[quote=CafeMoto]I nominate this thread to the vault of 2011 classics! [/quote]

Except the thread is from 2010.

Per your question, I have found that in San Diego, a triple layer door (insulation as the center layer) does not help keep heat out.

In my last two homes, I’ve had west-facing garage doors. I put triple layer doors in my last house and I think the garage actually got hotter. My theory is that it helped hold the heat from the car engines in, though I can’t prove it. My current garage has a single layer door and it seems to me the garage stays cooler than my last home…with similar color garage doors.