I am growing for the first time in a pretty small closet (3'x3'x10' vertical) with CFLs. My plants are 2 weeks old right now so the lighting is adequate, but I would like to switch to (or add) a 250 or 400W HPS when I start flowering. Problem is, there is maybe a half inch gap under the door from which air can escape, and I can't make holes in the walls because I am renting this place. Is an oscillating fan enough to cool an HPS bulb in a closed space, or am I going to have to buy some kind of expensive cooling system?
Can you keep the door open? And cool tubes aren't that much more expensive than the light itself. You just need the right reflector, an inline fan, and some ducting.
I guess I could just leave the door open when the lights are on since it only has to be lightproof when the lights are off anyway. I would just have to make sure the cat couldn't get in.