weather, the pressures rise as it gets hotter outside. Plus too much refrigerant can cause liquid stacking in the outdoor coil, reducing the area used to directly condense refrigerant. 

It's like having a undersized coil when you need it the most.

Your results are abnormal, so either your measurements aren't the most accurate, your system has problems beyond those caused by very hot weather, or both.

I'll trust the lab results from the manufacturer and results on the videos I brought up before.


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## etsherman (Aug 2, 2011)

digitalplumber said:


> I just got my 7/6 thru 8/6 electric bill: 136 bucks, 1512 KW used.


Reliant or TXU???

Thanks


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## beenthere (Oct 11, 2008)

etsherman said:


> A summary of my findings and test results regarding using misters on your a/c unit.
> 
> I decided to invest in an upgraded Infrared Thermometer instead of using the little el-cheapo key chain one that was given to me with a previous tool purchase a while back.
> 
> ...



If the return air temp is cooler with the misters on. Either you waited a long time to check the air temps and left the house get cooler to show a better supply temp.


Or, its a sign that your air distribution isn't as perfect as you think it is.


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## digitalplumber (Jul 8, 2011)

etsherman said:


> Reliant or TXU???
> 
> Thanks



Discount Power...I have never used any of the big name folks.


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## user_12345a (Nov 23, 2014)

you have a damn good rate, under 10 cents per kwh.


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## etsherman (Aug 2, 2011)

Straight from my energy provider .... History kWh's billed March to July with High, Average and Low temps. You can clearly see the correlation between the rise in average temperature each month and the rise in kWh's used. This isn't rocket science. Nothing changed in the house as far as our daily routines. The only variable is the progressive rise in outside temperatures. Pretty straight forward to me!!!


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## etsherman (Aug 2, 2011)

user_12345a said:


> you have a damn good rate, under 10 cents per kwh.


Yes it is... I got 13 cents per kWh.


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## user_12345a (Nov 23, 2014)

uh, what are you trying to prove now? Of course your electric use will go up as it gets hotter outside!


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## etsherman (Aug 2, 2011)

beenthere said:


> If the return air temp is cooler with the misters on. Either you waited a long time to check the air temps and left the house get cooler to show a better supply temp.
> 
> 
> Or, its a sign that your air distribution isn't as perfect as you think it is.


LOL ... why would I do that??? I took the readings in successive order. I don't have any reason to trick the numbers beenthere. Just looking for a way to control my energy costs during this hot Houston summer!!!

Thanks,


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## SeniorSitizen (Sep 10, 2012)

Why the large increase in KW usage from March to April with the average and high temperature increase of only 1 degree?


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## etsherman (Aug 2, 2011)

user_12345a said:


> uh, what are you trying to prove now? Of course your electric use will go up as it gets hotter outside!


user_12345a, my August cycle which ended 08/08/2018, the kwh's were approaching 3395 forecasting a $450 bill. This is why I introduced the misters
11 days ago to try and keep it in line with the previous month's usage!!!

Not trying to prove anything really!!! Just trying to get my bill where digitalplumber's bill is, OK!!!

Thanks,


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## etsherman (Aug 2, 2011)

SeniorSitizen said:


> Why the large increase in KW usage from March to April with the average and high temperature increase of only 1 degree?


March was my first period with this provider ... probably has something to do with when they started the counter. March is probably not a full 31 days.

Thanks,


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## digitalplumber (Jul 8, 2011)

Are you setting the temp up when you leave? Where is your TSTAT located?


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## etsherman (Aug 2, 2011)

digitalplumber said:


> Are you setting the temp up when you leave? Where is your TSTAT located?


Stat stays set on 76° for the most part. It is located on the hall above the return vent.

Thanks,


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## beenthere (Oct 11, 2008)

etsherman said:


> LOL ... why would I do that??? I took the readings in successive order. I don't have any reason to trick the numbers beenthere. Just looking for a way to control my energy costs during this hot Houston summer!!!
> 
> Thanks,



Well, your temp readings indicate a good amount of supply air is being drawn directly back into the return then. And that is one of the causes of higher cooling bills in one home over another. Poor air distribution.


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## etsherman (Aug 2, 2011)

beenthere said:


> Well, your temp readings indicate a good amount of supply air is being drawn directly back into the return then. And that is one of the causes of higher cooling bills in one home over another. Poor air distribution.


Opinion ... not necessarily facts. The new variable speed air handler is accountable for that!!! When it's hot outside ... 90° and above ... that air handler pushes a lot of air (CFM's) through the duct work and return vents. I'm actually impressed as to how much air is being circulated/distributed through the entire house compared to my old one speed air handler!!!

Mister System still working as expected and reducing my daily kWh's usage on extremely hot days ... 90° and above. No complaints from me.

Thanks,


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## supers05 (May 23, 2015)

Either you waited a while for the house to cool off, or beenthere is right. Delta T is similar for both cases. (19-20*F)

You have no idea how you're equipment actually works. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Either you waited a while for the house to cool off, or beenthere is right. Delta T is similar for both cases. (19-20*F)
> 
> You have no idea how you're equipment actually works.
> 
> Cheers!


Mister System still working as expected and reducing my daily kWh's usage on extremely hot days ... 90° and above. No complaints from me.

I never claimed to be a Savant in the HVAC industry like you have bestowed upon yourself. Only people like you can evaluate a home's ductwork based on a DIY Chatroom post and make an assessment as to the level of one's knowledge and experience. You know nothing about me so let's keep it that way, OK.

Now, post some pics of your "correct" well designed properly installed HVAC system!!!

Thanks


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## user_12345a (Nov 23, 2014)

> Only people like you can evaluate a home's ductwork based on a DIY Chatroom post and make an assessment as to the level of one's knowledge and experience. You know nothing about me so let's keep it that way, OK.


Based on the temps you've posted, we know your system is running low airflow relative capacity but don't know why.

We also know the results are abnormal and suggest that your measurements are simply not accurate or something is wrong with the system, be it distribution, supply air being pulled into return, low airflow, possible charge issues*

I don't see the point of starting a thread here, asking for advice if you're going to categorically reject the information and advice given and believe what you want to believe.

Why bother?


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## beenthere (Oct 11, 2008)

etsherman said:


> Opinion ... not necessarily facts. The new variable speed air handler is accountable for that!!! When it's hot outside ... 90° and above ... that air handler pushes a lot of air (CFM's) through the duct work and return vents. I'm actually impressed as to how much air is being circulated/distributed through the entire house compared to my old one speed air handler!!!
> 
> Mister System still working as expected and reducing my daily kWh's usage on extremely hot days ... 90° and above. No complaints from me.
> 
> Thanks,



Every brand has a slow ramp up feature that can be used on their VS blowers. And they all go to 100% set CFM at the 10 minute mark during a cooling call, no matter what the outdoor temp is. Unless an additional control has been added.


Since the return air temp drops with the supply air temp drop, you are not getting good air distribution. Many of us know that by what you posted, because we deal with it on a regular basis. VS blowers are not a new thing, so its not new technology to many of us.


Unless the room air temp has dropped, the return air temp should not drop. If it does, than the return is pulling in cooled supply air, and not just room air. No if ands or butts about it.


A good IR imager will show it, I use one on a regular basis to show customers what their distribution system is doing. Most have no idea that it is happening, and have no complaints about it, until shown.


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## etsherman (Aug 2, 2011)

user_12345a said:


> Based on the temps you've posted, we know your system is running low airflow relative capacity but don't know why.
> 
> We also know the results are abnormal and suggest that your measurements are simply not accurate or something is wrong with the system, be it distribution, supply air being pulled into return, low airflow, possible charge issues*
> 
> ...


The generalized comments and assumptions are getting a bit pointless because the original question was never about air flow, air distribution nor return air problems. You and your comrades act as if the a/c techs that installed the air handler/furnace did not perform test to ensure the unit is working properly and according to the manufactures specs including air flow/distribution and return. 

You simply cannot apply your methodology and logic to EVERY a/c installation without first considering all that's involved. Each home will have different layouts that will affect your methods used for testing a/c return air temperature.

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> ..
> You simply cannot apply your methodology and logic to EVERY a/c installation without first considering all that's involved. Each home will have different layouts that will affect your methods used for testing a/c return air temperature.
> 
> Thanks,


Actually it doesn't change anything. Industry standards are fixed. AHRAE sets a lot of them. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> The generalized comments and assumptions are getting a bit pointless because the original question was never about air flow, air distribution nor return air problems. You and your comrades act as if the a/c techs that installed the air handler/furnace did not perform test to ensure the unit is working properly and according to the manufactures specs including air flow/distribution and return.
> 
> You simply cannot apply your methodology and logic to EVERY a/c installation without first considering all that's involved. Each home will have different layouts that will affect your methods used for testing a/c return air temperature.
> 
> Thanks,



The manufacturers only have 3 basic specs for air flow and distribution, and that is their temp rise range, TESP, and combustion set up on gas and oil furnaces.


Your set ups TESP is well above the manufacturers .5" ESP/TESP rating. Like it or not, I can tell by your return connection. Along with the distribution boxes you drew.


Very very very few residential systems operate at the manufacturers specs. Why, TIME and MONEY. It takes more time, and cost more money, money that the average home owner, and general contractor don't want to pay.


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## etsherman (Aug 2, 2011)

beenthere said:


> Every brand has a slow ramp up feature that can be used on their VS blowers. And they all go to 100% set CFM at the 10 minute mark during a cooling call, no matter what the outdoor temp is. Unless an additional control has been added.
> 
> 
> Since the return air temp drops with the supply air temp drop, you are not getting good air distribution. Many of us know that by what you posted, because we deal with it on a regular basis. VS blowers are not a new thing, so its not new technology to many of us.
> ...


beenthere, I thought I had explained this somewhere in a previous post. The entire west side of my home is well insulated (ceilings and walls) and there are NO windows on that wall. There is one roof skylight over the master bathroom which is tinted and has a solar screen installed from the inside. There are rooms and a hall way and the air handler/furnace on that western side of the home that gets zero sunlight or sun exposure. The return and thermostat are located on a hall next to a utility room and hall bath that gets no sun or heat exposure. Those two rooms (utility and bath) are sitting directly under the air handler literally (it is all of an 18 inch duct run from the plenum to the vent in both cases) and are an arms length from the a/c return intake. 

Now, with 52° air going into the utility room and hall bath all day long those rooms stay really cool because there is no heat or hot air going into them and no windows. When the a/c kicks on and that blower kicks in ... it is pulling that air directly from the two rooms that are cooler than the temperature on the hall way where the thermostat is. This is why with the thermostat set to 76°, 52° air going into those rooms .... the return air temp is at 72° (exactly what I would expect to happen given the layout). The draw that the air handler has is very strong once it gets going ... If the doors to those rooms are lift cracked open ... the air handler will shut them ... OK. This is why one of your comrades made the assumption that I was purposely letting the unit run to change the intake air temp ... NO ... it simply pulls that cool air first directly from those two interior rooms that are well insulated with no windows.

I have full confidence in the work that the a/c techs performed when I changed out my air handler/furnace a few months ago. I am also totally satisfied with the performance of this equipment in terms of air flow/distribution. My original post was directed to lowering the OUTSIDE ambient temperature around the a/c unit on extremely hot days here in Houston. This was done by simply connecting 4 inexpensive misters to it with an irrigation valve. The kWh's went down and I'm happy.

Thanks for your input!!!


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## beenthere (Oct 11, 2008)

What you just described is a poor air distribution set up. Those 2 rooms should not get enough air to change the air temp going into the return. So your HVAC companies senior rep didn't balance out the system nearly as well as you claimed. 



Your duct system is not nearly as perfect as you want to think it is.


The draw of a return is never suppose to be strong, let alone really strong.


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## supers05 (May 23, 2015)

etsherman said:


> beenthere, I thought I had explained this somewhere in a previous post. The entire west side of my home is well insulated (ceilings and walls) and there are NO windows on that wall. There is one roof skylight over the master bathroom which is tinted and has a solar screen installed from the inside. There are rooms and a hall way and the air handler/furnace on that western side of the home that gets zero sunlight or sun exposure. The return and thermostat are located on a hall next to a utility room and hall bath that gets no sun or heat exposure. Those two rooms (utility and bath) are sitting directly under the air handler literally (it is all of an 18 inch duct run from the plenum to the vent in both cases) and are an arms length from the a/c return intake.
> 
> Now, with 52° air going into the utility room and hall bath all day long those rooms stay really cool because there is no heat or hot air going into them and no windows. When the a/c kicks on and that blower kicks in ... it is pulling that air directly from the two rooms that are cooler than the temperature on the hall way where the thermostat is. This is why with the thermostat set to 76°, 52° air going into those rooms .... the return air temp is at 72° ...


You just made it fact. You're pulling supply air into the return air. This is a poor setup. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> You just made it fact. You're pulling supply air into the return air. This is a poor setup.
> 
> Cheers!


It's not supply air ... it is simply well cooled and preserved air that originally started out at 52° in a insulated room right next to the return. The temperature in those rooms is not going to rise up to 76° ... that's impossible and I don't expect it to. The air handler is going to naturally pull that air first simply because of the rooms proximity to the return vent and the power of its suction. 

