There are two kinds of film - one with water based adhesive, that kind can be removed with warm water, worst case with a steam cleaner. If a solvent based adhesive film was used, then that kind can be removed with a citrus based cleaner, diluted per label instructions.
I'm not sure dry heat alone is going to release either kind of adhesive and even if it lets you get the film off you'll have adhesive residue left that will make it difficult to keep the carpet from attracting a lot of dirt and debris.
Be careful if you go the heat gun route - it can output heated air at temp of 1000 to 1400 degrees F. Some kinds of carpet will melt at temps as low as 200 - 300 F !
Randy - Manhattan, Kansas
2015 Vista 27N
2016 Honda HR-V