My friend is a nuclear engineer and let me borrow his thermal imaging gun that they inspect reactors with.
I used fatmat, a tar like adhesive material with a layer of aluminum over it for my cab. It did not block the thermal signature but defnitely reduced it. I cant speak for the products that were actually designed for this purpose as i have never used them.
After looking at things around the house with gun though i would agree that onless you are using a room over 10x10 and at least 2 x1000w I dont think it is really worth it. There are so many things around that generate heat. I was looking at mt neighbors houses and shit too.
Probably freaked some people out... good thing they all know im an asshole though and not scum LEO.