I have a walk-in closet setup currently with 8 foot ceilings, and about 6 feet wide by 8 feet long. I have a cooltube reflector and a fan but I am curious where I am going to exhaust the heat. I have grown with this cooltube before, temps were normally 85+ but the plant survived and I have had one harvest, I want to be able to put the light (400w HPS) closer to the plants but the heat is an issue. I have ducting, but no place to put it yet. I have been thinking about cutting a 6" hole in either the ceiling (to the attic) or the wall.....my main question is, what are the problems/consequences of venting into the wall itself? The wall in question is adjacent to an exterior wall on the 2nd story, both of my neighbors in the townhome smoke so smell is not a huge issue, plus there isnt much of one. Should I really cut a hole in the ceiling, is the difference that much? I assumed that the hot air would be blown in to the wall cavity and make its way (as heat rises) up in to the attic itself. I do not have access to a window, and the A/C unit is far away so my closet gets MINIMAL A/C, but there is an AC vent I have debated trying to exhaust out of. I suggest the wall instead of ceiling because the light is very low and the ceiling very high...it would be about 1 foot of ducting to exhaust through the wall, about 6 feet for the ceiling. Can I just exhaust a 400w HPS directly into drywall? BTW I live in Florida and its summer, so the temps in the Attic have got to already be insanely high and humid, its really sticky here sometimes.