Car windscreen actually are made from aluminum film (metalised foil) which is actually made of plastic and it looks like silver in colour. In order to determine whether it is made from plastic or pure aluminum, you can use a lighter and burn the aluminum top and bottom portion. If it melts and the fire spread, it is actually made from plastic which is durable when you need to do repeated folding of the material.

PU Foam attached with metal roof actually can help you in sound reduction but if you are looking for something more on heat insulation, aluminum foil will still be the best option. This is because the PU foam tends to become powderise and drop down when the bottom supporting part give way. If you wish have a better longer lasting try use those which is bottom part made of steel instead of plastic. But whenever you choose to cut out the heat, you need to look at the product spec such as thermal resistance which is higher the better and thermal conductivity, the lower the better it perform.