Intake and exhaust question 9'x11'x7 1/2' room

Can I have a 12" 1200 cfm fan for exhaust and have a 6" 440 cfm fan for the intake. I need to have an active intake so I can pull fresh cold air from out side ( it's pretty cold at night here where I live )to cool my 4200 watt bare bulb vert setup. I also have a 3"x 9" opening without a fan to let air suck in when the 6" fan isn't running.

Thatll work fine. depending on your room size the fan exhausting might have enough power to pull alot of air in but its always good to have a little extra especially with that much wattage

My room size is in the title 9'x 11' x 7 1/2'. Thanks for the input I just wasn't sure if the intake was enough. I plan on having the 6" intake fan connected to a plug in thermostat so when the room is cooled to 74* it will shut off , but the exhaust will still be running. That's why I figured I would leave the 3" x 9" opening

You should be good either way. Id try to make a rough filter for that 3x9 opening just to ward off any pests seeking warmth as temps drop.

Also with that 3x9 opening wont that allow light in (that you don't want) when it comes time to flip to 12/12? You will have to incorporate some kind of light shield.

With that opening and the 6in intake fan you should definitely have enough flow to supply the 12 in exhaust fan.

Is that a12in fan connected to a carbon filter? Just trying to picture your setup

Mr John said:

Also with that 3x9 opening wont that allow light in (that you don't want) when it comes time to flip to 12/12? You will have to incorporate some kind of light shield.

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something like a Louvered Vent, if you find the right dimensions, works well with s a passive intake. (im planning on using that one in my set up) good luck!

Trippy.

I'm not worried about light leaking in. It's pitch balck on that side in the room . I have a hepa filter I cut and put into the 3x9 space. No carbon filter connected to the 12" exhaust. I have another 6" inline fan with a filter constantly scrubbin the room

Purpsdro420 said:

I'm not worried about light leaking in. It's pitch balck on that side in the room . I have a hepa filter I cut and put into the 3x9 space. No carbon filter connected to the 12" exhaust. I have another 6" inline fan with a filter constantly scrubbin the room

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You need a carbon filter on exhaust no questions. My room 7x12x9 I have a 8x39 inch phresh filter with 745 cfm hamging from ceiling,, a 6x24 phresh filter with 470 cfm hanging from ceiling, I also have a 8x24 for exhaust phresh filter and everything is new I buy all new filters every year and if I exhaust my room at night with no filter on exhaust there is still enough smell that it smelld like ur neighbor is burning a fatty so filters are key you could also try a ozone generator on exhausr side for smell purposes but its a must for stealth

I'm not worried about smell . Everything I'm doing Is 100 % state legal. I only have 7 plants.and the smaller fan and filter does a great job at removing the smell. And beside my whole upstairs smells like weed anyways from me an my girl smoking all the time

Once I have some free time I plan on building th large diy trash can carbon filter

I bought duct damperd and they open and close by 110volt. I got it from smarthome.com they have normally closed and normally open damper. Put it on a timer and allow it to open for a few and once timer kicms off it automatically closes off to reseal room

Thats a lot of air movement. Do you exhaust directly outside? If you do your more of a man than me.