|
|
Posted by Keith in Washington on Monday, February 02, 2009 at 22:57:09 :
In Reply to: Re: OT: Insulated the garage ceiling, Payback looks good posted by Gordon Maney on Monday, February 02, 2009 at 21:32:24 :
It has an intake in the base of the wall in the hall over the garage. It drops directly into one of the joist runs in the garage ceiling (which had no insulation at all). From there it goes back into the house using the joist run then turns 90 degrees and goes 3 feet to the furnace. The cold air return for the 1st floor is at the 90 degree bend.
What I did was box in a portion of the joist run from the hall intake to where it enters the house. About 5 ft. I put 2x2 runners along the joists and then boxed it bottom and end with 1/2 plywood. Then I put 4" of foam (aluminum foil skinned) over the boxed area and then sheet rocked over that. The real kicker is that there are heat ducts hung from the joists in the garage. They were boxed with sheet rock. There was no sheet rock between the heat ducts and the joists so all joist runs were open to the boxed in heat ducts. Obviously the cold air return was also open to the boxed heat ducts. That made every joist run wide open to the cold air return and the uninsulated walls at then end of the heat ducts. Only the top 3 1/3 inches of each joist run had insulation which left the bottom 6" insulated only by the sheet rock. So the cold air return was sucking air from the bottom 6" uninsulated joist runs as none were very well sealed as shown buy all the dust in the joist runs. The cold air return was sucking basically only cold air from the unheated and uninsulated garage. That is also the source of the cold draft in the hall. Now the cold air return only sucks air from the hall and the 1st floor's return as it is a sealed and insulated. I can really feel the air being sucked into the intake in the hall now.