I was having the same problem.

Check out what I did, no permanent changes to the original structure at all. (once you put the door back on of course, simple enough though...) If I open the windows at night, letting the cool night air in, then close them up before the temp starts to raise in the morning, I never even have to touch the A/C. On an 85 degree day, the closet didn't raise above 80 with fans on, no A/C all day.
norkali Reviewed by norkali on . Reducing Closet Temperature We have 2 plants going in a closet under a 400w HPS. They are currently 4 days into flower, and were grown outdoors in the vegetative stage. There is mylar on each side of the walls, and a fan blowing from the floor up on to the plants. The temperate on the thermometer is at 100d F, give or take a small amount. I would like to reduce the temperate to about 85d F, but I cant put holes in any walls ruling out using an extractor or something like that. I have the cupboard door open about half Rating: 5