Insulate existing garage walls?
I have a house in Houston with drywall already installed on all 4 walls of a 2-car 22’*25′ garage. Two walls are shared with conditioned space and insulated. One SW facing wall has no insulation, and the NW facing wall is 90% insulated garage door, the remainder uninsulated.
The uninsulated SW wall (afternoon Texas sun) actually protrudes into the conditioned house, so only about 15′ are uninsulated. The garage ceiling is not currently insulated.
My goal is to make the garage a little cooler in the summer and a little warmer in the winter. I do not plan to add HVAC.
Adding insulation to the ceiling is obvious, the garage gets a lot of heat from the unconditioned attic through the uninsulated ceiling in the summer.
My question: is it worth tearing out the 15′ of drywall on the SW wall and insulating?. How much temp difference will it make inside the garage to insulate the 15′ of SW facing wall? Will it be a 1 degree difference, or a 5 degree difference?
I will do the work myself, and estimate about 2-3 days and a few hundred dollars to tear out the drywall, insulate, replace drywall and mud,.. Not a big cost or time sink, but if I’m only going to get 1-2 degrees of change in garage temp it probably isn’t worth the effort.
Thanks for considering this,
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