# A/C Doesnt Cool more than 20 Degrees.



## JJboy (Oct 12, 2010)

Yes, by design, he's right. The problem is today's temps are above the design temp. 
You need to leave your AC running all day and night. AC needs time to remove all the heat inside your house.


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## gregzoll (Dec 25, 2006)

If the unit is in the attic, did the tech go up there to see if any of the ducts are leaking, or critters have torn the insulation off? Also, did he check to make sure that the a-coil in the air handler/furnace & outside unit are clean? Did you go back and check the temps yourself with another thermometer 24 hours later at the closes vent to the furnace, and the return?


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## dbower (Dec 17, 2010)

JJboy said:


> Yes, by design, he's right. The problem is today's temps are above the design temp.
> You need to leave your AC running all day and night. AC needs time to remove all the heat inside your house.


Yeah, its pretty much on all day and night. Inside temp never gets more than 20 degrees less than outside temp.


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## dbower (Dec 17, 2010)

gregzoll said:


> If the unit is in the attic, did the tech go up there to see if any of the ducts are leaking, or critters have torn the insulation off? Also, did he check to make sure that the a-coil in the air handler/furnace & outside unit are clean? Did you go back and check the temps yourself with another thermometer 24 hours later at the closes vent to the furnace, and the return?


He did clean the coils on the inside unit. Said they didnt need a deep clean, just did a surface clean. Been running the thing day and night for weeks, never gets more than 20 degrees cooler in the house than it is outside.


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## JJboy (Oct 12, 2010)

We need these temps to be able to troubleshooting your AC.

Temp outside close by the condenser:
Temp 1st floor:
Temp 2nd floor:
Temp on the return:
Temp just after Evap coil: (inside the duct)
Temp on the supply register close to evap coil:
Temp on the supply register far away the evap coil:


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## gregzoll (Dec 25, 2006)

That as mentioned before is the design. How old is the unit, and how many tons is it? If you do not know, you can post model # and manufacturer, same for the indoor unit. If it gets over 95 outside, my system can hold the temp at 72, but it will never shut off during the day. Get all of the info as JJBoy stated, and the info I posted. If you do not have a decent thermometer, you can get a thermometer at bed, bath, beyond, target, wal-mart that reads from 20 to 120 like this http://www.bedbathandbeyond.com/product.asp?SKU=17712772


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## Technow (Nov 12, 2010)

The difference between OUTDOOR and INDOOR Temperature can be ANY Temperature difference....there is NO 20 degree LIMIT.

The temp difference between Supply Air and Return are IS typically 16-20 degrees depending on conditions.

Richmond VA Design temp 92.... 92-75 = 17 degrees design

Dallas TX Design 98....98-75 = 23 degrees design

In dallas at 108...then 85 is all it should do if the unit is sized perfect to maintain 75 degrees at the thermostat on a 98 degree day, but most ac's are oversized.


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## dbower (Dec 17, 2010)

I will get all the info requested this weekend. As far as measuring the temperature... is there a special thermometer i need to purchase to do this?

Thanks for all the help!


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## gregzoll (Dec 25, 2006)

No, just as I previously mentioned, a kitchen thermometer that allows you to read 20 degrees or below, to at least 120. Mine I got at Target in the Kitchen section. Originally for use in the kitchen, but comes in handy to check air temps. Same type like chef's use, that you see in their pockets.


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## dbower (Dec 17, 2010)

gregzoll said:


> No, just as I previously mentioned, a kitchen thermometer that allows you to read 20 degrees or below, to at least 120. Mine I got at Target in the Kitchen section. Originally for use in the kitchen, but comes in handy to check air temps. Same type like chef's use, that you see in their pockets.


Okay got it, thanks!


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## gregzoll (Dec 25, 2006)

I just checked mine, it goes from 0 to 220.


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## AllanJ (Nov 24, 2007)

The air has to make several trips through the air conditioner to be brought down to room temperature, especially if the AC has been off during the day and you turn it on when you get home after work. If outside air gets sucked into the system or when additional heat diffuses in through the walls, ceiling, etc. the air picks up that heat and needs even more trips through the AC unit.


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## Marty S. (Oct 31, 2009)

dbower said:


> Had a tech tell me that my unit is unable to cool my house more than 20 degrees less than outside temperature... He put a thermometer in the vent, and showed me the air temp coming out of vent was 80 degrees, its 100 degrees outside.
> 
> Is this correct? I dont remember it being this dang hot in my house in the past. He said Freon was good, everything was ok. Could something else have changed to be causing my house to be so hot? Something in the programming, or the Thermostat? Leak in the Duct in the Attic?
> 
> ...


If your design temp is 98 and it was 100 out the the supply air should be a lot cooler then 80 degrees. Good chance the duct leak in the attic guess is correct. Those few hours a day it hits the 100+ you'll lose ground but the system should catch back up in the evening.


