# Acceptable to install whole-house evaporative cooler with only a single supply vent?



## iLikeDirt (Apr 27, 2014)

My new house has a 20+ year old evaporative cooler on top of the roof. The cooler is ancient and rusted, difficult to service due to the location, and the forced air heating ductwork it feeds into is undersized for the volume of air it pushes. I would like to replace the unit with a (surprisingly inexpensive) new, highly efficient evaporative cooler mounted at ground level that blows air straight through a wall. The cooler would sit in the shade and have a short, straight duct going right through an exterior wall and into the main living/dining/kitchen area.

My hope is due to the direct installation, I could get a very low level of static pressure and choose a small, energy-efficient 1/3 horsepower motor. However, I worry about this installation being able to serviceably cool the entire house (≈ 1100 sf) with all of the air coming through only a single supply vent.

I think I would be able to get adequate airflow into the bedrooms by opening bedroom windows but NOT opening windows in the living/dining/kitchen area, thereby forcing the flow through the main living area, down the hall, and out through the bedrooms.

Does this sound like it would work? Is there some kind of chart or formula for determining the required CFM of the blower given a static pressure value, a square footage, and/or (pipe dream) a house layout? Should I just get a bigger cooler or motor for some wiggle room and be done with it? I would prefer the more efficient, better designed approach. ;-)


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## sammy37 (Dec 9, 2008)

What you describe, works great and is the best way to set a cooler up. You dont have that many square feet to cool, so a 4,500 cfm cooler would be just fine. What part of the country are you in?
I prefer to have an even bigger cooler and just slow it down by opening the motor pulley bigger, you get a little bit cooler air and less noise from the unit.


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## SeniorSitizen (Sep 10, 2012)

I grew up with a swamp cooler in a window. Works well in a dry climate. If your bedrooms have double hung windows pull the uppers down during the day to allow warmer upper air to escape.


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## iLikeDirt (Apr 27, 2014)

Thanks guys. The climate is central New Mexico, so it's just right for an evaporative cooler, and all the houses and businesses around here have them. If a wall vent is appropriate, would it make sense to have the opening higher up on the wall (after all, cool air falls), or does it not really matter?

I'm looking at MasterCool models with the rigid media; if higher up on the wall is better, I'm thinking that an updraft model with an elbow to direct the air into the vent toward the top of the wall would make the most sense. Is the MasterCool a good cooler, or can folks recommend a better one?

One more question: the spec sheet for this model (http://www.essickair.com/wp-content/uploads/2010/11/ss_ResMastercool.pdf) has real-world CFM ratings at various levels of static pressure. Would that be the external static pressure, or the total static pressure (i.e. including that imparted by the pads in the cooler)? Because I'm thinking that the external static pressure of a cooler ducted basically straight through a wall should be very low, right?


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## beenthere (Oct 11, 2008)

Yes the static in one short straight duct shouldn't be much. but its not just the static through the wall duct. Its also the static built up in the house varied by the size and number of open windows.


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Thanks guys. The climate is central New Mexico, so it's just right for an evaporative cooler, and all the houses and businesses around here have them. If a wall vent is appropriate, would it make sense to have the opening higher up on the wall (after all, cool air falls), or does it not really matter?
> 
> I'm looking at MasterCool models with the rigid media; if higher up on the wall is better, I'm thinking that an updraft model with an elbow to direct the air into the vent toward the top of the wall would make the most sense. Is the MasterCool a good cooler, or can folks recommend a better one?
> 
> One more question: the spec sheet for this model (http://www.essickair.com/wp-content/uploads/2010/11/ss_ResMastercool.pdf) has real-world CFM ratings at various levels of static pressure. Would that be the external static pressure, or the total static pressure (i.e. including that imparted by the pads in the cooler)? Because I'm thinking that the external static pressure of a cooler ducted basically straight through a wall should be very low, right?


That cooler will be fine as it has a plastic liner in the wet section. The one thing I dont like about that cooler is the pump, buy a Dial brand replacement for 30 bucks when you install the cooler.
The only reason for mounting the air outlet in the room up higher, would be to keep people out of the path of air, otherwise it wont make a difference in cooling and you may have to pay extra to order an updraft model, as the big box stores dont stock that model.
Dont stress too much over static pressure, either the small or large model of that cooler will be just fine for your home.
Also be sure to install a purge(dump) pump in the cooler if it doesnt come with one, it will lengthen the life of the pads greatly and they dont waste as much water as a constant bleed off.