And, no I'm not going to relocate the HVAC return in the house!!!

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> It's not supply air ... it is simply well cooled and preserved air that originally started out at 52° in a insulated room right next to the return. The temperature in those rooms are not going to rise up to 76° ... that's impossible and I don't expect it to. The air handler is going to naturally pull that air first simply because of the rooms proximity to the return vent and the power of its suction.
> 
> And, no I'm not going to relocate the HVAC return in the house!!!
> 
> Thanks,


But you'll waste water on misters. We are talking about raw efficiency of your unit, in the end influencing your electricity bill. 

Anyways, a better system is not to relocate the return. It is to add more, evenly distributing the returns around the house. Ideally in every room. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> But you'll waste water on misters. We are talking about raw efficiency of your unit, in the end influencing your electricity bill.
> 
> Anyways, a better system is not to relocate the return. It is to add more, evenly distributing the returns around the house. Ideally in every room.
> 
> Cheers!


OR ... simply closing the doors to those to the utility room and bath that are located within an arms length of the a/c return!!!

Thanks ...


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## supers05 (May 23, 2015)

etsherman said:


> OR ... simply closing the doors to those to the utility room and bath that are located within an arms length of the a/c return!!!
> 
> Thanks ...


If it's so easy, then why are your numbers so dramatic? I would expect 72* return air on floor returns, not ceiling returns. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> It's not supply air ... it is simply well cooled and preserved air that originally started out at 52° in a insulated room right next to the return. The temperature in those rooms are not going to rise up to 76° ... that's impossible and I don't expect it to. The air handler is going to naturally pull that air first simply because of the rooms proximity to the return vent and the power of its suction.
> 
> And, no I'm not going to relocate the HVAC return in the house!!!
> 
> Thanks,



Can't pull more air out of those rooms then is put into them. So its not pulling the air out of those rooms first. Its that those 2 rooms are getting too much air. Other wise the return air temp wouldn't drop so much lower than the room air temp of the rest of the house.


Your air distribution set up, isn't as good as that senior rep lead you to believe. Its not horrible, just not perfect like you think.


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## supers05 (May 23, 2015)

etsherman said:


> ... This is why with the thermostat set to 76°, 52° air going into those rooms .... the return air temp is at 72° ...


FYI, we aim for a max spread of 2*f within a zone. 

With my computer off, my house maintains that, and it only has builders grade ductwork. (i haven't had the time to replace some of it yet.) 

Cheers!


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## etsherman (Aug 2, 2011)

beenthere said:


> Can't pull more air out of those rooms then is put into them. So its not pulling the air out of those rooms first. Its that those 2 rooms are getting too much air. Other wise the return air temp wouldn't drop so much lower than the room air temp of the rest of the house.
> 
> 
> Your air distribution set up, isn't as good as that senior rep lead you to believe. Its not horrible, just not perfect like you think.


Nope ... Assumption ... Not Fact. It's really not that complicated!!!

The readings below were taken a few minutes ago when I heard the a/c unit turn on.

I closed the door to the right of the a/c return which is the interior utility room sitting directly under the air handler/furnace and plenum box. 

Thermostat set on 76°, door was previously closed to the utility room. Temp on the hall rose to 77° as displayed on the wall thermostat and the air temp around the a/c return grille is also reading 77°. 

Also, those interior rooms are not getting too much air as the baffles inside the ducts at the vents have been adjusted properly. Those rooms are interior, well insulated with no exposure to sunlight or windows. Therefore, they simply retain the cool air that is vented into them. If I open that door ... the return will simply pull that cool air first!!! 

Oh boy ... We got the popcorn ready waiting for the next assessment of this one. Keep in mind, my neighbor worked on the a/c systems used on the Space Shuttles at NASA, OK. :wink2:


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## supers05 (May 23, 2015)

Why on earth do you have a floor return when your unit is in the attic? You're primary usage is cooling, not heating. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> Nope ... Assumption ... Not Fact. It's really not that complicated!!!
> 
> The readings below were taken a few minutes ago when I heard the a/c unit turn on.
> 
> ...



Well, then your neighbor must have a mister system too, since he's so bright. lol


If your system was truely as well balanced as you want to claim. Then those rooms wouldn't have enough air flow to effect the return air temp when the doors are open. They are interior rooms with too much air flow to them.


Plus, you said you have the thermostat set to 76. With those doors closed, you are now showing yourself that those rooms having too much air flow, are actually causing the house temp to be warmer than 76. Or else the return air temp wouldn't be 77.


You keep proving your concepts of how well your system is balanced is wrong.


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## supers05 (May 23, 2015)

etsherman said:


> ... Keep in mind, my neighbor worked on the a/c systems used on the Space Shuttles at NASA, OK. :wink2:


Those are completely different as your condensing unit requires gravity and air. Neither available in orbit. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Why on earth do you have a floor return when your unit is in the attic? You're primary usage is cooling, not heating.
> 
> Cheers!


It works and has been working for the last 33 years. House was built by a custom home builder with lots of experience. No complaints here.

Thanks ...


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## etsherman (Aug 2, 2011)

beenthere said:


> Well, then your neighbor must have a mister system too, since he's so bright. lol
> 
> 
> If your system was truely as well balanced as you want to claim. Then those rooms wouldn't have enough air flow to effect the return air temp when the doors are open. They are interior rooms with too much air flow to them.
> ...


Nope, the stat will let the air temp rise 1 or 2 degrees above the setting before it turns on. That's how it works!!! I'm cool!!!

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> It works and has been working for the last 33 years. House was built by a custom home builder with lots of experience. No complaints here.
> 
> Thanks ...


Very strange that a custom home builder would put a floor return for your location. I really would like to know his logic. It's lowering your efficiency quite a bit. A good custom builder would have had the hvac drawn up by a designer. No designer or engineer that I know would put their name on that system. 

(electrical, plumbing, structural, interior design all gets designed by designers or engineer's on custom homes here.) 

Cheers!


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## BayouRunner (Feb 5, 2016)

Very common here in the south during that time period. Two nice things about it. You don’t need a ladder to change a filter. Makes for a very quiet system as well. Really don’t see it any more though. It was just that era. I cringe at the 16 inch flex at the top of that big return though


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## supers05 (May 23, 2015)

BayouRunner said:


> Very common here in the south during that time period. Two nice things about it. You don’t need a ladder to change a filter. Makes for a very quiet system as well. Really don’t see it any more though. It was just that era. I cringe at the 16 inch flex at the top of that big return though


I understand the ladder part. Any noise is just bad design though. For AC, it significantly lowers efficiency. (increases efficiency for heatimg though.) 

The efficiency of the compressor is more related to suction pressure then discharge pressure. The lower air temp causes lower suction pressures, which significantly effect efficiency. For example, at refrigerator temps, the compressor usually has a COP of about 1. (Same thing with Heat Pumps in the winter.) You can lower the head pressure, but barely gain on COP. The goal of AC designers is to keep the suction as high as possible, while still cooling and dehumidifing. (if dehumidification is desired.) That's why mini-splits do so well. 

Cheers!


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## etsherman (Aug 2, 2011)

BayouRunner said:


> Very common here in the south during that time period. Two nice things about it. You don’t need a ladder to change a filter. Makes for a very quiet system as well. Really don’t see it any more though. It was just that era. I cringe at the 16 inch flex at the top of that big return though


Yep ... He builds homes all over Texas and one of the top builders in the state. Professional builder not some run of the mill contractor!!

There are pros and cons to doing it either way!!! Just my opinion. I really don't have a problem or complaint with air flow, distribution, hot & cold spots in summer or winter. The air inside is always comfortable all throughout the house. It is a single story so I don't have the problem of cool downstairs and warm upstairs during those hot summer months. 

https://www.perryhomes.com/new-homes-houston/aliana/174/

Thanks ...


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## etsherman (Aug 2, 2011)

supers05 said:


> Very strange that a custom home builder would put a floor return for your location. I really would like to know his logic. It's lowering your efficiency quite a bit. A good custom builder would have had the hvac drawn up by a designer. No designer or engineer that I know would put their name on that system.
> 
> (electrical, plumbing, structural, interior design all gets designed by designers or engineer's on custom homes here.)
> 
> Cheers!


Sure .... contact them here. They will answer your question better than I can.

https://www.perryhomes.com/new-homes-houston/aliana/174/

Thanks ...


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## BayouRunner (Feb 5, 2016)

supers05 said:


> I understand the ladder part. Any noise is just bad design though. For AC, it significantly lowers efficiency. (increases efficiency for heatimg though.)
> 
> The efficiency of the compressor is more related to suction pressure then discharge pressure. The lower air temp causes lower suction pressures, which significantly effect efficiency. For example, at refrigerator temps, the compressor usually has a COP of about 1. (Same thing with Heat Pumps in the winter.) You can lower the head pressure, but barely gain on COP. The goal of AC designers is to keep the suction as high as possible, while still cooling and dehumidifing. (if dehumidification is desired.) That's why mini-splits do so well.
> 
> Cheers!




I get it. If it was my home the return would be in the ceiling with square duct all the way to the return and the existing chase would become another closet for my bride to store more stuff. (This is a constant battle between my wife and I) As she keeps everything. But I take it with good humor. Anyway it was designed back in the 80’s. That’s just the way they were done. Units were generally oversized, insulation r11 in walls, r19 in attics. Just the way it was done. A lot of those returns aren’t even sealed inside. A lot more attention to design and power consumption now. 


Sent from my iPhone using Tapatalk


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## supers05 (May 23, 2015)

etsherman said:


> Sure .... contact them here. They will answer your question better than I can.
> 
> https://www.perryhomes.com/new-homes-houston/aliana/174/
> 
> Thanks ...


Considering their size, they probably have multiple teams. Who knows who they had lead that construction. They won't remember a house unless it was recent. On custom homes, the original home owner gets a significant say, whether good or bad. Far too often the interior designer gets way to much influence, and the utilities suffer from it. (poor ductwork, difficult plumbing, electrical panels stuffed into tight spots. They meet code, but are definitely not optimal.) 

PS. I just looked through their site. They are more of a turn-key unique house developer, rather then a custom home builder. I looked at some of their floor plans. Some are OK, but others are terrible. I can't imagine that installing the utilities would be very easy in some of those designs. 

Cheers!


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## supers05 (May 23, 2015)

BayouRunner said:


> ... would become another closet for my bride to store more stuff. ...


So very important! If she's happy, who cares about everything else! 

Cheers!


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## etsherman (Aug 2, 2011)

BayouRunner said:


> I get it. If it was my home the return would be in the ceiling with square duct all the way to the return and the existing chase would become another closet for my bride to store more stuff. (This is a constant battle between my wife and I) As she keeps everything. But I take it with good humor. Anyway it was designed back in the 80’s. That’s just the way they were done. Units were generally oversized, insulation r11 in walls, r19 in attics. Just the way it was done. A lot of those returns aren’t even sealed inside. A lot more attention to design and power consumption now.
> 
> 
> Sent from my iPhone using Tapatalk


Yep, I agree!!


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## etsherman (Aug 2, 2011)

supers05 said:


> Considering their size, they probably have multiple teams. Who knows who they had lead that construction. They won't remember a house unless it was recent. On custom homes, the original home owner gets a significant say, whether good or bad. Far too often the interior designer gets way to much influence, and the utilities suffer from it. (poor ductwork, difficult plumbing, electrical panels stuffed into tight spots. They meet code, but are definitely not optimal.)
> 
> PS. I just looked through their site. They are more of a turn-key unique house developer, rather then a custom home builder. I looked at some of their floor plans. Some are OK, but others are terrible. I can't imagine that installing the utilities would be very easy in some of those designs.
> 
> Cheers!


Back in the 80's they were custom building more of the executive series homes ... all brick including a full masonry fireplace/chimney and custom trim work all throughout the interior including wood floors. Now, they have watered that down to keep up with competition in the expanding markets around Houston. They still build a nice home though.


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## etsherman (Aug 2, 2011)

Ok, serious question now that we are all in agreement water misters (if installed and properly maintained) can make your outside a/c unit function significantly more efficiently on EXTREMELY HOT & DRY days like we get here in Houston, TX during the summer months. The final test will be the comparison of August billing cycle kWh's usage (which is really a full 30 days July usage without misters) and September billing cycle kWh's usage (which is a full 30 days August usage with misters) ending September 7th.

Now, the real question that I have for the "Savants" on this thread (supers505, beenthere and user_12345a) is as follows since I have absolutely no experience with this item. I will be making an addition to this home in the near future approx. 800 sq. ft. as shown in the drawing below. Same flow meaning single story attached to the existing structure, brick exterior walls, spray foam insulation and no windows on the west side of the addition. Addition includes 2 bedrooms, large bath, half bath and relocation of the laundry room thus using the existing laundry room for a walk in pantry and other storage. Also converting one bedroom to a study and extending the hall to the back addition. Existing library is really my wife's formal living room!!!. The contractor is offering to power the addition totally off of solar power instead of connecting it to the existing electrical panel thus giving the utility company even more $$$$. I like solar power and believe in it as I was convinced to use a solar powered gate opener to open my 850+ lb. steel driveway gate that spans 14 ft. across. I am impressed at how well it performs and has never had any problems since installation 4 years ago. 