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## yuri (Nov 29, 2008)

_"Its been been getting up to *108 *here in Texas...inside of house is almost 90 degrees."

_108 good grief. I think I will stay where I am and just add a few sweaters when it get snowing and real cold. Can always add more layers but not undress too far.:help:


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## biggles (Jan 1, 2008)

is the air handler getting a true return air from the conditioned spaces no attic air..80 supply air is garbage forget the outside temps the air handler should be dropping the return air 18F within the house are your floor wall getting blasted by direct sunlight?,do you have ceiling fans? normal 8'ceilings? are you seeing a good condensation run off from the air handler? is the condenser in the direct sunlight? grab the raw copper line coming out on the hottest of days and let use know what you feel temp wise....


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## Marty S. (Oct 31, 2009)

Was 105 this week here Yuri, heat index 115 or something crazy like that. Turned our AC up because it felt too dang cold in the house after working in that heat all day. Actually had the shivers and chicken skin. Another 4 months and it will be -30F windchill time.


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## yuri (Nov 29, 2008)

Its hard for me to imagine a unit being maxed out to its design temp and only being able to keep a house 80 degrees due to the extreme load. We may hit 90 a few times a year but it cools off at night so keeping a house 70-72 is no problema. Home is where you hang your hat/what you are used to/what your body is acclimatized to. We do get a lot of immigrants from the Philippines, Africa etc and they don't die the first Winter so it is possible to go to a very cold climate and not run back home. Doubt if I could stand high humidity, hot temps yes as I used to cycle outdoors in them. Being in Orlando for 3 days in that heat and humidity is not where I could live, nice to visit though.


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## dbower (Dec 17, 2010)

Got home late after the sun started to come down... so it was a cool 80 degrees in the house...

Outside unit is: CLJ36-1A
Inside unit is: A-43-15

Temp outside close by the condenser: 103.5
Temp 1st floor: 82
Temp 2nd floor: n/a
Temp on the return: 78
Temp just after Evap coil: (inside the duct) (didnt measure)
Temp on the supply register close to evap coil: 57
Temp on the supply register far away the evap coil: 57.9


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## REP (Jul 24, 2011)

You have to be aware of two distinct things with a/c
The first is that any unit should be able to cool the house air by 20 degrees.
The second is the construction and insulation of the house.
If you have enough insulation to prevent outside temps from invading the house then the a/c could take house air and drop it 20 degrees all day long until it was freezing in the house.But because no house is perfectly sealed thenif your a/c knocks twenty degrees off of the house temp,say 100 degrees down to 80 degrees and then insulation allows the house to pick up 5-10 degrees then the a/c sees 85-90 degrees and lower it to 65-70 degrees.
Now since hot temps goes to cold tempatures and the bbigger the differance between the two tempatures the faster the travel of hot to cold is true then if a house is designed to hold the house at 78 with a design outdoor temp of 98,you lose more cooling when the outside tempature rises to 108. Under design sizing your house will if sized perfectly only hold the house temp to 88 degrees at 108 outside tempatures. and if your duct system is sized correctly and well insulated.
Any changes will affect design i.e. if you have more insulation and the best windows you could in the same house be able to hold cooler tempatures.If on the other hand if the duct system is loose or not insulated well then your system will allow the inside tempatures to be higher than design.
There is a lot here for you to wrap your mind around but it contains the whole truth about what tempatures you can expect inside your house.


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## JJboy (Oct 12, 2010)

REP said:


> You have to be aware of two distinct things with a/c
> The first is that any unit should be able to cool the house air by 20 degrees.
> The second is the construction and insulation of the house.
> If you have enough insulation to prevent outside temps from invading the house then the a/c could take house air and drop it 20 degrees all day long until it was freezing in the house.But because no house is perfectly sealed thenif your a/c knocks twenty degrees off of the house temp,say 100 degrees down to 80 degrees and then insulation allows the house to pick up 5-10 degrees then the a/c sees 85-90 degrees and lower it to 65-70 degrees.
> ...


VERY NICE explanation. This should be sticked. :thumbup:


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## dbower (Dec 17, 2010)

Checked around in the attic... didnt notice any leaks in the duct. 

BUT... 10 years ago we had the garage converted. We sprayed insulation in the attic above the new room, looking at it now... looks that insulation has settled quite a bit. Thinking that may be the problem, or at least part of it. 
We also put insulation in the walls, which I'm sure has settled by now as well.

That room has always been a bit warmer than the rest of the house (or cooler in the winter). They only put one supply register out there, and its a big room.