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## iLikeDirt (Apr 27, 2014)

Thanks sammy. Would you recommend a different one, or will the MasterCool be fine with a better pump and a purge system?

One more thing: will it be beneficial to install the cooler in an exterior location where it's shaded for much of the day?


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Thanks sammy. Would you recommend a different one, or will the MasterCool be fine with a better pump and a purge system?
> 
> One more thing: will it be beneficial to install the cooler in an exterior location where it's shaded for much of the day?


Its been pretty much detirmined that shade doesnt do much for a cooler but it may ease the mind.
The original maker of Mastercool, Adobe air, went out of business years ago and they were the best. Champion bought the name and their version is not as good but there arent too many choices left out there.

My favorite cooler is the Bonaire Durango unit from Australia, Home Depot sells them. They are made out of strong plastic and because they use a fan instead of a blower, they only protrude from the house 10 inches. Also, because its only turning a plastic fan blade, it uses much less electricity with a smaller motor, I think somewhere around 400 watts on high speed. Dont let the small fan fool you, it moves a ton of air and will cool a house bigger than what you have. They also have a 3 speed motor, something you cant get with a standard cooler.

I have installed many of these in Vegas and for the wall mount setup you are doing, that would be my first choice. They run a little less than 500 bucks complete.


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## iLikeDirt (Apr 27, 2014)

Holy moley, that thing looks amazing. Looks a ton easier to install than a big old ground-mounted unit, too. My house has 16" OC studs but that unit has a 22" duct though, which will complicate things for a permanent wall-mounted installation.


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Holy moley, that thing looks amazing. Looks a ton easier to install than a big old ground-mounted unit, too. My house has 16" OC studs but that unit has a 22" duct though, which will complicate things for a permanent wall-mounted installation.


Just cut the stud and frame around on each side. They have two models of that cooler now, the 4,500 model will be just fine for you, just installed the new version in a house last week. The new one comes with a louver kit for the grill and a remote control, also has a built in bleed off with a very small orifice that wont waste too much water.
Usually if a wall sleeve is smooth, I can cut the hole perfect and just run a nice bead of caulk around it to finish it off but this cooler does require cutting the hole a hair bigger, so you'll want to put a wood moulding trim around it on the inside of the house. Also remember that the sleeve will stick into the room a little, because you will want to shove the cooler completely against the wall on the outside.


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## iLikeDirt (Apr 27, 2014)

Thanks for the trim advice. I've never cut a load-bearing stud in an exterior wall before and am a little bit nervous… Obviously you can build a frame around the hole to transfer the load to the sill plate but is it a problem to have nothing bearing that load during the time between when you cut it and build the frame? Or am I just being paranoid?


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Thanks for the trim advice. I've never cut a load-bearing stud in an exterior wall before and am a little bit nervous… Obviously you can build a frame around the hole to transfer the load to the sill plate but is it a problem to have nothing bearing that load during the time between when you cut it and build the frame? Or am I just being paranoid?


I've been cutting holes in houses since I was a teen, no problems involved cutting one stud.
It's not like the wall is going to sag when you cut the hole, in fact nothing exciting will happen at all.


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## bobinphx (Nov 25, 2011)

Ive had evaps all my life. They are super nice (until the dew point gets too high!!). 

my suggestions. 

1. I would worry about the noise from 4500 cfm entering the living room. evaps are not quiet. You might think about adding a short duct and some sort of quieting blanket inside the duct. Please besure what ever you use does not produce any fibers or mold that would come into the house (example ductboard, I think)

2. Opening the right amount of windows is important. I was taught to take a dollar bill and put on the inside of the window screen and if it stays in place and does not slip down, you do not have enough windows open!. Of course outside wind could foul this up a bit, but it has worked for me. 

3. There is a company in phx that makes a stainless steel wet section for mastercool type systems. WORKS GREAT and no more rust worries. 

