example...
I have a 315 cmh In a 3x3x7 tent and a 630 de cmh in a 5x5x7. both tents are in a bedroom in a home with central air.
cmh lights are as hot as hid in the first place. hid lamps turn 60% of the electric into heat and 40% into light. cmh its 50%50% anywho a little 40 cfm booster fan on top of the tent pulling out heat. fresh air enters bottom flaps room stays 70-75 so does the tent. same for the 5x5 except its a 6 in inline fan and filter pulling out heat. now if it was a 600 watt hps it would require an air cooled fixture.... unless its in a basement most basements stay around 64. your fan and filter alone would probably be enough in that case