[DeanFL]

I installed same in our garage a week ago. Ours faces direct east and that morning sun... yikes-could cook an egg on the inside of the door metal at 11am. Tried, but the egg kept sliding down.. I jest.

The radiant barrier (only about 1/4" thick) is double sided foil with air bubble plastic in between. I did not use the tape to adhere, was afraid it would unstick in the heat. And I bought a pack of 3/4" thick styrofoam panels at HD. Sliced them into 2" wide panels and constructive adhesive to each section of the inside door. Then cut the barrier to fit each area and construction-adhesived all over the styro and adhered the barrier to door sections. So now there is a 3/4" air pocket between the metal door and barrier. Had to jockey around the garage door windows (already covered in glass film).
DEFINITELY not as steamy in the garage now even at 12noon - I should have temped before/after, but... Whole job with styro, barrier and constuct adhesive tubes, about $110. SO worth it - and the door is very quiet open/close. Looks clean inside too.
Now we need to cook eggs in the kitchen...