Is it just be thats way behind? you can buy Infa Red heat signal blocking film.

Is this new on the market, its been developed by NASA? basically it blocks 97% of heat signals being picked up by our loved police force. If its been around then why in gods names are no shops stocking it!!! £120 for 100mtrs 48" wide. you could do a 2mx2mx2m self build room. Any cheaper places around that stock it? this stuff is a must, you have to be a idiot not to use it if you are aware of the product! i know what im doing very soon.

It's effective in improving the efficiency of pumping heat around through your system. You are still going to have to get that heat outside of your grow area regardless. And the outside is what FLIR sees. Even if (and especially if) you IR film your entire house, you are still going to have to exhaust the heat somewhere...