My question is regarding using solar to power a HVAC system to keep the 800 sq. ft. addition properly heated and cooled since I will want to do it the "correct" way!!!. I know a/c compressors draw a lot of amps thus requiring a 240 v line. Are there HVAC systems designed to work with solar? If so, are these setup like a traditional system with a outside unit and inside air handler, etc.? Or, are these systems designed to be placed in each individual room in the addition? I've never seen one so any advice and information will be appreciated. 

Thanks,


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## user_12345a (Nov 23, 2014)

Solar is very expensive for the amount of power you get. But you would have to price it out in your area and see how cost effective it is.

You may only get like 6 or 7 kwh per day for every 1 kw installed.

There's grid dependent solar and solar with storage, with grid or generator backup. Solar with storage would be tricky when powering large loads.

The only real value in grid dependent solar is offsetting the electric bills. If the power goes out, you still lose power, no backup.

Probably just best to build the addition to be as energy efficient as possible, with R20+ walls, R50+ attic, low-e windows and overhangs to provide good shading. 

Have all the ducts in the conditioned space, air handler or furnace in a utility closet. Or use mini-splits.


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## BayouRunner (Feb 5, 2016)

I don’t think solar would be a feasible option for the ac. The power to start the compressor initially would be the issue. If it were an inverter compressor like a mini split or some of the high seer units it would start ok but you would need a pretty good battery backup to run it. Then you would need a larger panel setup as well. If you wanted to keep the solar option I would just run normal
power to your hvac system and use solar for the rest. Just my opinion, others may not agree 


Sent from my iPhone using Tapatalk


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## supers05 (May 23, 2015)

etsherman said:


> Ok, serious question now that we are all in agreement water misters (if installed and properly maintained) ...
> Now, the real question that I have for the "Savants" on this thread (supers505, beenthere and user_12345a) ...


Why would we even bother. You don't listen to us anyways. It's simple engineering. I'm more content in finding the problems with your posts. I had started genuinely trying to help i get nothing from this forum. 



user_12345a said:


> ...
> You may only get like 6 or 7 kwh per day for every 1 kw installed.
> ...


And thats for the south. We only get an average of roughly 3kwh/ day, depending on the site and setup. 

Cheers!


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## BayouRunner (Feb 5, 2016)

User having the ducts in a conditioned space is not really an option here as basements are few and far between. I’ve only seen one here in Baton Rouge the last 40 years. Sometimes you will see a unit with a drop down ceiling and chase in the hallway. But it’s not appealing to the homes that are being designed. I get what your saying but I just don’t see it happening. Up in the attic is where they will go. The foam addition will allow the attic install to have very little temp difference 


Sent from my iPhone using Tapatalk


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## supers05 (May 23, 2015)

BayouRunner said:


> User having the ducts in a conditioned space is not really an option here as basements are few and far between. I’ve only seen one here in Baton Rouge the last 40 years. Sometimes you will see a unit with a drop down ceiling and chase in the hallway. But it’s not appealing to the homes that are being designed. I get what your saying but I just don’t see it happening. Up in the attic is where they will go. The foam addition will allow the attic install to have very little temp difference
> 
> 
> Sent from my iPhone using Tapatalk


It's all about design. Either you leave 8" of space between the ceiling and joists, or you plan it really well. Many houses in the north here don't have basements, and are slab on grade like you guys. All of their ductwork is hidden very well on most home that aren't the most basic. 

Cheers!


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## user_12345a (Nov 23, 2014)

Yes, you can leave more space or put in bulkheads.

Can do high velocity if there isn't much space.

If ducts can only be in the attic, you foam the roof, put a subfloor and make the attic a conditioned space.


Or, just put mini-splits.

The way hvac is normally done in the south sounds awful, and it explains why electric use is so high down there.

The nice thing about getting an addition done is that the owner can have control over how things are done.


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## etsherman (Aug 2, 2011)

user_12345a said:


> Solar is very expensive for the amount of power you get. But you would have to price it out in your area and see how cost effective it is.
> 
> Probably just best to build the addition to be as energy efficient as possible, with R20+ walls, R50+ attic, low-e windows and overhangs to provide good shading.


Finally we agree on something 100% ... my thinking exactly!!!:smile:

Thanks ...


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## user_12345a (Nov 23, 2014)

Yes - you may be surprised at how little tonnage it needs when built to be energy efficient and ducts in a conditioned space.

You may only need 1.5 tons when the norm in your area may be 2; make sure a load calculation gets done. (in my area it would probably only need 1 ton)


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## etsherman (Aug 2, 2011)

BayouRunner said:


> I don’t think solar would be a feasible option for the ac. The power to start the compressor initially would be the issue. If it were an inverter compressor like a mini split or some of the high seer units it would start ok but you would need a pretty good battery backup to run it. Then you would need a larger panel setup as well. If you wanted to keep the solar option I would just run normal
> power to your hvac system and use solar for the rest. Just my opinion, others may not agree
> 
> 
> Sent from my iPhone using Tapatalk


We are home folks BayouRunner ... I am originally from Belle Rose, LA down on Bayou Lafourche south of Donaldsonville, LA on Hwy 1. Been in Houston since the early 1980's. There is a big difference in the way home builders in Houston build compared to those that I am used to in So. Louisiana but my father always said ... when in Rome ... do as the Romans!!! LOL

I agree with your comments also ... I am assuming the contractor meant what you said with this option to run the addition off of solar. I just can't see running a HVAC from solar power but I will continue to research and confirm with him the exact specs the closer I get to starting the project. Construction labor costs here is very expensive. The price and range from $150 per sq. ft. upwards to $250. I think that turnkey but still. That addition is going to run me about $120K ... just a bit lower than what I paid for the entire home in 1985!!!


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## BayouRunner (Feb 5, 2016)

user_12345a said:


> Yes, you can leave more space or put in bulkheads.
> 
> Can do high velocity if there isn't much space.
> 
> ...




My bill is not bad. 2400 sq ft. $159 prior month, $197 this month (34 days). Includes our water (we have a well) all electric Home. I do have a 20 seer heat pump though. Some ducts in ceiling, some in attic. Some above the wrap around porch. Very little attic space but air handler is in attic. R19 in attic, foam underneath. I forget what the walls are. Maybe R15 27 years old. Temp set to 70 degrees constant. This month and next month will be my highest bills


Sent from my iPhone using Tapatalk


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## BayouRunner (Feb 5, 2016)

Head through Belle chase every time I go to fish Venice. The homes in Baton Rouge are compatible to Houston. The homes in the 80’s in the higher end subdivisions. Houston had such a growth explosion back then. I was in your neck of the woods for Harvey. Spent roughly 6 days doing rescues. I have family there as well. 


Sent from my iPhone using Tapatalk


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## BayouRunner (Feb 5, 2016)

Wrong city lol. Head that way when I go to Grand Isle!


Sent from my iPhone using Tapatalk


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## etsherman (Aug 2, 2011)

user_12345a said:


> Yes, you can leave more space or put in bulkheads.
> 
> Can do high velocity if there isn't much space.
> 
> ...


I'll agree with that user_12345a ... in that our attic space where the HVAC systems are typically located should be a more condition environment considering the temperatures we get here and what the system is trying to accomplish. Just seems logical that that space would be insulated to make the unit & duct work perform a lot more efficiently.


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## supers05 (May 23, 2015)

etsherman said:


> I'll agree with that user_12345a ... in that our attic space where the HVAC systems are typically located should be a more condition environment considering the temperatures we get here and what the system is trying to accomplish. Just seems logical that that space would be insulated to make the unit & duct work perform a lot more efficiently.


Then do it. Spray foam the roof deck. You won't like the price though. 

Cheers!


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## user_12345a (Nov 23, 2014)

There are many different options to avoid having ducts in a very hot space and spray foaming the roof is just one of them.

Explore all options and associated costs.

I would go for mini-splits before ever looking at an attic system.


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## etsherman (Aug 2, 2011)

BayouRunner said:


> Head through Belle chase every time I go to fish Venice. The homes in Baton Rouge are compatible to Houston. The homes in the 80’s in the higher end subdivisions. Houston had such a growth explosion back then. I was in your neck of the woods for Harvey. Spent roughly 6 days doing rescues. I have family there as well.
> 
> 
> Sent from my iPhone using Tapatalk


LOL ... still wrong city ... not Belle Chase ... Belle Rose, LA. Just south of Baton Rouge on LA 1. See map


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## supers05 (May 23, 2015)

user_12345a said:


> Can do high velocity if there isn't much space.
> ...


It's great for retrofits in very old homes, like downtown. You need to sound insulate the mechanical room, as the blower can be loud. Every seem has to be duct sealed well. They just use regular ECMs but with slightly smaller wheels to stay within ratings. They push 2-3"wc. I don't like installing them in me construction. 

Cheers!


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## user_12345a (Nov 23, 2014)

from what i know the efficiency ratings aren't as good as for conventional velocity systems, if duct losses are avoided it's worth it.


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## supers05 (May 23, 2015)

user_12345a said:


> from what i know the efficiency ratings aren't as good as for conventional velocity systems, if duct losses are avoided it's worth it.


That's the problem, you double your blower energy usage. Even on circulate mode. 

Cheers!


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## etsherman (Aug 2, 2011)

BayouRunner said:


> My bill is not bad. 2400 sq ft. $159 prior month, $197 this month (34 days). Includes our water (we have a well) all electric Home. I do have a 20 seer heat pump though. Some ducts in ceiling, some in attic. Some above the wrap around porch. Very little attic space but air handler is in attic. R19 in attic, foam underneath. I forget what the walls are. Maybe R15 27 years old. Temp set to 70 degrees constant. This month and next month will be my highest bills
> 
> 
> Sent from my iPhone using Tapatalk


That's about where I am trying to get my bill to level out. My home is also 2400 sq. ft. My July will was heading north of $400 which is why I installed the misters on my a/c unit. Originally started out trying to shade it but quickly discovered that was not going to make any difference!!! Misters seems to be working great on these extreme hot days!!!


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## supers05 (May 23, 2015)

BayouRunner said:


> User having the ducts in a conditioned space is not really an option here as basements are few and far between. I’ve only seen one here in Baton Rouge the last 40 years. Sometimes you will see a unit with a drop down ceiling and chase in the hallway. But it’s not appealing to the homes that are being designed. I get what your saying but I just don’t see it happening. Up in the attic is where they will go. The foam addition will allow the attic install to have very little temp difference
> 
> 
> Sent from my iPhone using Tapatalk





supers05 said:


> It's all about design. Either you leave 8" of space between the ceiling and joists, or you plan it really well. Many houses in the north here don't have basements, and are slab on grade like you guys. All of their ductwork is hidden very well on most home that aren't the most basic.
> 
> Cheers!


It took a while. Still haven't found all of the photos yet. 









The lower ducts are for the HRV. That chase rounds the whole room, with a reveal. The HVAC is above it. 8" with 3" take offs. Those HRV pipes on the wall for spray foamed in, with the second coat. The ceiling got sound insulation spray. 









You can see the ducting snaking it's way through the bathroom here. 









It's a high V system. Didn't want to do it, but we didn't have enough space, as the drawings called for tight ceilings. So we had to stick with the designer's plans. We did change the primary heating to the in-floor heating that we installed. It was supposed up be only comfort heating, but we wanted some backup heat as this place can get cold. It definitely made a difference for the crews during winter. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Why would we even bother. You don't listen to us anyways. It's simple engineering. I'm more content in finding the problems with your posts. I had started genuinely trying to help i get nothing from this forum.
> 
> 
> 
> ...


LOL ... supers05, wrong again ... You were the one that said shading the a/c unit is not going to make any difference and I realized what you were saying was true. I listened and went for the option of adding misters to the a/c unit. Your expert "Savant" knowledge led me in the right direction!!! :biggrin2:


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## etsherman (Aug 2, 2011)

supers05 said:


> It took a while. Still haven't found all of the photos yet.
> 
> 
> 
> ...


I can see where that duct work can be a lot more efficient than having those runs in the hot attic!!! Contractors here are just going to do it the shortest way possible for THEM. Unit in the attic and punch down through the sheetrock ceilings. It is pretty much the acceptable standard here!!!

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> I can see where that duct work can be a lot more efficient than having those runs in the hot attic!!!
> 
> Thanks,


It's hard to see but that ceiling has 7" of spray foam. Some of the lineset is there forever now. 

Cheers!


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## supers05 (May 23, 2015)

etsherman said:


> LOL ... supers05, wrong again ... You were the one that said shading the a/c unit is not going to make any difference and I realized what you were saying was true. I listened and went for the option of adding misters to the a/c unit. Your expert "Savant" knowledge led me in the right direction!!! :biggrin2:


We also told you that you'd ruin your coil, and you dismissed that. We said that you may have some airflow problems, that you seemed to add facts to support, and you categorically dismissed that too. That's even after we explained how it effects the very reason why you started this thread. 

