Attached Garage and Conditioned Room Temp Fluctuations
I’m in a newly constructed house by a decent tract builder near Atlanta (zone 3). My master bedroom is at the back of the house on the second floor. In front of our bedroom is our master closet which abuts the uninsulated garage attic (that wall is insulated and sheathed with OSB on the garage side). We also have a large storage area in the garage that goes under a portion of our closet and bedroom (there is insulation in the joist space between the garage ceiling and our bedroom/closet floor). Prior to building, I was concerned about temperature issues with my room being partly over the garage but was assured that it would be sealed and insulated well and wouldn’t be a problem. It’s a problem, but one the builder won’t take care of (because on the really mild day they checked, there was less than a four-degree difference between rooms upstairs). So I’m looking at various ways I can improve my room’s comfort and reduce the temperature swings. I believe the most influential changes I can make at a reasonable cost are to insulate the garage to some extent since that affects our closet wall and our floor. I’ve insulated the 2-wide garage door with a radiant barrier bubble wrap style insulation. So far, I don’t think that will do much because the ceiling in the garage isn’t insulated. So I’ve had a few thoughts and I’m not totally sure which way to go. I’ve thought about using the radiant barrier bubble wrap on the underside of the garage rafters to reduce the summer heat gain in the garage (and to a lesser extent keep in some heat in the winter). I’ve also thought about using that radiant barrier bubble wrap or some other type of insulation on the attic side of our closet wall, but that won’t help with the floor/garage ceiling. Obviously, I could also insulate the ceiling with batts, but I feel like that will help more in our short winter than in our long, hot, summer.
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