I have a 7 foot by 5 foot closet with a 8 foot ceiling I'm using to grow. I was just wondering how hot a 600 watt HID runs, or how hot it would make the room.
General rule of thumb, if you can hold your hand on top of your plant without burning your, everything will be okay. It's best to air cool all. Keeps temps under control.
HID runs very very hot i would not recommend using it with out an air cooled reflector and adequate ventilation to go along with it.