4. a bleed off is a must! you have to have clean water on the pads or they will clog and the hard water in az and NM will really eat everything up if it is allowed to distill into the natural salts in the water. 

5. security: a 16 by 16 whole in the house could be used by bad guys to gain entrance. besure the evap is very secure and cant be easily pryed out. The same goes for windows being open. I have all of my windows setup with keyed deadbolt type sliding window locks, top and bottom. The keys are close at hand if needed for egress. My kids are older and have been trained that in case of fire, bust what ever you have to in order to get out (including windows!!) because I will be very mad if they get burn up!!! Oh and when I leave, I close my windows and open my attic hatch so that the sort of cool exhaust air cools the attic.


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## sammy37 (Dec 9, 2008)

bobinphx said:


> Ive had evaps all my life. They are super nice (until the dew point gets too high!!).
> 
> my suggestions.
> 
> ...



Yes, can be noisy. The Durango cooler is almost silent on low speed and not too bad on medium. He may rarely use high speed.

I've used those stainless steel wet sections from down in Phoenix, converted a bunch of industrial aspen pad coolers with them. I've not been too happy with the water distributor design, or the water supply setup they use. I've talked to them before and they dont seem too interested in hearing about design issues.
I ordered 5,000 bucks worth of Celdek from them last year and they screwed up and cut them all two inches too short on the height!:furious:

The cooler the OP may consider, mounts directly to the wall and also fastens inside the house, no one would bother trying to pull it out to break into the house.


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## iLikeDirt (Apr 27, 2014)

Yeah, those Durango coolers look like really slick machines. I'm almost positive I'm going to buy one.

Do you happen to know how much electricity the two Durango models use at the various motor speeds? And how about the theoretical evaporative efficiency of their CELdek pads? They seem to use 2.5" pads while the MasterCool uses 12" pads and claims 90% efficiency. Those huge pads are wicked expensive though.


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Yeah, those Durango coolers look like really slick machines. I'm almost positive I'm going to buy one.
> 
> Do you happen to know how much electricity the two Durango models use at the various motor speeds? And how about the theoretical evaporative efficiency of their CELdek pads? They seem to use 2.5" pads while the MasterCool uses 12" pads and claims 90% efficiency. Those huge pads are wicked expensive though.


I'm not completely sold on the larger Durango cooler, as it uses the same cabinet size, pad size and fan size as the smaller cfm unit. This would tell me that they are just speeding up the cooler with a higher rpm fan and that to me would result in slightly warmer air and more noise.

I do know that the motor on high speed is somewhere in the 400 watt range, which is far better than the same sized belt drive cooler with 1/2 horse motor, they would be near the 900 watt range.

The Celdek in the Durango is much thinner but it is a high density Celdek, compared to the low density Celdek in the larger coolers. Saturation efficiency should be near the 90% range. I'll tell you one thing, the Durango cooler is wicked cold on a dry day. I was a bit dubious the first time I installed one and didnt think it would cool well at all but I was wrong, it felt as cold as the 12" Mastercool we were using at our house.


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## iLikeDirt (Apr 27, 2014)

Thanks for all the wonderful information, sammy. You've really sold me on this thing! Very exciting. It'll be nice to have a low-profile unit on the wall as opposed to a big old metal cabinet taking up space on the patio!


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## DavidDavis (Nov 8, 2012)

*Evap Cooling*

A single introduction will cool the space near the supply, but will likely be ineffective in rooms further from the supply. Dealt with evap cooling extensively as a Honeywell Tech in NM. The key to good evap cooling systems is powered exhaust. Get the air in, get it back out. If there were a room near the exhaust you wanted to focus on you could add an exhaust there.




iLikeDirt said:


> My new house has a 20+ year old evaporative cooler on top of the roof. The cooler is ancient and rusted, difficult to service due to the location, and the forced air heating ductwork it feeds into is undersized for the volume of air it pushes. I would like to replace the unit with a (surprisingly inexpensive) new, highly efficient evaporative cooler mounted at ground level that blows air straight through a wall. The cooler would sit in the shade and have a short, straight duct going right through an exterior wall and into the main living/dining/kitchen area.
> 
> My hope is due to the direct installation, I could get a very low level of static pressure and choose a small, energy-efficient 1/3 horsepower motor. However, I worry about this installation being able to serviceably cool the entire house (≈ 1100 sf) with all of the air coming through only a single supply vent.
> 
> ...


