My old G-O got taken down, and all the equipment is gone. I have always used cfl's for veg, and 1000 watt water cooled HPS for flower. So I have no experience with air cooled. I am starting up a new G-O in the next few weeks. I won't be able to cut through ceilings or walls to move air outside of the grow rooms. So this will be a closed room system. I was thinking about going with T5's for veg, and water cooled again for flower, but before I buy that expensive water cooled equipment thought I would check out how air cooled works. If I can't pump air out of the room can you still use air cooled lights efficiently? Where exactly does an air cooled light get rid of the hot air? I have always assumed it has to be circulated outside the grow area. If this is the case then I will have to go with water cooled again. I like water cooled, but they are expensive so I am just checking on possible options. How does the air cooled systems operate? Thanks.