Then you get onto the insults. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> We also told you that you'd ruin your coil, and you dismissed that. We said that you may have some airflow problems, that you seemed to add facts to support, and you categorically dismissed that too. That's even after we explained how it effects the very reason why you started this thread.
> 
> Then you get onto the insults.
> 
> Cheers!


What insults ... please explain!!!

I don't think any of my posts were insults ... but if it came off as being so ... I do apologize. Sorry for the confusion!!!

Thanks,


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## BayouRunner (Feb 5, 2016)

supers05 said:


> It took a while. Still haven't found all of the photos yet.
> 
> 
> 
> ...




I like it and agree. But there is rarely that much communication between the homeowner, builder and hvac contractor. We rarely do new construction any more as it is cut throat. Although my son is in the business as well and he wants it. I’m retiring soon I hope and that will change at that point. He’s tried to get me in on the new subdivisions but I don’t really like working for contractors. I went on two units last weeks where the lowball contractors did the jobs. One only a few months old. Return was done like the original poster flex duct with the return. All single ducts with no dampers. Insulation falling off 3 y’s. One room didn’t have a duct. More of a very wide hallway but was very warm. I asked contractor if an inspection had been done, he said yes but I’m Leary. Anyway I bid what I thought would be needed to correct it. Never heard back. The homeowners ac had froze up and they couldn’t get the original installer out for a few days was how I got involved by recommendation. Second one from what I understood the unit was started without the service valves being opened from what I understood. Don’t know how long it was like that. Ran for about a year or so but was barely cooling when I checked it. Had to have compressor replaced. Another out of town service company that they couldn’t get back to fix it.


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## beenthere (Oct 11, 2008)

Solar as a stand alone/island system for an addition still isn't a great idea. Even an inverter compressor is going to have a good wattage draw for long periods of time. And since best battery life span for solar is not draining the batteries down lower than 50%, you would need a large area for the batteries. Plus checking their health on a regular basis. 



A non inverter based A/C would need even more KW storage so that it could start the compressor during the night time without draining the batteries in just a few cycles of the A/C.


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## supers05 (May 23, 2015)

etsherman said:


> Just like most of the other posts ... supers05 is simply repeating something to make himself seem knowledgeable ...



Cheers!


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## supers05 (May 23, 2015)

etsherman said:


> LOL ... supers05, wrong again ... You were the one that said shading the a/c unit is not going to make any difference and I realized what you were saying was true. I listened and went for the option of adding misters to the a/c unit. Your expert "Savant" knowledge led me in the right direction!!! :biggrin2:


Found more examples. 

We told you that IR guns are inaccurate, especially on condenser coils, and similar surfaces. You continued to use it. It's a long thread, so maybe I'm forgetting, but I think you mentioned getting A better ir gun, which won't help. 

Then there was something about generalized comments are pointless. We all typed every post here. No copy and pasting. It was all relevant to you and your thread. We gain nothing from this forum, except maybe learning something here and there. Mostly on how other places do things. 

Cheers!


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## supers05 (May 23, 2015)

BayouRunner said:


> I like it and agree. But there is rarely that much communication between the homeowner, builder and hvac contractor. We rarely do new construction any more as it is cut throat. ... service company that they couldn’t get back to fix it.


It's common here. I don't do subdivisions. I won't work for a developer. They wouldn't pay what I want anyways. These are actual custom homes, not just finishing. They can be challenging, as changes often happen as the home owner sees the progress. I can't afford the copper in some of the equipment rooms, let alone the house/cottage. Redoing already completed work can get expensive and tiresome. There's always miscommunication between the designers, architect, and trades. A good general contractor/ or home owner, negotiates all of the problems with everyone. 

Cheers!


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## user_12345a (Nov 23, 2014)

I think the codes are better and more strictly enforced here in ontario than in the southern us so things are done better.

In new houses systems have to be engineered properly, the duct joints have to be sealed, equipment commissioned.

ECM motors in the equipment, ruling out a lot of cheap builder's grade furnaces.

They require condensing hot water tanks and drain heat recovery exchangers too.

I think what they do in texas in new construction would never be accepted in most canadian provinces.


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## supers05 (May 23, 2015)

user_12345a said:


> ...
> They require condensing hot water tanks and drain heat recovery exchangers too.
> 
> I think what they do in texas in new construction would never be accepted in most canadian provinces.


There's also the problem that things would freeze in our attics. Lol. (along with half of the US.) 

Many places are still good with 80% hot water tanks. Municipalities are changing that, little by little. The waste water HXrs are too expensive. I'm going to make one myself, for my house. I suspect it'll be a fraction of the price. 

With building codes here, you can heat a fair sized house with just 60-80k btu. The house in the pictures above was idling at 55-65k btu during the coldest days of construction. It's a large place, but built above code. 1000 sq house from the 50s can be heated with 40k btu with just new windows. Lol. That building envelope is so important. 



Cheers!


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## user_12345a (Nov 23, 2014)

Forget new construction, you can heat a 1980s 3000+ sq ft house with a modern 80k furnace and 2000-2500 sq ft with 60k.


I know from being in a 3500 sq ft house (wasn't mine - was family home actually), had a 79 000 btu output rated natural draft furnace and never had insufficient heat despite using setback stat and leaky fireplace dampers.

If built now that type of house could probably do it on 60 to 70k output.


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## supers05 (May 23, 2015)

user_12345a said:


> Forget new construction, you can heat a 1980s 3000+ sq ft house with a modern 80k furnace and 2000-2500 sq ft with 60k.
> 
> 
> I know from being in a 3500 sq ft house (wasn't mine - was family home actually), had a 79 000 btu output rated natural draft furnace and never had insufficient heat despite using setback stat and leaky fireplace dampers.
> ...


If built above building code, (spray foam) you'd likely be good with a 40k btu. 

Cheers!


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## etsherman (Aug 2, 2011)

supers05 said:


> Cheers!


LOL ... Just poking at you ... nothing personal!!:smile:


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## etsherman (Aug 2, 2011)

supers05 said:


> Found more examples.
> 
> We told you that IR guns are inaccurate, especially on condenser coils, and similar surfaces. You continued to use it. It's a long thread, so maybe I'm forgetting, but I think you mentioned getting A better ir gun, which won't help.
> 
> ...


LOL ... taking it too personal!!!


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## etsherman (Aug 2, 2011)

supers05 said:


> Found more examples.
> 
> We told you that IR guns are inaccurate, especially on condenser coils, and similar surfaces. You continued to use it. It's a long thread, so maybe I'm forgetting, but I think you mentioned getting A better ir gun, which won't help.
> 
> ...


supers05, the IR gun that I am using is sufficient for what I am doing. Granted, it may not be the exact tool a HVAC specialist would use and I understand that. Close readings within range is all that I'm after. I don't plan on redoing the a/c duct work, returns and vents on a system that is working and has worked over the past 33 years. We have had hot summers before here in Houston, this is nothing new. With electric costs constantly going up ... this year I just decided to look into reducing my kWh's consumption during those extremely hot periods. That's what generated the original question of whether shading the outside unit would make a difference since it sit in the western sun most of the day. That was quickly determined that it would not and I went with plan B ... adding misters. Every post and comment I made has always been focused on the outside temperature of and around the a/c unit ... not the inside air circulation. You and your comrades decided to attack, diagnose and come to a final definitive conclusion as to the performance of the air distribution inside the home over the internet for which I honestly feel is kind of a stretch even for a HVAC specialist.

I'm not trying to test and or compete with your knowledge in the HVAC industry. Things will be done differently where you are compared to where I live here in Texas. Building codes are different and HVAC installation methods will be different and I expect that. Your methodology and scientific research in the HVAC industry simply cannot be applied to all situations regardless of how well fine tuned and efficient you see it as.

Even here, 33 years ago the building codes were a lot different compared to today. However, one of the things I will do is replace those single pane windows with high-efficiency insulated low-E glass windows. That will make a big difference in summer and winter. Also, I will look into conditioning the attic space with spray foam insulation or some other method. Should be pretty easy to do and would be well worth it.


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## user_12345a (Nov 23, 2014)

You don't know what you're talking about.

Actually, the same methodology and understanding of theory can be applied to every situation.

Your IR thermometer is as inaccurate in your application for measuring air temp as in any other.

If there are poorly done ducts, they have the same effect in different areas.

Low airflow, high duct pressure as an example has the same effect on system capacity, efficiency in texas as it does in Ontario. 

So does having a unit overcharged with refrigerant.

"working fine" means cooling fine on the surface, it doesn't mean the equipment is running optimally or the distribution is correct. 

You can actually lose a lot of capacity to different problems, the problems can cover up each other. Your 5 ton unit may only be delivering 3 or 4 tons of capacity to the space, the 10 seer efficiency could be as low as 6 or 7 in reality.

Addressing route problems doesn't necessarily mean re-doing air ducts.

Long term, you won't get anywhere with what you're doing unless your goal is to ruin your unit to save under 10% on the utility bills. You can argue all you want.

Please read: http://www.vies.vi/docs/default-source/resources/seer-facts-bulletin.pdf?sfvrsn=2


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## supers05 (May 23, 2015)

etsherman said:


> supers05, the IR gun that I am using is sufficient for what I am doing. .....


Actually it isn't, unless you have a wired probe attached to it, and using that temp instead. IR guns do NOT measure air temp. They measure IR intensity, which the majority comes from the surface that you're pointing at. They do not work well on reflective surfaces, as they also reflect the IR energy from other surfaces. You might get close when pointing at a mat coloured grill, as long as you're angled so you can't see through the grill. 

As for the rest, they were suggestions. Some very decent things you should be checking if you really wanted to save energy. 

We only confirmed some of the potential issues as you replied, attempting to defend ductwork that you, yourself have no idea if it's actually optimal. You only have the word of the commissioning techs. They may have been mostly right, or may have not actually cared. Either way, again since this is a public DIY forum, expect suggestions and critiques on every post. 

The biggest reason why we keep pointing out your errors and measurement biasrs, is to help the unfortunate future readers that stumble upon this thread. They should know that misters not only have serious side effects, but also have marginal benefits with a properly working system. There are better ways to increase efficiency then waste water that is quite limited in many places. 

Instead of having a constructive conversation on how to improve your efficiency, you chose to get defensive and pretend that nothing could be wrong with your system, and your misters will save the planet. All while personally attacking those trying to actually help you, then accusing us of being too sensitive. At this point I'm convinced that you have no idea how these online communities actually work. 

Cheers!


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## etsherman (Aug 2, 2011)

user_12345a you said ... "You don't know what you're talking about."

There we go again with the insults from you and your comrades. The title of the thread itself is "Outside" ambient temp and is my point exactly. You and your friends decided to band together in the background and try to throw as much mumbo jumbo HVAC b/s against this thread simply because you are not an advocate of using misters. So the concept is let's all band together and defeat what he is posting regarding using misters in extremely high temperature settings. That's your opinion and decision but it's certainly not the bible for HVAC standards. There are some developments west of Texas where misters are standard and in some cases required!!!

What you and your comrades fail to accept is that the typical household a/c system is basically an air cooled system. That means at some point the the hotter the air is outside and the hotter the equipment is, those two factors can and will defeat the units purpose thus making it totally inefficient. A water cooled engine works better than a air cooled engine ... that's a fact!!

The misters simply work and I more than proved that by showing you and your comrades the kWh's dropped by 40% for the most part on those significantly hot days. Personally, I'm neither interested nor impressed by you and your comrades technical mumbo jumbo thrown at this thread to try and defeat those results!!! Numbers is what interest and impress me not B/S ... OK. 

No, I will not allow you and your buddies to sit on your "HAVC THRONE" and hijack this thread while completely disrespecting a home that was built 33 years ago by a very reputable, competent and experienced building corporation. That in itself speaks volumes about your character and that of your buddies!!!

Outside temps is what I am focused on!!!

Now, if I remove the solar screens as shown in the top photo the temp inside the house on hot days will significantly increase. It has nothing to do with the duct work, location of the return, the type of IR gun, etc. The single pane windows allows more sunlight and radiant heat to enter the home. Just by installing those solar screens years ago made a big difference in energy consumption. This is why I will eventually replace those windows with “Low-E” low emissivity windows. That's where my focus is ... not the darn duct work that is functioning properly and has been for the last 33 years. Those screens are not made of material that can be found at your local Big Box DIY stores. It is expensive and is also coated with some type of coating that emits low levels of radiant heat. One of the reasons I haven't replaced those windows yet because the screens work so well.

If you want to comment on the thread then please do ... just focus your comments on misters and shading ... that's what the thread is about.

Thanks,


----------



## user_12345a (Nov 23, 2014)

lol.

This is a thread that needs to be pinned at the top of this page with a disclaimer - what not to do.

You're focusing on the wrong things; the capacity and efficiency loss of a properly operating unit isn't very great at 100f compared to the normal 95.



> Numbers is what interest and impress me not B/S ... OK.


So get some accurate numbers.

Would need to measure airflow (https://www.fieldpiece.com/products/detail/sta2-in-duct-hot-wire-anemometer/anemometers/), compressorcurrent with a clamp ammeter, change in enthalpy using wetbulb thermometers.

