So it’s currently 100 degrees F in my garage today. I’m sure it will only get worse as the summer goes on. I added some of those insulated garage door panels, but I don’t think they did anything.
Now I’m wondering if I should add fiberglass insulation to the attic space above the garage. Would this help, or just lock in the heat? Would using a radiant barrier up there work better?
I did a radiant barrier on my rafters to guide heat up from the soffits to the ridge vent and then insulated the joists. Blown in insulation is pretty cheap. While doing other work I also insulated my southern facing garage wall and of course insulated the garage door (and sealed the edges). This made a noticeable difference in the temperature of the garage. I can turn a couple of fans on in the garage and leave the door to the house open and achieve a very reasonable temperature in the garage if I plan on being in there for a length of time. This helps in both summer and winter.
Put in a radiant barrier. A radiant barrier is a layer of metallic foil that reflects up to 96% of radiant heat, assisting in the energy performance of a building.
If you can cool the garage, insulating the ceiling will help. Even if you run a fan to pull in cool air at night and then try to hold it in, it’ll help.