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## sammy37 (Dec 9, 2008)

[email protected] said:


> A single introduction will cool the space near the supply, but will likely be ineffective in rooms further from the supply. Dealt with evap cooling extensively as a Honeywell Tech in NM. The key to good evap cooling systems is powered exhaust. Get the air in, get it back out. If there were a room near the exhaust you wanted to focus on you could add an exhaust there.


I've found in my 30 plus years of dealing with coolers, that most people never opened windows enough in far away rooms. A lot of old timer still only go with the method of cracking a couple of windows but all you end up with is a humid house and far away warm rooms.
The OP's house isnt that big and if he opens the windows far enough in the bedrooms to be cooled, he will be just fine.


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## iLikeDirt (Apr 27, 2014)

sammy37 said:


> I've found in my 30 plus years of dealing with coolers, that most people never opened windows enough in far away rooms. A lot of old timer still only go with the method of cracking a couple of windows but all you end up with is a humid house and far away warm rooms.
> The OP's house isnt that big and if he opens the windows far enough in the bedrooms to be cooled, he will be just fine.


Yeah, and it seems that the better I air-seal the rest of the house, the better I'll be able to direct the flow of air. Right now, in order to get into the bedrooms, it will need to pass by the furnace closet that was super duper leaky before I weatherstripped the door (it gets its combustion air from the attic; don't worry, I'm not going to kill myself with carbon monoxide)


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## iLikeDirt (Apr 27, 2014)

Okay, so I bought a 4,500 CFM Durango and am preparing to install it. How high up in the wall do people typically install these? This one will be blowing right into the center of a kitchen/dining/living area. Should the grille be at head height? Waist height? Knee height?


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Okay, so I bought a 4,500 CFM Durango and am preparing to install it. How high up in the wall do people typically install these? This one will be blowing right into the center of a kitchen/dining/living area. Should the grille be at head height? Waist height? Knee height?


I just installed the larger model in house this afternoon. I put it in the lady's living room wall, right in the 6 to 7 foot range. The hole I cut was 19.75H by 20W. I cut the outside hole a couple inches larger, to facilitate easier framing and it works out fine, because the cooler sit right up against the wall.
The new coolers also come with a snap on louver kit for the grill and although it's quite ugly, it's effective for directing airflow.


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## iLikeDirt (Apr 27, 2014)

Hmm, that's pretty high up. How does she reach the controls? Entirely with the remote?


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## sammy37 (Dec 9, 2008)

iLikeDirt said:


> Hmm, that's pretty high up. How does she reach the controls? Entirely with the remote?


Yeah, If you leave the control knob to off and switch the lower toggle switch to remote, you can use remote only and thats what she opted to do. Her couch sits below the cooler, so she wanted it up higher.


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## Jerven (Jun 16, 2014)

Sammy37, I am looking to install one of the Bonaire Durango models in my manufactured house that is 1600sqft and sits in Ojai, Ca. Summer temps reach 100-110 degrees for months and my normal power bill for running AC is about $250. Which model size do you think would work best for me? It will be mounting it in the wall located in the middle of the house. My father in law is a contractor and would help with install. I am draw to the larger model just because of the adjustable louvers, possible thermostat, and remote control. I know you have recommended the smaller unit quite frequently, I don't know which model would be more productive and cost effective. Thanks Sean


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## PanamaJim (Jul 18, 2014)

sammy37 said:


> Its been pretty much detirmined that shade doesnt do much for a cooler but it may ease the mind.
> The original maker of Mastercool, Adobe air, went out of business years ago and they were the best. Champion bought the name and their version is not as good but there arent too many choices left out there.
> 
> My favorite cooler is the Bonaire Durango unit from Australia, Home Depot sells them. They are made out of strong plastic and because they use a fan instead of a blower, they only protrude from the house 10 inches. Also, because its only turning a plastic fan blade, it uses much less electricity with a smaller motor, I think somewhere around 400 watts on high speed. Dont let the small fan fool you, it moves a ton of air and will cool a house bigger than what you have. They also have a 3 speed motor, something you cant get with a standard cooler.
> ...


