I wouldnt worry about that as much as trying to control temps in an attic. I dont care how much exhaust you have if you live in warm climate it will get 150f+ up there. God forbid its even close to that and the light comes on. If you live in cold climate which i guess you dont with no roof insulation it is much easier. You want a steady temp around 75f in your tent. Run exhaust out the back of house by a roof vent. It will look like a dryer venting to a heat sesative camera. If temps in tent are controled and exhasted right you have no problem with being seen. I exhaust mine out a dormer on the roof just looks like attic heat escaping. :rasta: