Q. I live in a condo with an attached garage. The current garage door insulation is rated at R-4. Even with that it’s cold in the winter and hot as Hades in the summer. Local companies have given me estimates to increase the insulation by installing a new door. This would cost over $1,000. I’ve seen kits that allow you to add insulation to the inside of the door for one-tenth the cost of a new door. Are they worth the price? Will the kit last? Will it fall off the door onto my new car when the door in in the up position? What would you do?
A. I know all about cold and hot garages. My current home has a large three-car garage that’s attached to the house with a small connector hallway. My previous home had a very large garage that was 95 percent detached from my home. Even though the walls and ceilings of both are insulated, they still aren’t comfortable when the temperatures get extreme.
I think many people expect too much from insulation. Based on the constant flow of emails I get, it seems that many feel if something is insulated, then that means the space will be comfortable almost all the time.
What you, and others, need to know about insulation is that it simply slows the transfer of heat. Heat wants to travel rapidly from where it’s hot to where it’s cold. This is one of the simple laws of thermodynamics you may have studied in high school physics.
The rate of heat transfer is the R number you referenced. The higher that number, the better the…