Sammy, could you please resend the link to the wall mount install? When I try, it goes to a DELL ad! Thanks


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## iLikeDirt (Apr 27, 2014)

FYI, I bought the Durango window unit and mounted it permanently through a wall in my main living area. So far, it has been doing a magnificent job of cooling the entire house, including the bedrooms, and it's even acceptable right now during the monsoon season.

For those interested in how to do the install, here's how I framed it:










I made a 19.5 x 20 square frame but would recommend to others that they make it 20 x 20.5 to facilitate shimming and leveling. Mine was juuuuuust big enough but it could easily have been too small.


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## PanamaJim (Jul 18, 2014)

Very nice! Very clean! I might add a cripple (jack) stud under the sill plate...one at each end. Just for peace of mind...


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## iLikeDirt (Apr 27, 2014)

PanamaJim said:


> Very nice! Very clean! I might add a cripple (jack) stud under the sill plate...one at each end. Just for peace of mind...


Thanks! The sill is very securely screwed into the trimmers and already has one cripple near the center. And the cooler itself is screwed into the frame on all sides. As a result, the sill is barely bearing any load at all. So I'm not too worried about it.


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## bgeery (Apr 1, 2015)

I just installed a Bonaire Durango through-wall in my uninsulated, 1000 sf, 1955 house. I love it! Installed in the bedroom, and it shoots straight down the hall to the rest of the house

It was 92 yesterday, and humidity was 10%. The Durango was blowing 58 degree, fresh, clean air. House dropped from 82 to 70 in under two hours. Ran it in fan only mode that night, to bring in the nice 56 degree night air.

I had to frame it with 2x3 because of the uneven stucco surface, and then fill the gap with spray foam. To match the depth of the plaster, and because I had to cut the diagonal corner brace, I used 1/4" drywall over 1/2" OSB. Once I finish the drywall and add 1x4 trim around the inside part of the unit, it will only stick out two inches into the room.

I didn't want the bleed water just draining next to the house (and have no use for it,) so I made a french drain from a 10 foot section of PVC with holes drilled in it the last 5 feet. Around the PVC I used a drain sock. Laid the PVC in a bed of 50 lbs of fine gravel, added another 50 lbs of gavel on top, and covered it all in another layer of drain sock material. Pipe tape was used to protect the above ground section of PVC.

I used a stainless braided water heater hose to connect the Durango to the drain line.

Total project cost was $800. SCE has a $200 rebate, dropping the total to $600.


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## bgeery (Apr 1, 2015)

Pics.


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## bgeery (Apr 1, 2015)

Can't edit posts? Anyway, someone asked for power consumption figures. Here they are for a 4500 CFM Bonaire Durango:

Fan mode. Watts / Volt-Amps / Power Factor:
Low 191 / 222 / .88
Med 251 / 287 / .87
High 325 / 400 / .81

Cooling Mode. Watts / Volt-Amps / Power Factor:
Low 207 / 245 / .84
Med 265 / 312 / .84
High 342 / 426 / .80


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## bgeery (Apr 1, 2015)

One feature lacking in the Bonaire Durango is the ability to have only the pump on, to pre-wet the pads. Thankfully, the manual includes a wiring diagram, and it was easy to figure out how to add the feature.
A $1.20 15 Amp toggle switch from eBay just fits next to the rest of the controls. The wire harness going to the motor runs right behind where the toggle switch is mounted. It's wired to the blue (neutral) wire. Cut the wire, added ring connectors and attached to the switch. There is just enough room to add the switch. If I did it again, I would move the switch down a tad more, removing the "OFF" part of the switch label.
Now I can turn it on cool mode to activate the pump, and use the toggle switch to disable the motor.


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## sammy37 (Dec 9, 2008)

The way I really prefer for any window or wall cooler, is to install a low voltage cooler thermostat kit. You probably already know that using a swamp cooler in the middle of the night will freeze the heck out of the place. I never did enjoy waking up to a 60 degree or colder house in the morning.

The one advantage to the Bonaire unit not having a pump only feature is, the pads seem to wet out quite quickly.


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