I had a strange Idea today, what if i get a piece of tubing put one end in the closet where Im growing near the light and put the other end outside attached to one of those rechargeable portable blowers for air mattresses to the end. I think his is a pretty interesting Idea, but it only works while its still cold outside, you could probably do it during the summer substituting your airconditioned room for the outside. Side note: you should also have a fan in the room where youre growing to circulate the air. Plus those air pumps are sort of noisy but you could run it afew minutes a few times a day. As for a good operating temp, id just be simple and say that if the room feels like its a 300 degree oven then its probably too hot, and needs some sort of cooling apparatus.