The impact on capacity and efficiency misters have can be directly calculated at different outdoor temps.

Would need to make sure the unit is actually charged right using subcool/superheat - not just the usual pressures. Reason is to rule out a problem with your system that the misters are covering up.

An overcharged unit runs a very high head pressure and has liquid stacked in the condenser coil, leading to high amp draw and reduced capacity.

The misters could be covering this up.

Units can be overcharged by hack technicians to get normal suction pressure when the airflow and/or return air temp is too low.

You have no idea what's really going on with your system - this is just the truth, it's not an insult. Educate yourself more if you want to get a better handle.

oh BTW - one of the reasons why your electric bills are so high is because this house is one level; they need far more heating and cooling than two story homes of the same square footage.


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## etsherman (Aug 2, 2011)

"You have no idea what's really going on with your system - this is just the truth, it's not an insult. Educate yourself more if you want to get a better handle."

I do know this though .... The misters are working so efficiently that I moved the hold temp at the thermostat up 1 degree from 76° to 77° over the last couple of days. Now, I just walked into the kitchen and looked at my control panel. It shows a 98° outside temp at 6:22 pm today which was just a few minutes ago. The thermostat has been set to 77° all day and the misters are activated. My daughter is sitting on the couch in the family room with 14 ft ceilings and she is complaining that she is cold!!! The house is comfortable all throughout!!! No, I never claimed to be an a/c guru ... but I do know that!!!


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## kevinande (Aug 13, 2018)

Etsherman. Yes the misters will work. However everything comes at a cost. Spraying water on the condenser lowers the head pressure, lowering the flow through the fixed oriface, therefore less cooling. Efficiency can go up as compressor amps decrease. You will need to add refrigerant to get enough cooling. If your system uses a TXV this will probably be a non issue. Despite your feelings and IR thermometer you can not change the laws of physics. More detrimental to your system is the constant water on the condenser. They were not designed for that. At best some deposits on the coil fins at worst a real rust problem. I hope it works out for you, however in general not a good idea. The savings seem worth it now, however it will hardly seem worth it when you are forced to purchase a new system prematurely. Good luck.


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## etsherman (Aug 2, 2011)

kevinande said:


> Etsherman. Yes the misters will work. However everything comes at a cost. Spraying water on the condenser lowers the head pressure, lowering the flow through the fixed oriface, therefore less cooling. Efficiency can go up as compressor amps decrease. You will need to add refrigerant to get enough cooling. If your system uses a TXV this will probably be a non issue. Despite your feelings and IR thermometer you can not change the laws of physics. More detrimental to your system is the constant water on the condenser. They were not designed for that. At best some deposits on the coil fins at worst a real rust problem. I hope it works out for you, however in general not a good idea. The savings seem worth it now, however it will hardly seem worth it when you are forced to purchase a new system prematurely. Good luck.


Thanks ... system is 14 years old, been through several storms and other adverse weather events. I got 19 years out of my old Carrier unit. I am about due for a new unit in the near future so that's really not a concern for me right now. Of course I will keep an eye on the unit and the misters are only used on days when the temp is above 85°. It's really not a constant flow of water to be honest ... more like steam the way I have those mister turned down. Only one per side ... not much water ... I monitor it daily.

Thanks ...


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## etsherman (Aug 2, 2011)

"Etsherman. Yes the misters will work. However everything comes at a cost."

You are so right about that and is the reason I never said this was a perfect solution or it should be implemented globally. It simply works for my situation. My attic can get up to 130° to 140° on a good Houston day. A while back I talked with my roofing contractor that installed my new roof 2 years ago about the effect of spray foaming the the attic including the rafters and roof decking. He said there are different opinions out there but overall you should be OK. Other roofing contractors will tell you don't do it because you will essentially bake the shingles from the underside as the foam insulation will not allow the heat to pass through the shingles into the attic thus shortening their life. My contractor feels that's b/s simply because the shingles are already sitting on top of a 130° attic so lowering the temperature in there would only help not damage the shingles. Nothing in life is ever going to be 100% perfect ... you just have to decide what works best for you and stay on top of it. 

My objective was to simply lower the kWh's my outside condenser/compressor was using during extreme hot Houston days (85° to 101°) we have been experiencing and it doesn't appear to be letting up anytime soon. All I am saying is the misters did that.

Thanks


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## beenthere (Oct 11, 2008)

Yes you have.


But you still haven't posted the amount of water the misters are using per minute, hour or day.


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## etsherman (Aug 2, 2011)

beenthere said:


> Yes you have.
> 
> 
> But you still haven't posted the amount of water the misters are using per minute, hour or day.


LOL I will not because I don't need a technical lesson or formula on how to "correctly" measure water usage. I will simply compare the water bills from the previous month without the misters and the current billing cycle which will include the misters being activated. Based on what's coming out of the misters and the compressor not running as much to maintain the temperature inside the house ... I actually anticipate about a $6 increase in water usage.

Thanks ...


----------



## supers05 (May 23, 2015)

etsherman said:


> ... A water cooled engine works better than a air cooled engine ... that's a fact!!.....,


Unless you're talking about a boat or snowmobile, or similar, a water cooled engine is still cooled by air. Water is considered a refrigerant, and is simply used to transport heat to a convenient location. Just like your AC. It just has no need to be cooler then ambient temps, like humans. 



etsherman said:


> ...
> Now, if I remove the solar screens as shown in the top photo the temp inside the house on hot days will significantly increase. It has nothing to do with the duct work, location of the return, the type of IR gun, etc. ..,


Actually, if you're ductwork was designed right, and you had the right size unit, there should be minimal difference in temperature. The unit would just work a bit longer without the shades. Your electricity usage would change, but not the temp. With the shades, most people would close the room dampers a tad to prevent the larger swings. Again more proof that the ductwork isn't up to the industry standards. 

PS. We couldn't care about some random house, or it's builder. We still don't. We're talking about what you've posted, and that's it. The points above just clarifies that you don't know how these systems work, other then turning it on, and cool air comes out. It's not an insult, it's a fact, proven several times over. The vast majority of members here wouldn't have got defensive, but rather asked to be educated instead. It's just a bit amusing at this point to pick apart your posts. It's quite easy. Skim the past few hundred threads and you won't see this, you're just special. 

Cheers!


----------



## beenthere (Oct 11, 2008)

etsherman said:


> LOL I will not because I don't need a technical lesson or formula on how to "correctly" measure water usage.
> 
> 
> LOL, thats a bit of a cop out.
> ...



Is your area known for high or low water sewer rates.


----------



## digitalplumber (Jul 8, 2011)

beenthere said:


> Is your area known for high or low water sewer rates.




https://www.sugarlandtx.gov/322/Water-Wastewater-Rates


----------



## digitalplumber (Jul 8, 2011)

etsherman said:


> "You have no idea what's really going on with your system - this is just the truth, it's not an insult. Educate yourself more if you want to get a better handle."
> 
> I do know this though .... The misters are working so efficiently that I moved the hold temp at the thermostat up 1 degree from 76° to 77° over the last couple of days. Now, I just walked into the kitchen and looked at my control panel. It shows a 98° outside temp at 6:22 pm today which was just a few minutes ago. The thermostat has been set to 77° all day and the misters are activated. My daughter is sitting on the couch in the family room with 14 ft ceilings and she is complaining that she is cold!!! The house is comfortable all throughout!!! No, I never claimed to be an a/c guru ... but I do know that!!!




ET are you sure that stat temp on your alarm is coming from on outside sensor at your house, or the internet?


----------



## etsherman (Aug 2, 2011)

digitalplumber said:


> ET are you sure that stat temp on your alarm is coming from on outside sensor at your house, or the internet?


Outside sensor.

Thanks,


----------



## etsherman (Aug 2, 2011)

supers05 said:


> Unless you're talking about a boat or snowmobile, or similar, a water cooled engine is still cooled by air. Water is considered a refrigerant, and is simply used to transport heat to a convenient location. Just like your AC. It just has no need to be cooler then ambient temps, like humans.
> 
> 
> 
> ...


It's more amusing for me to see you display and confirm how insecure you are. You have some modest experience/knowledge at most in the HVAC industry and you feel this is your only niche that sets you apart from the rest of the world. You can't go at it alone ... you have to have the "we" mindset as in stack the deck to ensure the outcome ... 3 to 1, 4 to 1, etc. That shows weakness in your ability to stand on YOUR own. The thread has been viewed by hundreds of other HVAC techs with probably more knowledge and experience compared to you and they simply read and move on. They are smart enough to know that any individual that has made the decision to try misters on their a/c unit is going to do that!! They don't have to prove them wrong, they know there are pros and cons to the concept and if someone is willing to accept the cons ... then so be it ... no big deal. They don't have to save the world from a/c misters!!!


----------



## supers05 (May 23, 2015)

etsherman said:


> ... The thread has been viewed by hundreds of other HVAC techs with probably more knowledge and experience ...


That's very likely. HVAC is my weaker skillset. Improving by the day. I'm definitely not concerned with it. I already know that I'm already top league locally, and make my living. I manage several techs under me, the forum is a hobby to me. Like I said earlier, I honestly responded purely to help you. Your the one that changed that.

PS. It takes 5 years of schooling and on the job training, and a final written exam to be certified here. We are pushing to add a collage program as a requirement now. Most jurisdictions have minor training requirements. I don't know about your area, but I think it's just a written test. 

Cheers!


----------



## etsherman (Aug 2, 2011)

As the saying goes ... a picture is worth a thousand words. A few post back the HVAC Guru's posting to this thread were going round and round about the "Correct/Proper" placement of the a/c return air vent(s). As clearly pointed out we do things differently down here and it's not necessarily wrong. This house is on the market just down the street from where I live. It is 4,900 sq. ft., 2 story, probably zoned a/c and was built in 1998 ... which was 13 years after my home was constructed. Now, notice where the return a/c vents are located. This is the most common and most acceptable method that I've seen here in Texas although there are some installs where the return is located in the ceiling. I really don't see it as a right or wrong as I'm sure the the building codes would have been changed if that was really a significant issue!!! IJS


----------



## supers05 (May 23, 2015)

That's because the people making policy, simple don't care how much electricity you waste. If it's your preference to trade lower efficiency for cosmetics and ease of access, that's a preference. Doesn't make it right. 

Those are decent sized houses. You'd think that you could spare a few square feet for a utility room where you could easily reach it. Not only would it be in conditioned space, but the filter could also be there, meaning you could have many return air grills spread throughout the house. The builder cheaped out. It's typical of the building industry across North America 

Cheers!


----------



## roughneck (Nov 28, 2014)

etsherman said:


> As the saying goes ... a picture is worth a thousand words. A few post back the HVAC Guru's posting to this thread were going round and round about the "Correct/Proper" placement of the a/c return air vent(s). As clearly pointed out we do things differently down here and it's not necessarily wrong. This house is on the market just down the street from where I live. It is 4,900 sq. ft., 2 story, probably zoned a/c and was built in 1998 ... which was 13 years after my home was constructed. Now, notice where the return a/c vents are located. This is the most common and most acceptable method that I've seen here in Texas although there are some installs where the return is located in the ceiling. I really don't see it as a right or wrong as I'm sure the the building codes would have been changed if that was really a significant issue!!! IJS


There’s nothing wrong with a central return. It just means the builder took the cheap way out when laying out the system. 
Ducted return can be much more comfortable and quieter for the occupants of the house. And much more efficient.


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## user_12345a (Nov 23, 2014)

The single low level return is not good for cooling -> the hottest air stays at the higher levels of the house, supply air sinks down.

The return air temp falls well below the average air temp of the house with this setup, so the indoor coil doesn't get a very good heat load causing capacity loss.

The load on the indoor coil impacts capacity more so than outdoor temperature.

Low airflow due to badly done ducts can further compound the problem.

The delivered capacity, between all the install problems can fall way below rated as stated many times before. 

Sounds like texas is really crappy when it comes to building codes and construction practices. I'm betting down there, the builders are still putting up houses with 2x4s plus only putting like R20 in the attic.

Probably, pot lights are super common down there as they are elsewhere and are installed in second floor ceilings, poorly causing excessive leakage to the attic. As if all the penetrations for the ducts (which don't belong in an unconditioned attic) aren't enough.


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## digitalplumber (Jul 8, 2011)

user_12345a said:


> The single low level return is not good for cooling -> the hottest air stays at the higher levels of the house, supply air sinks down.
> 
> The return air temp falls well below the average air temp of the house with this setup, so the indoor coil doesn't get a very good heat load causing capacity loss.
> 
> ...




I hear what you are saying, my downstairs has 2 returns: one in master bedroom ceiling and the second in the ceiling near the open area family room with 8 foot ceiling. Unfortunately, while I agree with your pulling the ceiling hot air during cooling, it kills me during winter. Ideally, one up and one down would be great for me. 


Now before you tell me I am wrong, we tested this theory by connecting a 10 foot long 20 inch return duct to the ceiling return in order to pull low cool air. It made the downstairs more comfortable during the winter.


