You want the dynamat to be the same temp as the car. you can use a heat gun but you run the chance of the backing coming off. I would just lay it on the roof of the car in the sun for a few min it will heat up enough. Most people run in to the problem of it not sticking cause they put it on when the metal is to cold, if it sticks it'll come of shortly after cause it wont bond right, not to mention all the condensation traped under it. Thats what gets most people.