i brought some c3 sheet and put it on my front facing wall of my grow room, so if the police use hand held thermal imaging they wont see the heat on my front wall, im venting out into my loft/attic and worried about the heat build up as you get the occasional hellicopter go by. I can put the c3 sheeting in the loft but wont be able to put it everywhere as the space up there is too tight. Any suggestions would be great