Author Topic: Air Return in basement - open or closed when AC running?  (Read 4934 times)

Offline lyonsnet

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Air Return in basement - open or closed when AC running?
« on: July 20, 2008, 10:57:43 AM »
Hi,
I have a 4 bedroom 2 story 2100 sqft 4 year old home with an unfinished basement. My system is forced air.

There are 5 return grates, 2 on the second floor in the 2 larger bedrooms (high near the ceiling), 2 on the main floor (lower to the floor) and 1 in the basement (high, near the ceiling).

Overall, the AC is able to cool the main floor and second floor pretty well, though the second floor is 1-2 degrees warmer than the main floor. This is expected I assume.

I had a discussion with my neighbor, who has a similar home to mine. Since my basement is much cooler than the main and second floors, he recommends I close off the 3 vents in the basement to allow more cool air to the rest of the house. He also suggested I open the air return in the basement, to allow more cool air to enter the system, making the AC not have to work as hard.

My question, is the recommendations on closing the basement vents and also opening the return in the basement correct?

It sounds ok to me, except I am wondering what the impact will be for the returns on the second floor? I was thinking this may cause more warm air to remain on the second floor, not being returned to the AC.

Can anyone comment or have another suggestion?

Cheers,

Offline Admin

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Re: Air Return in basement - open or closed when AC running?
« Reply #1 on: July 23, 2008, 04:47:38 PM »
I wouldn't block any returns.  Block the supply vents in the basement, and force the cold air upstairs.
Leave the indoor fan running continuously, turn the thermostat from AUTO to ON.  This will constantly pull the cold air in the basement thru the open return and circulate the air upstairs.

Your neighbor has it right ;)

Offline oldguy2

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Re: Air Return in basement - open or closed when AC running?
« Reply #2 on: July 27, 2008, 04:36:15 AM »
i;ve been taught to block the vents in the basement even the return airs.the cold air will naturally fall to the lowest point so if its picking up colder air it would chile off your latent heat being picked up elsewhere from the returns there for not getting ride of the heat in the house