smokey- if you vent into your house with that amount of juice, you should be fine. using a passive air intake from the outside to bring in cool air would make it better. my attic has several venting holes to disapate the heat. thats with 2400w. heat build up is what will make your shit glow. . like i said, blowing hot air directly outside is the worst. in your situation, think of it as heating your house in the winter. no problem. keep the doors open to the room your exhausting into, to let the heat move through out your pad. yes. flir is useless in the day. if your weather permits, this is the safest possible route. in barry coopers dvd "never get raided", he has examples of flir on various homes. its a must see. i can not recommend this enough.
boroboro- i watched that whole series DEA on spike. 20k's is a shit load. no way to hide that amount of heat. i even watched that specific episode pictured on your post a few times. if you go back and listen to the commentary, at first they act like its so easy to spot. later, they admit its almost impossible to fly around and find grows. how did they find it? a fucking snitch of course. it was their C.I. (confidential informant).
jeff- yes, the windows look hot in flir at night, like the picture in boroboro post. even in the non grow house. but there is still a slight difference.