I haven’t done a scientific evaluation on the heat reduction but here’s my seat of the pants opinion....
I live in SW Florida, it’s almost October and it’s still in the lower 90s with high humidity. The summer here is actually the rainy season. I read that the insulation on the roof panels does more to prevent interior condensation than it does to keep temps down and to that I can attest it works great. I also know from experience that metal roof panels get burning hot to the touch down here and this insulation has shielded some of that heat. Also the foam/foil insulation I placed under the osb has to help too. I got an insulated overhead door too because someday I may want to add a split AC system, who knows
I’m out there a lot in 90 degree weather and the simple shade the building offers is nice. But the biggest thing that helps cool it off is opening BOTH overhead doors. (There’s an 8’x8’ roll up in the back corner) this creates a cross breeze that pulls a lot of air through the building
I’m really happy with my new garage. Love it.
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