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## Technow (Nov 12, 2010)

dbower said:


> Checked around in the attic... didnt notice any leaks in the duct.
> 
> BUT... 10 years ago we had the garage converted. We sprayed insulation in the attic above the new room, looking at it now... looks that insulation has settled quite a bit. Thinking that may be the problem, or at least part of it.
> We also put insulation in the walls, which I'm sure has settled by now as well.
> ...


10 years is a long time ago, but was the clj36 sized for the additional room, just a guess but 1 outlet in a converted garage doesn't sound like enough. How old is the unit?


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## dbower (Dec 17, 2010)

Technow said:


> 10 years is a long time ago, but was the clj36 sized for the additional room, just a guess but 1 outlet in a converted garage doesn't sound like enough. How old is the unit?


The unit is about 10 years old. Garage was converted a year later.


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## REP (Jul 24, 2011)

One run is fine if its the right size.What I would be concerned with is you haven't talked about a return air grille in that room.
If there is no return air grille then its like blowibng as hard as you can into a soda bottle.No matter how hard you try.you will not get any new air into that bottle. Now if you put a hole in that bottle and blow then you will get all the air you want into that bottle because the old air has someplace to go.


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## dbower (Dec 17, 2010)

REP said:


> One run is fine if its the right size.What I would be concerned with is you haven't talked about a return air grille in that room.
> If there is no return air grille then its like blowibng as hard as you can into a soda bottle.No matter how hard you try.you will not get any new air into that bottle. Now if you put a hole in that bottle and blow then you will get all the air you want into that bottle because the old air has someplace to go.


Not sure about that, the door to that area is usually open...

Here's the info someone asked for earlier... Anyone have any thoughts on that? Looks like the AC is doing its job. Really thinking its an issue with insulation above the garage, and around the attic stairway.

Outside unit is: CLJ36-1A
Inside unit is: A-43-15

Temp outside close by the condenser: 103.5
Temp 1st floor: 82
Temp 2nd floor: n/a
Temp on the return: 78
Temp just after Evap coil: (inside the duct) (didnt measure)
Temp on the supply register close to evap coil: 57
Temp on the supply register far away the evap coil: 57.9


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## JJboy (Oct 12, 2010)

dbower said:


> Not sure about that, the door to that area is usually open...
> 
> Here's the info someone asked for earlier... Anyone have any thoughts on that? Looks like the AC is doing its job. Really thinking its an issue with insulation above the garage, and around the attic stairway.
> 
> ...



AC is OK:thumbsup:


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## dbower (Dec 17, 2010)

JJboy said:


> AC is OK:thumbsup:


Thanks JJboy! Its got to be an issue with not enough insulation above converted garage. It is always hotter (or colder in the winter), than the other rooms.

Do ya'll recommend the ATTICAT blow in insulation? Think thats the route Im going. Also, found some plans for homemade Attic Stair covers, anyone have one they recommend?

Thanks again for everyone's suggestions and input!!:thumbsup:


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## REP (Jul 24, 2011)

It appears that the a/c unit is working fairly good.
The next step would be to get the insulation upgraded.
Normally I am not a big fan of gun type tempature readers but in this situation it might tell you how far the insulation has settled.
Don't forget about insulating the ductwork.
Also just remember if that door gets closed you have the soda bottle affect.


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## dbower (Dec 17, 2010)

Thanks for the input Rep. As far as insulating the duct... Do you suggest blowing enough insulation that it covers the duct? Or is there something I can wrap around it?

I believe the ductwork up there now, has insulation built in. Its the flexible hose type...


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## JJboy (Oct 12, 2010)

dbower said:


> Thanks JJboy! Its got to be an issue with not enough insulation above converted garage. It is always hotter (or colder in the winter), than the other rooms.
> 
> Do ya'll recommend the ATTICAT blow in insulation? Think thats the route Im going. Also, found some plans for homemade Attic Stair covers, anyone have one they recommend?
> 
> Thanks again for everyone's suggestions and input!!:thumbsup:


I converted my garage in photography studio. I have the same problem. I installed 1T portable AC. I did load calculation and I need 2T due of the garage doors. Only in summer the portable AC is not able to cool down properly


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## Master of Cold (Aug 7, 2011)

yuri said:


> Its hard for me to imagine a unit being maxed out to its design temp and only being able to keep a house 80 degrees due to the extreme load. We may hit 90 a few times a year but it cools off at night so keeping a house 70-72 is no problema. Home is where you hang your hat/what you are used to/what your body is acclimatized to. We do get a lot of immigrants from the Philippines, Africa etc and they don't die the first Winter so it is possible to go to a very cold climate and not run back home. Doubt if I could stand high humidity, hot temps yes as I used to cycle outdoors in them. Being in Orlando for 3 days in that heat and humidity is not where I could live, nice to visit though.


Don't let our weather bother you too much. Next time you come down let me know. You can spend the day with me on top of the mall ;-)


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