You cant see heat through a brick wall.Cops see a heat signature by heat escaping the house/building.They cant see heat inside a dwelling.I think this is a common misconception used to sell products(marketing)...Thats why you dont want to have your growroom exhaust blowing outside your house without first cooling it somehow....
Very true manic i exaust to an insulated room in the house i only suck air in never blow it out how ever that is the best smellin room in the house lol