Airflow for marijuana growroom by opening door

A question from a fellow grower:

i am growing in a small room with the heat blocked off do i still need to exhaust the room a bedroom if only using a 250 to 400 watt hps or mh while exchanging air by opening the door or window periodicaly any help you could give would be appreciated

Yes you can. You still need at least a fan moving the air around. You do not want radiant heat building up over your plants. Even a 250-400 watt lamp can raise temps to the 90’s. This is why we use 2-3 fans and ventilation.