exhaust

[C.BEVERLY]

what will happen if your pushing alot of air out with no kind of intakes, the building is sealed pretty good, its 6.5 by 4.0 by 8.5 feet high the exhaust is 250 c.f.p.m. no intakes

[Sinsemilla Jones]

If not enough air comes in around the door, the air will come back in through your fan, decreasing efficiency and putting more strain on the fan's motor.