Air circulation question

aram

aram

Member
How big an exhaust fan do I need for a 35 cubic foot closet in terms of CFM? Is 80 CFM too little? I can get a 250 CFM for only 10$ more but I'm afraid it'll suck out all the humidity too. I'm gonna be using a 200 watt CFL and a bunch of low watt CFL's so I dont think I should be too worried about heat but I still want good air circulation in there.

Thanks!
 
ppkk

ppkk

Member
hopefully noone will be mad at me ;D
i dont think my quest. is important enough to make a new topic so i`ll just jump in this one with my question.
so... take a look, is this the best way for 3 vent system??

theyre pumpng and sucking the air well, the only problem is - i cant think out where to put them((
i can use only these 3 vents.
tnq !!
i really cant decide.. just say yes, and i`ll be happy with it :)
 
d.c. beard

d.c. beard

Well-Known Member
I would move the right-side IN to a lower location like the left-side IN.

And regarding the fan situation...I would get the highest CFM fan that you can afford, and then, coupled with the fan-speed controller that you're going to need to buy you'll be able to dial-in whatever specific speed you want. So go big so you don't have to replace it later cause you went too small initially!
 
aram

aram

Member
ppkk said:
hopefully noone will be mad at me ;D
i dont think my quest. is important enough to make a new topic so i`ll just jump in this one with my question.
so... take a look, is this the best way for 3 vent system??

theyre pumpng and sucking the air well, the only problem is - i cant think out where to put them((
i can use only these 3 vents.
tnq !!
i really cant decide.. just say yes, and i`ll be happy with it :)
Click to expand...
i've been told that exhaust is more important than intake cs when you create negative pressure in your grow box, air will eventually come in from any openings you have. i'd use two fans as an exhaust, one on each top corner and use one intake at the bottom.
 
Shanus

Shanus

Active Member
I would suggest getting on Ebay and buying some cheap computer fans. 120mm is decent size. If your room is only 35ft and the fan is 50cfm, then you'll be evacuating the room more than once a minute. with just one cpu fan going (passive intake) you won't keep smell or humidity in that closet. If you are using a filter, I'd suggest 2 exhaust fans (w/filter), one pulling, other pushing, at top. I used tiny cpu fans for my seedlings and to keep my compact tubes cool. Hard to create a breeze and not a hurricane, in tiny closets. Once I moved to hps, the game changed. Hope any of this helps. Best of luck to ya
 

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Guyute7

Guyute7

Active Member
I agree w Shanus. Cut down on the noise if you can and a pc fan will do the trick for your size area. and as far as the 2 intakes they probably should both be low and the exhaust where it is but if your lamps are anything more than fluoros you are going to need a much better exhaust fan than that. those boosters don't do much, they are meant to help an exhaust that is moving air a long distance rather than doing all the work. passive intake is good if exhaust is capable of moving enough air
 
aram

aram

Member
i honestly think pc fans are too small for my set up and wont be enough to bring down the temperature (i'm gonna have at least 400 watts worth of CFLs in there) i think i'm gonna go with a 200 CFM fan and hook it up to a thermostat set at 75F.
 
vh13

vh13

Well-Known Member
aram said:
i honestly think pc fans are too small for my set up and wont be enough to bring down the temperature (i'm gonna have at least 400 watts worth of CFLs in there) i think i'm gonna go with a 200 CFM fan and hook it up to a thermostat set at 75F.
Click to expand...
I'm working with about 350 watts of CFL in my flowering room right now and two 120mm PC fans powered at full voltage have worked quite well. They don't pull through carbon filters well though, but if you plan to scrub the air centrifugal fans pull through scrubbers really well.
 
d.c. beard

d.c. beard

Well-Known Member
FYI I started out with pc fans and ditched them not only because of their weakness, but mostly because of the loud noise they make. My 8" inline fan makes about half as much noise as a 6" pc fan.
 
aram

aram

Member
yeh but for that price i dont really care lol plus the fan will run mostly during the day when i wont be home so a little noise wont bother me. i've decided to go with the 6". should be more than enough for the closet i'm planning on converting into a grow room: cloning under T5s, mother in DWC, veg area (Drip)
 
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