They have done much of their testing in las vegas and phoenix where conditions are the worst and 150 degree attic temperatures are common.
Attic is over 125 degrees.
To avoid rotting wood clumping insulation and mold your attic needs to be properly ventilated.
How to check attic ventilation.
In a standard attic with soffits and ridge vent the air s really not moving much.
An overheated attic can bake asphalt shingles on the roof and cause them to deteriorate.
Some attics i ve worked in topped 140 ish.
Ideal attic temperatures shouldn t be more than 10 to 20 degrees hotter than outside temperatures.
The sweat runs off you in rivers.
Get to the middle of those ridiculous hot days and the temperature inside the attic could easily top out at 125 degrees f or even higher.
An unventilated attic can reach 150 degrees in the heat of summer 50 degrees higher than it should be.
Moreover if you have asphalt shingles on the roof attic.
If it s 90 degrees outside the attic temperatures shouldn t exceed 110 according to home inspector jamison brown of amerispec home inspection services in poquoson.