----------



## windowguy (Jan 27, 2009)

user_12345a said:


> Different units can have different exhaust air temps. So many things that influence that - different condenser cfm vs capacity which can vary even for the same model line.
> 
> Units of different efficiency ratings -> the higher the efficiency, the less energy is consumed by compressor which gets absorbed by refrigerant and ejected in form of heat.
> 
> ...


how can i learn more about different CFM units? like literarlly one system blows softer than another? and i'm not talking about those tiny high velocity duct systems. I have one unit that barely makes any sound at the supply registers and the one on the next floor sounds like jet turbines. I just presumed it was the labrynth of twists and turns the vents went through that slowed down the "force" of the air.

i'm very interested in knowing how to tell if a unit purposely blows "softer" than another one. and i mean like so soft you are hard pressed to know the system is even on.

Edit: and i mean two different systems. Not one system, and one duct is loud and the other is quiet. I mean one unit where all 5 of the ducts are whisper quiet.


----------



## digitalplumber (Jul 8, 2011)

windowguy said:


> how can i learn more about different CFM units? like literarlly one system blows softer than another? and i'm not talking about those tiny high velocity duct systems. I have one unit that barely makes any sound at the supply registers and the one on the next floor sounds like jet turbines. I just presumed it was the labrynth of twists and turns the vents went through that slowed down the "force" of the air.
> 
> i'm very interested in knowing how to tell if a unit purposely blows "softer" than another one. and i mean like so soft you are hard pressed to know the system is even on.
> 
> Edit: and i mean two different systems. Not one system, and one duct is loud and the other is quiet. I mean one unit where all 5 of the ducts are whisper quiet.




You probably should start your own post equipment of system. Could be normal if your units sizes are different. But based on what you describe, jet sound, I am sure pros my say its a sign of oversized blower.


----------



## supers05 (May 23, 2015)

digitalplumber said:


> I hear what you are saying, my downstairs has 2 returns: one in master bedroom ceiling and the second in the ceiling near the open area family room with 8 foot ceiling. Unfortunately, while I agree with your pulling the ceiling hot air during cooling, it kills me during winter. Ideally, one up and one down would be great for me.
> 
> 
> Now before you tell me I am wrong, we tested this theory by connecting a 10 foot long 20 inch return duct to the ceiling return in order to pull low cool air. It made the downstairs more comfortable during the winter.


You're not wrong. This is why we said that it depends on the needs of the house, many posts back. Ideally, you'd have an equal number of high and low returns, in the same locations, all with dampers. You use the high in the summer and the low in the winter. I've added them to several houses with only 1 or 2 central returns, and it makes a world of difference.

Cheers!


----------



## digitalplumber (Jul 8, 2011)

supers05 said:


> You're not wrong. This is why we said that it depends on the needs of the house, many posts back. Ideally, you'd have an equal number if high and low returns, in the same locations all with dampers. You use the high in the summer and the low in the winter. I've added them to several houses with only 1 or 2 central returns, and it makes a world of difference.
> 
> Cheers!




Yep that would be an ideal scenario!


----------



## user_12345a (Nov 23, 2014)

With ceiling registers, it's really important to have low returns for heating to stop the stratification -> remove air near the floor and the supply can take it's place rather than rise up.

With floor registers, it's not crucial.


----------



## supers05 (May 23, 2015)

user_12345a said:


> With ceiling registers, it's really important to have low returns for heating to stop the stratification -> remove air near the floor and the supply can take it's place rather than rise up.
> 
> With floor registers, it's not crucial.


You still have issues with floor registers in the summer, with the same stratification. My previous house has low wall registers (pre WW2 house) and the stratification was horrific. Your feet were 65*f, your mid-body was 73*, and your head was 80*. Converting one of the 2 central returns to a mid level return helped significantly. It wasn't perfect, as I wasn't allowed to do much work there. (Rental) 

Cheers!


----------



## beenthere (Oct 11, 2008)

etsherman said:


> As the saying goes ... a picture is worth a thousand words. A few post back the HVAC Guru's posting to this thread were going round and round about the "Correct/Proper" placement of the a/c return air vent(s). As clearly pointed out we do things differently down here and it's not necessarily wrong. This house is on the market just down the street from where I live. It is 4,900 sq. ft., 2 story, probably zoned a/c and was built in 1998 ... which was 13 years after my home was constructed. Now, notice where the return a/c vents are located. This is the most common and most acceptable method that I've seen here in Texas although there are some installs where the return is located in the ceiling. I really don't see it as a right or wrong as I'm sure the the building codes would have been changed if that was really a significant issue!!! IJS





That home has 2 systems, or it also has a return up on the second floor. Other wise the second floor would be an oven compared to the first floor.


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## etsherman (Aug 2, 2011)

bahahahahahahahaha ... To all the skeptics and HVAC Guru's that are totally against using misters on your a/c unit during extreme hot weather conditions with the primary concerns being additional water usage along with mineral buildup on the unit!!!

This is the way an Accountant would measure water usage and no I do not have a degree in physics nor am I a HVAC specialist that I have been reminded of in just about every "pick apart" response on this thread.

I compared my July billing cycle water usage to my August billing cycle usage which includes approx. 2 weeks with the misters running. Also, the 7 zone sprinkler system was increased from 3 minutes each cycle once a week to 3 minutes per cycle every other day. In addition, the pets are drinking more water from the outside pet water fountain because of the extreme heat. My current water bill increased by a whopping $4.71, not even the cost of a Happy Meal at McDonalds ... heeheeheeheee!! Now, I got the popcorn, hot dogs and chili waiting for the "pick apart" post on this one. This should be interesting!!!

Hard to believe that as experienced and knowledgeable as some claim to be that you would debate a simple concept as adding a mist of water to an outside a/c unit in 100° temperatures will make the unit work more efficiently and it has absolutely nothing to do with the duct work or location of the a/c return vents!!!

In a few years, global warming is going to send some of those 100 degree days up and over the Canadian border and I can guarantee you that beenthere, supers05 and user_12345a will be the first ones out there adding misters to their units!!! I will put some money on that!!!

The finely atomized mist of water is not going to hurt that a/c unit simply because after much prolonged use ... should their be a mineral buildup it can be cleaned and removed!!! Now What????


----------



## digitalplumber (Jul 8, 2011)

etsherman said:


> bahahahahahahahaha ... To all the skeptics and HVAC Guru's that are totally against using misters on your a/c unit during extreme hot weather conditions with the primary concerns being additional water usage along with mineral buildup on the unit!!!
> 
> This is the way an Accountant would measure water usage and no I do not have a degree in physics nor am I a HVAC specialist that I have been reminded of in just about every "pick apart" response on this thread.
> 
> ...




ET, while I am sure I am included in your "punch" some how and you appear to be a very smart person, explain to me, why this is not an industry standard?


----------



## supers05 (May 23, 2015)

etsherman said:


> ...with the primary concerns being additional water usage along with mineral buildup on the unit!!!


You haven't even fully understood what we said. 

PS. Beenthere isn't in Canada. I'd never add misters to my AC unless i needed it to last a few days so I could order a new one and install it. There's other ways to increase efficiency. Methods that won't kill your coil. 

On the other side, you haven't said now much more water you've actually used. You already said that your have ridiculously cheap electricity, so without usage, future readers will find it useless. IE. Water prices in California are not the cheapest 

Cheers!


----------



## beenthere (Oct 11, 2008)

etsherman said:


> bahahahahahahahaha ... To all the skeptics and HVAC Guru's that are totally against using misters on your a/c unit during extreme hot weather conditions with the primary concerns being additional water usage along with mineral buildup on the unit!!!
> 
> This is the way an Accountant would measure water usage and no I do not have a degree in physics nor am I a HVAC specialist that I have been reminded of in just about every "pick apart" response on this thread.
> 
> ...



Well, after you have had your misters system running for 2 years, get back to us how easy it is to get all the mineral build up off of the condenser.


----------



## etsherman (Aug 2, 2011)

digitalplumber said:


> ET, while I am sure I am included in your "punch" some how and you appear to be a very smart person, explain to me, why this is not an industry standard?


LOL ... not really ...

Exact same reason building codes will not force builders to put a permanent roof on homes down here. It keeps the shingle manufactures and roofing industry in business. Simple logic ... heat destroys anything and the cooler the machine operates then the longer it will last. Therefore, the industry will not make as much money!!! They want it to sit and operate in the 100° temperatures from the day you purchase it. They know the clock is ticking in their favor. Most people don't think about that but it's just hard core facts.

Friends visited from England and they are still confused as to why we put paper shingles on the most exposed area of the house!!! Think about that for a minute!!! 2 years ago, my neighbor had changed their roof 12 months before I did. Shortly there after we took a bad hail strike ... no wind damage but large hail. My roof had to be replaced as well as theirs ... 18K each!!!. Manufactures simply want the repeating customer ... built in obsolescence!!! A permanent roof would have taken that hail strike with ease.


----------



## etsherman (Aug 2, 2011)

supers05 said:


> You haven't even fully understood what we said.
> 
> PS. Beenthere isn't in Canada. I'd never add misters to my AC unless i needed it to last a few days so I could order a new one and install it. There's other ways to increase efficiency. Methods that won't kill your coil.
> 
> ...


Yeap ... and that's why I said after considering all that's involved, if misters can work for you then it can make a difference in your monthly power usage by making you a/c unit work more efficiently.


----------



## roughneck (Nov 28, 2014)

etsherman said:


> LOL ... not really ...
> 
> Exact same reason building codes will not force builders to put a permanent roof on homes down here. It keeps the shingle manufactures and roofing industry in business. Simple logic ... heat destroys anything and the cooler the machine operates then the longer it will last. Therefore, the industry will not make as much money!!! They want it to sit and operate in the 100° temperatures from the day you purchase it. They know the clock is ticking in their favor. Most people don't think about that but it's just hard core facts.
> 
> Friends visited from England and they are still confused as to why we put paper shingles on the most exposed area of the house!!! Think about that for a minute!!! 2 years ago, my neighbor had changed their roof 12 months before I did. Shortly there after we took a bad hail strike ... no wind damage but large hail. My roof had to be replaced as well as theirs ... 18K each!!!. Manufactures simply want the repeating customer ... built in obsolescence!!! A permanent roof would have taken that hail strike with ease.


Mineral and calcium deposits will kill your unit off much quicker then the heat will. So the local installers will be happy about that I suppose.


----------



## digitalplumber (Jul 8, 2011)

etsherman said:


> LOL ... not really ...
> 
> Exact same reason building codes will not force builders to put a permanent roof on homes down here. It keeps the shingle manufactures and roofing industry in business. Simple logic ... heat destroys anything and the cooler the machine operates then the longer it will last. Therefore, the industry will not make as much money!!! They want it to sit and operate in the 100° temperatures from the day you purchase it. They know the clock is ticking in their favor. Most people don't think about that but it's just hard core facts.
> 
> Friends visited from England and they are still confused as to why we put paper shingles on the most exposed area of the house!!! Think about that for a minute!!! 2 years ago, my neighbor had changed their roof 12 months before I did. Shortly there after we took a bad hail strike ... no wind damage but large hail. My roof had to be replaced as well as theirs ... 18K each!!!. Manufactures simply want the repeating customer ... built in obsolescence!!! A permanent roof would have taken that hail strike with ease.




So based on your roof theory, your HOA is involved in the "permanent roof" scam also, right?


----------



## etsherman (Aug 2, 2011)

"In an earlier post, you said your sprinkler system was on a separate line that isn't metered. So that adds nothing to your water bill. But it does help to keep the ground cooler and the A/C to work a little easier".

I remember the question but perhaps you misunderstood my response. That would be impossible to do ... each home has only one meter. I said my sprinkler system main feed line comes off of the main water line going into the house after the meter.

"You installed the mister system on the 30th of July. What date was your water metering reading/billing date. Without that, as far as we know, your new water bill may only include 6 days of the misters".

The August bill has approx 2 weeks with the misters running!!! I stated that in the post.

Thanks


----------



## etsherman (Aug 2, 2011)

digitalplumber said:


> So based on your roof theory, your HOA is involved in the "permanent roof" scam also, right?


Haven't heard of the "permanent roof" scam ... seriously. What are the details about that???

Thanks


----------



## digitalplumber (Jul 8, 2011)

etsherman said:


> Haven't heard of the "permanent roof" scam ... seriously. What are the details about that???
> 
> Thanks


You spoke of a "permanent roof" and not able to install. Personally, I have never heard of a "permanent" roof so I assumed you meant metal and being in the "high dollar" neighborhood you are in, again, I assumed your HOA did not allow, otherwise being the smart man you are, you would install!


----------



## supers05 (May 23, 2015)

etsherman said:


> Yeap ... and that's why I said after considering all that's involved, if misters can work for you then it can make a difference in your monthly power usage by making you a/c unit work more efficiently.


I don't think that it's possible that you've considered everything, as you still don't understand what I've said. 

I'm used to it, as many people turn to insults after they glaze over and start to feel inferior. 

Cheers!


----------



## etsherman (Aug 2, 2011)

digitalplumber said:


> You spoke of a "permanent roof" and not able to install. Personally, I have never heard of a "permanent" roof so I assumed you meant metal and being in the "high dollar" neighborhood you are in, again, I assumed your HOA did not allow, otherwise being the smart man you are, you would install!


per·ma·nent
adjective
1. lasting or intended to last or remain unchanged indefinitely.

