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-   -   Upstairs Won't Cool Well (http://www.diychatroom.com/f17/upstairs-wont-cool-well-146841/)

theparamount 06-12-2012 02:57 PM

Upstairs Won't Cool Well
 
Hey all,

First post, but I've been reading for a while. Here's my situation:

Just moved into a 1 story Ranch. Fully finished basement.

Its been pretty warm (80-90) where I'm living and the A/C (forced central air) is giving me some issues. Upstairs, there are essentially 6 rooms, LR, Kitchen, 3 BR, and a bath. Each bedroom has a baseboard register and directly across the room is a cold air return. The living room has 2 baseboard registers and a large air return and the kitchen only has an air return. The thermostat is located in the hallway about 5 feet up on the wall. I set the thermostat at around 77. The air coming out of the registers is very cold air but it takes 3-4 hours for the temperature in the house to drop 1 degree from 78 to 77. And all the meanwhile, the first few feet of air are cold and the air above that are warm.

My questions:

1) How can I get the air to mix better upstairs since the air seems to cool a few feet and then go back into the cold air return?

2) How can I cool the hottest room in the house, the kitchen, which has no register?

3) Is it normal to take 3-4 hours for a house to cool 1 degree?

Thanks.

Marty S. 06-12-2012 05:40 PM

1)Move the returns higher up on the wall if possible. If it's an old house with the returns on outside walls then move the supplies up high.
2)Kitchens and bathrooms should not have returns,only supply air.
3) Yes it's quite common for houses that have both supply and returns on the floor to have crappy cooling. Most of the time there's just not enough throw to get the cool air mixed with the warm upper air so it falls to the floor and gets sucked right up by the returns. As the return gets colder and colder the capacity of the system keeps getting lower right along with it.

Lots of work to make it right but you can do it.

theparamount 06-12-2012 05:53 PM

Quote:

Originally Posted by Marty S. (Post 941986)
1)Move the returns higher up on the wall if possible. If it's an old house with the returns on outside walls then move the supplies up high.
2)Kitchens and bathrooms should not have returns,only supply air.
3) Yes it's quite common for houses that have both supply and returns on the floor to have crappy cooling. Most of the time there's just not enough throw to get the cool air mixed with the warm upper air so it falls to the floor and gets sucked right up by the returns. As the return gets colder and colder the capacity of the system keeps getting lower right along with it.

Lots of work to make it right but you can do it.

Marty

1) Is there any way to just use air deflectors on the registers to try and blow as much air up as possible?

2) Will moving the returns higher on the wall affect the heating of the house during the winter months?

3) Any way to rig something without tearing down the drywall that will allow the return air to pull from closer to the ceiling?

I guess the kitchen was not installed well then because it only has an air return and no register.

What do you mean by the capacity of the system getting lower and lower? I mean, I'm worried that the house wont cool below 76 degrees solely because the air near the thermostat doesn't circulate into the return air.

hvac instructor 06-12-2012 07:44 PM

couple of things come to mind.
1-did they add duct for the finish basement. that can be steeling air for the upstairs.
2- if they did add duct for the basement, they could have altered the duct design and you could have lost the static pressure and this will not give
you the throw of air into the room.
3-how well is the house insulated?
4-undersized a/c unit or oversized duct work.
i have a finish basement and in the summer all the vents are closed
and it it still colder that upstairs.

theparamount 06-12-2012 07:47 PM

Quote:

Originally Posted by hvac instructor (Post 942066)
couple of things come to mind.
1-did they add duct for the finish basement. that can be steeling air for the upstairs.
2- if they did add duct for the basement, they could have altered the duct design and you could have lost the static pressure and this will not give
you the throw of air into the room.
3-how well is the house insulated?
4-undersized a/c unit or oversized duct work.
i have a finish basement and in the summer all the vents are closed
and it it still colder that upstairs.

There are 3 vents that come off to heat/cool the downstairs. I completely blocked all three of them although the downstairs is always significantly cooler. Runs about 68 degrees since we've moved in.

I'm honestly not sure how well the house is insulated.

I dont know if there is a ton I'm going to want to do which is why I'm wondering whether an air deflector or something would help out. Also, can I just block all the air returns upstairs and just allow the downstairs air return to supply the furnace?

beenthere 06-12-2012 08:45 PM

Quote:

I dont know if there is a ton I'm going to want to do which is why I'm wondering whether an air deflector or something would help out. Also, can I just block all the air returns upstairs and just allow the downstairs air return to supply the furnace?
Air deflectors can help.

Blocking the returns will decrease total air flow, and probably freeze up the coil.

theparamount 06-12-2012 08:50 PM

Quote:

Originally Posted by beenthere (Post 942109)
Air deflectors can help.

Blocking the returns will decrease total air flow, and probably freeze up the coil.

Alright. I will buy some at Lowes tomorrow. I really hope it helps, but if not would the best thing be to move the air return? (will that affect winter heating?).

Thanks so much for your knowledge guys.

beenthere 06-12-2012 08:55 PM

Pics would help us to know better what your set is.

theparamount 06-12-2012 10:00 PM

Quote:

Originally Posted by beenthere (Post 942123)
Pics would help us to know better what your set is.

Pics of the furnace or the vents or ducts or what?

beenthere 06-12-2012 10:59 PM

The return and supply registers. Pics of the ducts won't hurt either.

hvac instructor 06-13-2012 06:31 AM

a good hvac co can check out the system and maybe balance it. there are air flow meters that they use. also there are companies out there thats all they do.

sixspeed 06-13-2012 10:12 AM

Quote:

Originally Posted by theparamount (Post 942001)
Marty

I guess the kitchen was not installed well then because it only has an air return and no register.

Quite possible that base cabinetry or appliances are concealing the supply registers. If cabinetry is installed along the exterior perimeter of the walls/floor where supply registers normally appear, there should be extended ducting to direct air into the room from unblocked registers in the toe-kick area or exposed floor. You can check whether any supply ducts were installed to the kitchen if basement area below kitchen is unfinished.


As for the other rooms, maybe an oscillating fan may help to merely mix the air better...

theparamount 06-13-2012 04:55 PM

Okay here are some pics:

BR Return

http://www.picstation.net/thumbnails...e5ea519733.jpg

BR Register (all three BR Looks the same in regard to the return/register)

http://www.picstation.net/thumbnails...7f5bc041a1.jpg

LR Register

http://www.picstation.net/thumbnails...6cbfe9691a.jpg

Another LR Register

http://www.picstation.net/thumbnails...cbf93a2775.jpg

Thermostat

http://www.picstation.net/thumbnails...71eb881ef2.jpg

LR Return

http://www.picstation.net/thumbnails...d1ba3d4a7a.jpg

Evstarr 06-13-2012 05:02 PM

You could install ceiling fans to mix the air better in the bedrooms. In our house we close the downstairs supplies in the summer and the upstairs supplies in the winter. It's a bit ghetto but surely is cheap. Lol

beenthere 06-13-2012 05:53 PM

Remove your air filter as a test, and see if the air comes out of the supply registers better. If it does, you need more return. if it doesn't your supply ducts are too small.

Might also want to check and see if your blower is on high speed in cooling mode.


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