Hey subcool,
thanks for all the great info. I have been stumped for weeks on what to do about my ventilation situation. About six posts back Jack45 mentions a situation similar to mine, but no one really answered his question besides blakbotany mentioning something about CEA (which i will have to look up). I have a small 6x2x7 closet that has double doors that i could leave open. The closet is inside an approximately 15 x 18 foot room with a single window and door. The window is right in the front of the house in plain view. Can I effectively cool the closet (single 400 watt HPS/MH) by leaving the doors open and circulating air out of the closet and around the room (this is what i prefer to do-it seems easy and inexpensive)? I can also open that room door to supply fresh air as needed, since stealth might only be essential when i have an occasional guest. It is very hot outside the house and can be quite cold in winter. I could cut holes in the roof of the closet for intake and exhaust from the attic above, but that air is really hot already and I'm concerned with mold. I've thought out these scenarios, but I'm just not sure what to do. Could you please advise me?