When I compared options while replacing the roof after the hail strike contractors who installed tile, slate and metal roofs referred to them as permanent roofs as in they are intended to last for a long time compared to asphalt shingles. My HOA would have approved a metal roof ... I just did not want to fork over $40k for it compared to $18k. Big difference. 

My neighborhood is not at all considered "high dollar" ... Retail market value of my home is right around $325k with the highest in my subdivision somewhere around $385k. According to some Canadian posters ... that's all of a "Ghetto" in their neck of the woods!!! My neighborhood borders other more higher end subdivisions.


----------



## supers05 (May 23, 2015)

etsherman said:


> LOL ... not really ...
> 
> Exact same reason building codes will not force builders to put a permanent roof on homes down here. It keeps the shingle manufactures and roofing industry in business. Simple logic ... heat destroys anything and the cooler the machine operates then the longer it will last. Therefore, the industry will not make as much money!!! They want it to sit and operate in the 100° temperatures from the day you purchase it. They know the clock is ticking in their favor. Most people don't think about that but it's just hard core facts.
> 
> Friends visited from England and they are still confused as to why we put paper shingles on the most exposed area of the house!!! Think about that for a minute!!! 2 years ago, my neighbor had changed their roof 12 months before I did. Shortly there after we took a bad hail strike ... no wind damage but large hail. My roof had to be replaced as well as theirs ... 18K each!!!. Manufactures simply want the repeating customer ... built in obsolescence!!! A permanent roof would have taken that hail strike with ease.


I have no idea what building codes you're referring to, but there is plenty of roofing products that'll stand-up to the heat and even very large hail. 

Cheers!


----------



## etsherman (Aug 2, 2011)

digitalplumber question:

How much does your electric provider charge for the Centerpoint TDU Delivery Charge??

I'm with TXU and the kWh rates are not bad but I get nailed with the Deliver Charge from Centerpoint because they own the lines, meters, etc. That delivery charge is tied to the kWh's used hence the need to lower the usage.

This was my August 2018 Bill!!!

Thanks,


----------



## digitalplumber (Jul 8, 2011)

etsherman said:


> digitalplumber question:
> 
> How much does your electric provider charge for the Centerpoint TDU Delivery Charge??
> 
> ...


Don't know! See attached for bill.


----------



## etsherman (Aug 2, 2011)

digitalplumber said:


> Don't know! See attached for bill.


You don't have the Centerpoint TDU Delivery Charge!!!

1,500 kWh's for the month is pretty darn good!!!

Thanks,


----------



## beenthere (Oct 11, 2008)

etsherman said:


> "In an earlier post, you said your sprinkler system was on a separate line that isn't metered. So that adds nothing to your water bill. But it does help to keep the ground cooler and the A/C to work a little easier".
> 
> I remember the question but perhaps you misunderstood my response. That would be impossible to do ... each home has only one meter. I said my sprinkler system main feed line comes off of the main water line going into the house after the meter.
> 
> ...



Yes, you stated that. But you didn't post the date on the invoice like you should have. You also stated that your air distribution is perfect, and we know it isn't.So as far as we know, it may only be 6 days of water use.


----------



## etsherman (Aug 2, 2011)

beenthere said:


> Yes, you stated that. But you didn't post the date on the invoice like you should have. You also stated that your air distribution is perfect, and we know it isn't.So as far as we know, it may only be 6 days of water use.


The numbers that I posted are valid and accurate ... if they do not meet your certifications, then oh well, nothing else I can do.

I will compare the Sept. 2018 billing cycle on 09/10/2018 that will include a full 30+ days of the misters running to the July 2018 billing cycle that is a full 30+ days before the misters were activated. August billing cycles has 2 weeks of each!!!

Thanks,


----------



## supers05 (May 23, 2015)

You kept asking why don't they make versions that work with water. Well they do.... We mentioned it before, but I took a few pictures. 

Water is sprayed across the top and dribbles down. Air it pushed up. This is a small guy. On a day like today, (70%RH at midday) they aren't doing a whole lot better then an air cooled version. (In fact they are struggling as the air cooled version is 2x bigger.) 









This is what they have to do to keep the water from damaging the metals 









Cheers!


----------



## etsherman (Aug 2, 2011)

For all the HVAC Guru's that keep posting comments regarding duct work, air flow and distribution on this thread:

As said before, the home was built 33 years ago by one of the top home builders in Texas and is very respected in that industry. Any practical individual would simply make the assumption first that a builder of that caliber would not take short cuts on their projects and would have access to the most advance HVAC methods and efficiency options for the geographical region they are building in. Evidence of that is, after 33 years, several major catastrophic events ... it is still performing like the day it was built in 1985. That in itself speaks volume about the builder. The HVAC system in this home was designed and installed by professionals not some off the street contractor. The duct system includes a series of 4 in., 6 in. and 8 in. ducts all with baffles and matching vents that are also adjustable. Each time the HVAC system is serviced ... the air flow throughout the home is tested and adjusted if needed ... no refrigerant has ever been added to the unit in 14 years. The air flow going into each room has been balanced accordingly. 

If it's really that big of a difference ... then why haven't one of you published an article or white paper on the "Correct/Proper" way HVAC systems should be installed in the Southern Region of the US??? Show me some of your documented work displaying the vast inefficiency in the way a HVAC system like I have compared to your installed HVAC system!!! I would really like to see that ... not the theory ... the actual results!!!


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## digitalplumber (Jul 8, 2011)

etsherman said:


> For all the HVAC Guru's that keep posting comments regarding duct work, air flow and distribution on this thread:
> 
> As said before, the home was built 33 years ago by one of the top home builders in Texas and is very respected in that industry. Any practical individual would simply make the assumption first that a builder of that caliber would not take short cuts on their projects and would have access to the most advance HVAC methods and efficiency options for the geographical region they are building in. Evidence of that is, after 33 years, several major catastrophic events ... it is still performing like the day it was built in 1985. That in itself speaks volume about the builder. The HVAC system in this home was designed and installed by professionals not some off the street contractor. The duct system includes a series of 4 in., 6 in. and 8 in. ducts all with baffles and matching vents that are also adjustable. Each time the HVAC system is serviced ... the air flow throughout the home is tested and adjusted if needed ... no refrigerant has ever been added to the unit in 14 years. The air flow going into each room has been balanced accordingly.
> 
> If it's really that big of a difference ... then why haven't one of you published an article or white paper on the "Correct/Proper" way HVAC systems should be installed in the Southern Region of the US??? Show me some of your documented work displaying the vast inefficiency in the way a HVAC system like I have compared to your installed HVAC system!!! I would really like to see that ... not the theory ... the actual results!!!



Hope its not a Newmark Home!


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## etsherman (Aug 2, 2011)

supers05 said:


> You kept asking why don't they make versions that work with water. Well they do.... We mentioned it before, but I took a few pictures.
> 
> Water is sprayed across the top and dribbles down. Air it pushed up. This is a small guy. On a day like today, (70%RH at midday) they aren't doing a whole lot better then an air cooled version. (In fact they are struggling as the air cooled version is 2x bigger.)
> 
> ...


Yep, with 70%RH ... misting is not going to be very effective. Keep in mind that I am targeting extreme hot dry days here in Houston. They are forecasting this to continue through the end of September!!!

You just have to make a setup like this for us hot folks down here in Texas ... LOL!

Thanks,


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## etsherman (Aug 2, 2011)

digitalplumber said:


> Hope its not a Newmark Home!


LOL no ... Perry Homes. I've heard some complaints about Newmark!!!


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## etsherman (Aug 2, 2011)

Local company in Houston taking a/c misters to a higher level. More sensors, only operates when the outside temp reaches a certain level, wind turbine charges the battery!! 

It's only going to get better and cheaper!!!

https://www.kickstarter.com/projects/19381/mistbox-energy-saving-device-proven-to-cut-ac-bill


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## user_12345a (Nov 23, 2014)

You can claim the builder is perfect so your duct system is too - but hvac is probably one of the least understood fields by generalists and good duct systems don't sell houses.

Who built the house means nothing as as previously stated several times, the results as well as pictures you posted indicate the duct isn't the greatest. 

I'm not sure why this thread keeps on going on. Enjoy your misters.


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## beenthere (Oct 11, 2008)

etsherman said:


> For all the HVAC Guru's that keep posting comments regarding duct work, air flow and distribution on this thread:
> 
> As said before, the home was built 33 years ago by one of the top home builders in Texas and is very respected in that industry. Any practical individual would simply make the assumption first that a builder of that caliber would not take short cuts on their projects
> 
> ...



As I said, your 2 rooms at the return have too much air going to them. The doors wouldn't blow closed if they didn't.


I confess, I did think higher of your distribution system, until you posted the pics of the supply registers. In a predominately cooling area like yours. With high supplies, and a low return. Supply registers that aid the air staying high against the ceiling work better than ones that throw the air downward. Unless the position of the registers would allow air stagnation in the room its in.


With the supplies in the ceiling and the return down low at the floor, the supply registers don't need to force the warm/hot air downward.


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## user_12345a (Nov 23, 2014)

supers05 said:


> This is what they have to do to keep the water from damaging the metals


They use corrosion inhibitor chemicals and keep the mineral content under as well, right.

I know on steam boilers they have to do blow-down to maintain a certain maximum cycles of concentration and must do something similar for water cooled systems.


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## beenthere (Oct 11, 2008)

PS: How often do you dust around your registers.


Oh, that mist bot thing has been out for a while now, its not anything new either.


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## etsherman (Aug 2, 2011)

user_12345a said:


> They use corrosion inhibitor chemicals and keep the mineral content under as well, right.
> 
> I know on steam boilers they have to do blow-down to maintain a certain maximum cycles of concentration and must do something similar for water cooled systems.


That's why I mentioned in the onset that I have a whole house water filtration system that pretty much delivers bottled quality water at every faucet in the house except one exterior spigot. This filtration unit greatly reduces the mineral content in the water. The faucet the misters are connected to is included in this filtration process. The ice in the ice maker is clear just like if you froze a bottle of store bought water!!! Mineral build up is not a real concern for me right now ... although I will keep a close eye on the coils/fins.


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## user_12345a (Nov 23, 2014)

What kind of filtration unit is it?

The water softener type does not reduce mineral content, it just replaces them with minerals that don't form hard water deposits.

The reverse osmosis type takes everything out - biological hazards, minerals, chlorine, fluoride, pesticides.

Distillers take the minerals out.


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## supers05 (May 23, 2015)

user_12345a said:


> They use corrosion inhibitor chemicals and keep the mineral content under as well, right.
> 
> I know on steam boilers they have to do blow-down to maintain a certain maximum cycles of concentration and must do something similar for water cooled systems.


They use an auto purge to lower concetrations. They have corrosion inhibitors, microbial growth inhibitors, Scale / Deposition Control, and that control continuously monitors conductivity. (Indicates ion content.)

It's actually rather expensive and air coolers are regaining popularity at that size. (The larger size, and price is the biggest reason why they aren't use normally.) 

Cheers!


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## user_12345a (Nov 23, 2014)

yah water treatment for these things is a trade in itself.


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## supers05 (May 23, 2015)

user_12345a said:


> yah water treatment for these things is a trade in itself.


Yup. It's all sub-contracted out. That's all they do. 

Cheers!


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## etsherman (Aug 2, 2011)

user_12345a said:


> What kind of filtration unit is it?
> 
> The water softener type does not reduce mineral content, it just replaces them with minerals that don't form hard water deposits.
> 
> ...


It's not a softener ... it is a whole house filtration system ... delivers bottled quality water and removes a significant portion of the chemicals. No system can remove all of them. This one makes a big difference..

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> It's not a softener ... it is a whole house filtration system ... delivers bottled quality water and removes a significant portion of the chemicals. No system can remove all of them. This one makes a big difference..
> 
> Thanks,


I'm unfamiliar with your municipal water, but ours is actually cleaner then bottled water. We have soft water, but a few places have harder water. Very strict testing rules here in the big cities. 

Anyways, your electric and water rates seem very cheap. I know nothing about your state's utility management but it sounds heavily subsidized. 

Cheers!


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## u3b3rg33k (Jul 17, 2018)

bottled water quality is unregulated, so that statement doesn't mean anything. if it was a whole house RO system, that would at least tell us what it does.


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## supers05 (May 23, 2015)

u3b3rg33k said:


> bottled water quality is unregulated, so that statement doesn't mean anything. if it was a whole house RO system, that would at least tell us what it does.


It's regulated as a food here. Completely different then municipal water. There could be just about anything in bottled water.

Cheers!


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## user_12345a (Nov 23, 2014)

etsherman said:


> It's not a softener ... it is a whole house filtration system ... delivers bottled quality water and removes a significant portion of the chemicals. No system can remove all of them. This one makes a big difference..
> 
> Thanks,


This doesn't tell me what type it is, there are different types of filtration system. What it removes depends on type and if applicable, the filter medium.

For example you can buy a brita filter at a big box store with a carbon filter which only removes chlorine and other chemicals that make the taste bad.

