Ventilation...

I have a grow room 8' x 14' and 8' high. Using 1000 watt hps and bringing in fresh air with an a/c. What size vent fan should I be looking for? How many cfm? Thanks....

Ok heres the deal if you are using ac will not have to vent out any air. All you willhave to do is keep the air circulating with a charcoalcarbon filter within the room. A fan should be able to replenish the rooms air within 5 minutes.

8 x 14 x 8= 896

896 / 449 (lets use this as the recommended CFM fan for your room) = 1.9

So a 449cfm fan will replenish or recirculate the air within a room with 1.9 minutes.

Since you have acin the room I suggest you get an aircooled reflector to exhaust the heat from outof the room as well.