heat registers and return in ceiling

[trguitar]

I'm looking for ways to get more heat upstairs. I'm in a 2400 sf cape. I can heat the downstairs great -- easily into the 70s, but there is always about a 5-10 degree difference between downstairs and upstairs. It's not terrible having the upstairs in the low 60s (nice sleeping temps actually), but my wife is from LA and likes it warm!

I brought the attic up to R49 last year, and insulated the kneewalls properly which has made a big difference. I had an energy audit, too, and the guy said the ceiling was pretty good.

The house was originally built in the early 80s with electric panels in the ceiling. Sometime in the 90s it was retrofitted with central air fired by oil. I guess they wanted to cut corners (shocker) because they decided to bring the air up from the basement into the attic and down through the ceiling, to heat the upstairs rooms.

There is also a large return (20 x 25) in the ceiling right at the top of the stairs.

I shot my thermal gun at the return the other day and it was really warm! Like exactly the downstairs temp, but the ceiling around it was 5 degrees cooler. Same with the heat registers in the ceilings in the rooms upstairs. They are 5 degrees warmer than the surrounding area.

I blocked off the return with Saran Wrap, and it appears to be working better. Now I'm contemplating blocking the heat registers, too.

When the energy audit guy was here last year, he thought that blocking the return wouldn't make much of a difference, but I'm not so sure I agree.

Anyone do this? Anything to watch out for other than making sure to unblock everything when I turn the heat or A/C on?

Alex

 

[Nick Mystic]

So, you are thinking that the heat that makes it upstairs is being sucked out by the open registers and cold air return? You think that if you seal these up then the hot air up near the ceiling will build up and heat the rest of the room? Since you say when you shoot the registers with our IR meter they are warmer than the rest of the ceiling area. That set of facts makes me think that the opposite is taking place. Warm air from downstairs is making its way up through the duct work and exiting through the vents and cold air return. I suppose your proposal to seal them all up will put your hypothesis to the test. If you seal them all and the rooms get warmer you hit pay dirt. If they get cooler you'll know the opposite is likely occurring.

 

[daleeper]

I will add to Nick's post by saying that if you find out what direction the hot air is moving, using a booster fan on the vents may help. If the hot air is moving the same direction the furnace would be pushing it, then run the furnace air handler fan without the furnace kicking on for a while and see if that helps equalize the temperature between floors (hopefully heating upstairs, not cooling downstairs).

The other thing that comes to my mind is how well is the duct insulated from the lower level to the upper and across the attic? Make sure that the duct is under all that insulation you have added in the attic, otherwise a lot of heat is being lost right there.

Good luck and keep us posted.