Bottled water sucks, btw. The tap water I get is better, i just put it in the fridge and let the chlorine evaporate.


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## etsherman (Aug 2, 2011)

user_12345a said:


> This doesn't tell me what type it is, there are different types of filtration system. What it removes depends on type and if applicable, the filter medium.
> 
> For example you can buy a brita filter at a big box store with a carbon filter which only removes chlorine and other chemicals that make the taste bad.
> 
> Bottled water sucks, btw. The tap water I get is better, i just put it in the fridge and let the chlorine evaporate.


When I get a chance, I will dig through my file cabinet and find the manual for the system. It was put in about 4 years ago because I was looking for a solution to filter out the water we get here ... not bad but they increased the chlorine and other chemicals as the district started purchasing more surface water hence the RWA (Regional Water Authority) fee on my water bill. The items targeted were taste (chlorine), other minerals and sediments. I noticed the reduction in calcium deposits on the bathroom shower doors!!!


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## etsherman (Aug 2, 2011)

supers05 said:


> I'm unfamiliar with your municipal water, but ours is actually cleaner then bottled water. We have soft water, but a few places have harder water. Very strict testing rules here in the big cities.
> 
> Anyways, your electric and water rates seem very cheap. I know nothing about your state's utility management but it sounds heavily subsidized.
> 
> Cheers!


Our district started purchasing more surface water thus the increase in chlorine and other chemicals to the water. It's not bad but I would not consider it bottle quality either.

Thanks,


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## etsherman (Aug 2, 2011)

While at my local hardware store today, I had a chance to pick up the correct thermometer to measure air temps inside the house ... here are the results. I tested these as soon as the unit came on. The doors to the cool interior rooms next to the a/c return are fully opened.

A/C Condenser/Compressor Misters Running: Yes
Outside Temp: 105°
Thermostat Hold: 77°
Inside Temp: 78°
A/C Return Temp: 77.9°
Farthest Vent Temp: 62.1°
Closest Vent Temp: 56.7°

At 77° the 2,400 sq. ft. interior air conditioned space is fully comfortable in all rooms and the outside compressor can reach the thermostat setting without having to constantly run!!!

Thanks,


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## beenthere (Oct 11, 2008)

Generally, operating checks are not done until the unit has ran for at least 15 minutes.


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## etsherman (Aug 2, 2011)

beenthere said:


> Generally, operating checks are not done until the unit has ran for at least 15 minutes.


Yep, I wanted to see if that return air was much cooler than the room temp displayed on the thermostat. The unit did run for a couple minutes before I started testing however it was not 15 minutes ... more like 5 minutes.

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> While at my local hardware store today, I had a chance to pick up the correct thermometer to measure air temps inside the house ... here are the results. I tested these as soon as the unit came on. The doors to the cool interior rooms next to the a/c return are fully opened.
> 
> A/C Condenser/Compressor Misters Running: Yes
> Outside Temp: 105°
> ...


deltaT of 21.2*F. (Which includes short duct losses.) Your house would have to be exceptionally dry for that to be remotely normal. Your airflow is too low compared to your capacity. It's lowering your efficiency. 

Cheers!


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## user_12345a (Nov 23, 2014)

The temps need to be taken at inlet of furnace and outlet of the indoor coil.

Whether the delta-t is normal or not depends on the humidity.

I think 18ish drop is pretty normal for 50% humidity.

Can wrap thin moist material around the end of the thermometer and get wetbulb temp, determine humidity in return and what the drop should be.


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## etsherman (Aug 2, 2011)

supers05 said:


> deltaT of 21.2*F. (Which includes short duct losses.) Your house would have to be exceptionally dry for that to be remotely normal. Your airflow is too low compared to your capacity. It's lowering your efficiency.
> 
> Cheers!


Those are the numbers supers05 ... Closest station to my residence shows the humidity was at 42% when those readings were taken. 

House is very comfortable, a/c cooling like a champ and not constantly running even during peak temps. My outdoor sensor was showing 105° and it is located in the shade under the patio!!! 

Thanks,


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## etsherman (Aug 2, 2011)

user_12345a said:


> The temps need to be taken at inlet of furnace and outlet of the indoor coil.
> 
> Whether the delta-t is normal or not depends on the humidity.
> 
> ...


I'm not going to do that user_12345a ... The temps readings that I posted fully satisfied my objective. I don't have to get that precise in what I am doing, OK.

Thanks for the info anyway.


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## supers05 (May 23, 2015)

etsherman said:


> Those are the numbers supers05 ... Closest station to my residence shows the humidity was at 42% when those readings were taken.
> 
> House is very comfortable, a/c cooling like a champ and not constantly running even during peak temps. My outdoor sensor was showing 105° and it is located in the shade under the patio!!!
> 
> Thanks,


I never said it wasn't working. I said that you will have lower efficiency. Those are two different things. 

42%rh isn't that low. It's on the low side is average. Typically really comfortable. It does help confirm that your airflow is still low compared to the capacity. (Note that i didn't say compared to your house requirements. That is a different metric.) 

Cheers!


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## supers05 (May 23, 2015)

etsherman said:


> I'm not going to do that user_12345a ... The temps readings that I posted fully satisfied my objective. I don't have to get that precise in what I am doing, OK.
> 
> Thanks for the info anyway.


It's not about precise, it's about measuring humidity, the cheap way. 

Cheers!


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## etsherman (Aug 2, 2011)

What is the correct scientific answer to something I noticed while using misters on my outside a/c unit?

At the high temp portion of the day, 104 degrees, a/c exposed to full sunlight and with the misters on and adjusted to emitt the finest mist possible, why does the air feel colder coming out of the a/c vents including the ones farthest away from the blower/plenum? I am comparing this to say 80 degree temp at night when the sun has gone down. Seems the hotter/dryer it is ... the more efficient the misters are working!

Thanks,


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## supers05 (May 23, 2015)

Mostly placebo effect. 

With +250 posts, I'm not going back to look. I remember somewhere you had 20-ish *f delta T for no misters, and 19-ish *f with misters. Now you have 21.7*f. The human body can only detect a minimum 2-3*f difference in temp. 



Cheers!


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## SeniorSitizen (Sep 10, 2012)

etsherman said:


> What is the correct scientific answer to something I noticed while using misters on my outside a/c unit?
> 
> At the high temp portion of the day, 104 degrees, a/c exposed to full sunlight and with the misters on and adjusted to emitt the finest mist possible, why does the air feel colder coming out of the a/c vents including the ones farthest away from the blower/plenum? I am comparing this to say 80 degree temp at night when the sun has gone down. Seems the hotter/dryer it is ... the more efficient the misters are working!
> 
> Thanks,


https://en.wikipedia.org/wiki/Car_cooler


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## etsherman (Aug 2, 2011)

Thanks but in English please ... LOL


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## etsherman (Aug 2, 2011)

Ok, Swamp Cooler!


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## etsherman (Aug 2, 2011)

Question for the HVAC Guru's ... A while back you guys kept commenting that my return air was too cool because of two adjacent interior rooms with vents directly under the air handler and plenum. I explained that since those rooms are interior rooms with no exposure to sunlight and insulated ... they stay very cool regardless of the outside temperature and the temp in other parts of the house. I was informed that was incorrect and my return should never pull in cooler air as this makes the system inefficient.

The question I have is ... looking at my insulated air conditioned pet house ... here are the numbers:

A/C Misters = NO
A/C & House Shaded = Yes
Outside Temp = 101°
Thermostat Hold Temp = 86°
A/C Supply Temp = 55.9°
A/C Return Temp = 80.8°
Inside Temp = 85.7°

The inside temp is showing 90° in the picture because I had to unplug the thermostat for a few minutes to get it down from the ceiling in order to take a picture. It was showing 85 degrees when I first unplugged it.

Now, isn't this little window a/c unit doing exactly the same thing as my return connected to the central a/c unit inside the house??? Naturally it will pull in some cooler air that's closest to the intake vents ... wouldn't that be expected??? IJS


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## supers05 (May 23, 2015)

It's engineered to throw the air and cause mixing in the space. Window ACs aren't the most efficient, there's only so much you can do with the dimensions that they have to work with. However, with a larger room, you'll get very little short cycling of air. In a smaller space like your doggy house, then it'll short cycle a bit. (Mostly from the air hitting the far wall and recycling.) 

Most window shakers have their thermostat mounted to the return grill. It isn't the best temp to sense in smaller rooms because of the short cycling. Now premium units have a separate thermostat so that you can get a better sample of the space temp. 

PS. Neat idea to have the roof hinged. 

Cheers!


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## digitalplumber (Jul 8, 2011)

OK you have a window unit in the dog house? So how much of that needs to be deducted from your light bill?


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## beenthere (Oct 11, 2008)

Window units are known to pull in some of their own supply air. Its not something they design it to do to make it work better, or right. Its a flaw that is too hard for them to eliminate.


Next, if you have the thermostat mounted on the ceiling, its probably also picking up some radiant heat from the ceiling/roof. And may be showing a higher temp than the dog house really is.


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## etsherman (Aug 2, 2011)

supers05 said:


> It's engineered to throw the air and cause mixing in the space. Window ACs aren't the most efficient, there's only so much you can do with the dimensions that they have to work with. However, with a larger room, you'll get very little short cycling of air. In a smaller space like your doggy house, then it'll short cycle a bit. (Mostly from the air hitting the far wall and recycling.)
> 
> Most window shakers have their thermostat mounted to the return grill. It isn't the best temp to sense in smaller rooms because of the short cycling. Now premium units have a separate thermostat so that you can get a better sample of the space temp.
> 
> ...


I guess at some point any residential a/c system return air vents will pull in a certain amount of cooler inside air. As long as it is redistributed to the conditioned air space I don't see how that makes the system that much inefficient!!!

Yes, the hinged roof works very well. At first I had problems with the shingles folding and cracking at the hinged joint after so many openings & closings. Then I added a flexible rubber roofing membrane over the hinged joint (with no shingles there) and it works like a charm ... no leaks and no cracking!!

Thanks!!!


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## etsherman (Aug 2, 2011)

digitalplumber said:


> OK you have a window unit in the dog house? So how much of that needs to be deducted from your light bill?


LOL ... not much digitalplumber ... with the inside thermostat set to 86° and the dog house plus the a/c sitting in the shade 95% of the day ... the unit may run for a combined total of say 10 minutes over a 24 hour period of time. When it does turn on ... the cycles are very short ... most of the time less than 1 minute.

Thanks ...


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## etsherman (Aug 2, 2011)

beenthere said:


> Window units are known to pull in some of their own supply air. Its not something they design it to do to make it work better, or right. Its a flaw that is too hard for them to eliminate.
> 
> 
> Next, if you have the thermostat mounted on the ceiling, its probably also picking up some radiant heat from the ceiling/roof. And may be showing a higher temp than the dog house really is.



I agree ... but that's the nature of window units ... no system is perfect.


Yes, that's exactly why I mounted it in the ceiling. If I mounted it down lower the unit would almost never turn on, plus the dogs will bite off the little external wire probe that sticks out of that plug in thermostat. All the electrical boxes for the heater as well as the a/c unit are mounted in the ceiling for that specific reason.

Thanks,


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## supers05 (May 23, 2015)

etsherman said:


> I guess at some point any residential a/c system return air vents will pull in a certain amount of cooler inside air. As long as it is redistributed to the conditioned air space I don't see how that makes the system that much inefficient!!!...


No. The house more then large enough to allow for full mixing, long before reaching the return. The air entering the return of an AC dominate climate should be the warmest air in the house. (you don't get that choice with a window shaker.) Ideally, you'd have a return(s) for cooling and an equal number of returns for heating. 

Cheers!


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## beenthere (Oct 11, 2008)

etsherman said:


> LOL ... not much digitalplumber ... with the inside thermostat set to 86° and the dog house plus the a/c sitting in the shade 95% of the day ... the unit may run for a combined total of say 10 minutes over a 24 hour period of time. When it does turn on ... the cycles are very short ... most of the time less than 1 minute.
> 
> Thanks ...





If it runs less than 10 minutes a day. Then it is a window unit that is not serving any real purpose.


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## user_12345a (Nov 23, 2014)

> Most window shakers have their thermostat mounted to the return grill. It isn't the best temp to sense in smaller rooms because of the short cycling. Now premium units have a separate thermostat so that you can get a better sample of the space temp.


Best to use an external plug in thermostat on window units, i think one is in the picture.

More accurate gauge of room temp plus shuts the fan between calls for cooling. Yah, i know most have energy saver function but the sensor is really inaccurate with the fan off.

lux win100 i believe.


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## supers05 (May 23, 2015)

user_12345a said:


> Best to use an external plug in thermostat on window units, i think one is in the picture.
> 
> More accurate gauge of room temp plus shuts the fan between calls for cooling. Yah, i know most have energy saver function but the sensor is really inaccurate with the fan off.
> 
> lux win100 i believe.


Most people generally don't care when it comes to window shakers. They make cold air, and noise, and was cheaper to buy. That's generally all the average person cares about. 

They couldn't care about how even the temp is, or how much electricity they are using. 

Cheers!


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