Sound deadening insulation

I have some foil sided felt sound insulation that the instructions say to mount with the foil side facing the noise/heat. My builder experience says to put the foil side to the heated side.

In my cab roof and floor, which way should the foil face? It's not peel and stick so I can take the best 2 out of 3 recommendations or flip a coin . Thanks

 

Insulation

Larry, under the dash in my Olds, the side with the backing faces outward and the "soft" side is glued to the metal underdash/firewall. I have some spray adhesive I bought at KC that works great if you want to use it. There is plenty left in the can.

Bob

 

The insulation is installed so the foil side faces to the _outside_ of the veihcle.....

 

As said by the last post if your trying to keep heat out.