I am unsure how many people would consider it to be cost-effective. People would just tell me to buy a new car.
"A white one?"
"Anything but that!"
I spent about the same amount for my fan fold insulation. It is just enough to (hopefully) put 1/4" on the roof and all four walls.
I did two panels and compared them with the adjacent uninsulated roof sections.
On a 90° day it was worth 3°.
I wish that I could save 8-9° for $55!
