You must not be very observant. Don't you see all those white dots on the roof? If you watch they all become more evident as they zoom in. Those are the heat signatures of the things in his house like 60W light bulbs. What do you think a 1000W HID looks like when they focus in.
Thanks for the feedback, but not here to cast insults with anyone.
I still just don't see any internal lights in the video and I re-watched. In any case, there's just no way a 60w bulb puts out enough visible or IR radiation to be detectable from the outside (FLIR or not) through induction and convection layers of air, roof shingles, tar paper, plywood, carpet, furniture, air conditioning, insulation, and anything else that heat might have to travel through to get to an external wall/roof where it could be absorbed and re-radiated again? 60w wouldn't hardly even make it through a single piece of plywood placed two inches away from it, and wouldn't have a chance of making it through a piece of plywood at all that's placed more than a few inches away. You can try the experiment yourself in a limited sense by just feeling if any heat from the light is making it through to the other side. IR just doesn't penetrate any distance/material very well.
Are we maybe seeing the bathroom/kitchen exhaust pipes on the roof instead?
Look at this video.
http://www.youtube.com/watch?v=KVespTKFXMI&feature=related
Besides, there is no point in arguing about it. People have and do get busted due in part to the ability to see the heat signature of the grow lights. It's not heat coming from a room. If that were the case everyone with a fireplace, wood burning stove, space heater or window AC unit would be suspect. Trust me, they can see HIDs through your roof.
Didn't see anything unexpected in that video. People walking outside and the side of a building; was there something you were trying to point out specifically? And no, not everyone would be suspect - only those that stand out crazily from the surrounding houses by unusually high amounts of radiating heat. And there was an article someone just the other day about the police in the UK serving a no-knock warrant based on the presence of heat coming from an attached shed to someone's home... turned out it was just a wood-burning stove. Kind of just goes to show that FLIR can't determine what specific heat sources might be - only that there may be an unusual amount of heat present compared to surrounding houses/roofs.