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jreid
03-24-2005, 10:10 AM
I am tapping into my HVAC system to provide conditioned air to my soon to be finished basement. The unit is sized to handle the added load. I have run my supply ducts on the outside walls about 6 inches off of the floor. Getting the returns in is difficult. I assume they need to be low to the ground in a basement and in the center of the room to draw cool air from the floor area. What is the best place for the returns?

Thanks

Tom R
03-24-2005, 01:59 PM
Trying to move this question to HVAC, - - but just keep getting 'invalid session'.

Cole
03-24-2005, 02:04 PM
weird.

Tom R
03-24-2005, 05:14 PM
Thank you, God!! :lol:

rabadger
03-24-2005, 06:32 PM
You put the supplies low on the outside walls so they blow across the floor. Am I correct or don't I have this pictured right?

If I am correct where is the return air duct for the rest of the home?

jreid
03-25-2005, 04:22 AM
rabadger, you are correct. The supplies are low on the outside walls to supply air low on the floor. My thoughts were warm air rises and I probably will be wanting more warm than cold air down in the basement.

The returns for the rest of the home are basically in every room but the kitchen and bathrooms. They are high on the walls pretty much opposite the supplies on the inside walls. While that seems right for the rest of the home, I felt putting returns low on the walls in the basement would pull the cool air from the floor and help pull the warmer air from the ceiling downward. If I put the returns high on the wall, it would seem to me that I would get stagnant air on the floors in the winter since the warm air from the supplies would rise pretty quickly and get recirculated if the returns were high on the wall.

roger g
03-25-2005, 06:10 AM
You always put the supplies under or near a heat loss (windows and doors) because heat escapes through there. Cold ( so "they" tell us) doesn't really come in but when more heat goes out than is being produced you will feel cold.
It seems that you have really good return air if you have one in almost every room. Excellent! I would keep my return air as low as possible for just the reasoms you say. Low on the wall or in the floor equally good and more to the centre of the house. One of the biggest heating problems is not enough return air. Lots of heat BTU's but not enough return. A quick really rough check is the count up the suare inches of supply and then the return. They should be very close.


roger

rabadger
03-25-2005, 06:54 AM
Put the returns center of room in ceiling. Puting them low with the supplies will short the air circulation. If the supplies are high in the ceiling put the returns low wall. You have to have air circulation through out the whole room. Upstairs the supplies are on the floor on outside walls and returns air inside walls high. Correct?

roger g
03-25-2005, 04:22 PM
I thought we were talking about heating? Heat rises and cold air drops. The way I was taught was that in HEATING you want to suck the cold air from the bottom which helps bring down the heated air which wants to rise. In a/c you want to suck off the hot air from the top which would help raise the cool air. It depends on where you live as to what you have as a longer season. Heating or cooling. Either way, if you design for one it really isn't designed for the other.
As an example: how can a house be deigned to put most of the heating on the colder north and west walls (where the heat loss in the greatest)in the winter and yet put most of the cooling air on the south side of the house (where you get the greatest heat gain) yet using the same ductwork.



roger

bkrahmer
03-25-2005, 08:54 PM
That's easy. Radiant in-floor for heating, central A/C for cooling. It's what I would do if I had to worry about much cooling, but I don't, so I left out the A/C in my house. :)

jreid
03-27-2005, 06:45 PM
So......................

What's the answer guys? One says high; one says low. I need to get this figured out quickly. I have two drywall guys waiting for my decision and I want to get it scheduled.

Thanks

HVACTexas
03-28-2005, 05:04 AM
With a standard ceiling height it won't make much difference whether the return is high or low. The space won't be comfortable anyway without a thermostat on that level.

roger g
03-28-2005, 06:18 AM
Run the ductwork through the stud space with an opening at the bottom and the top with closable grills. That way you can suck off the bottom in the winter and suck off the top in the summer.
In reality do what everyone else does so it doesn't look odd when you go to sell it. Life is a compromize.


roger

rabadger
03-28-2005, 09:11 AM
roger g is correct. without seeing a drawing combo high and low with dampers would be the best.