Ventilation Question

ok i want my intAKE TO PULL AIR FROM THE GARAGE and exhuast into attic,,,anything wrong with pullin air from garage also...8x4x8 grow space 11x9x8 sized room 6"intake 207cfm and 6"exhaust/car 400cfm..2 1000w 6"aircooled hoods...any advice plz

start her up n check your temps...good growin...peace

would there be any disadvantages from pullin air from the garage instead of directly from outside? also u think the cfm are enough on both in and ex...if not so i can upgrade

Its always easier to pull air then push it. Double up on exhaust and just cut a hole for passive intake. Check the air quality in the garage. I've head of people growing outside and taking their plants inside to their garage for night and suffering from bud rot. Make sure the humidity doesn't get too high in there and make sure the garage is receiving air from outside. Might just be easier to pull from outside but I dont know you layout.

dont run any motors in the garage.

how is the air in the garage? you want a passive intake. You want to create a vacuum in the grow room. Stick a carbon scubber on the exhaust

I have simular size space and lights.

400 cfm is enough to vent the room, but not really enough to cool the room when mother nature is not cooperating. I think you should get a LARGE 8" fan and run it off a temperature sensitive speed-controller. That way, you can run the fan at idle speed during normal operation but you'll have plenty of horsepower available to keep your room cool under any circumstances.

http://aeroponicsnmore.com/climate-control-ventilation-c-23_5/temp-2v-fan-speed-control-variable-idle-setpoint-p-181

I'd hold off on intake for now. The fan will suck as much air as it needs so there is no need to help it unless you've got a great source of cool outside air you want to pipe in. Otherwise, cracks around the garage door will work just fine.

You'll definately need the carbon scrubber (suggest Can-66) or your entire neighborhood will reek.