Computer fan to exhaust veg chamber?

Hello everybody,

I have a 4x4x7 tent with an aircooled 400w mh light.

I need to incorporate an exhaust for some ventilation. Right now there is a oscillating tower fan in there but I would like additional air. I was thinking of using a computer fan to exhaust the room but I only really see people using computer fans for microgrows, not small tents. Why not???

If my calculations are correct, then my room is 4x4x7=112ft3 total. According to the stickies, if I want to only replenish CO2 then I need something that will remove that air once every 3-5 minutes... or a fan that will move 37cfm to 22 cfm. So could I just get a 40cfm computer fan to exhaust and be fine?

I was thinking of getting either this 4 inch axil fan that moves 100cfm: http://www.bustan.ca/product_detail.asp?menuID=1&SID=13&PID=897

or this computer fan that moves 110cfm but is on a variable speed controller so i could reduce the speed when needed:http://www.newegg.com/Product/Product.aspx?Item=N82E16811999344



One other thing to note, I am drawn to computer fans because they are so quite. My grow tent is directly underneath my porch. I tried an inline fan but it was just too loud and conspicuous.

Any feedback is appreciated!!!!

can anybody tell me whether this is a good idea or not???

If you want it for just ventilation, not cooling, then you should be good. Many grows combine cooling with ventilation, in which case a computer fan would not be enough.

yo! i have the same tent. my 400w hps is in a cooltube with duct going up and out and this http://cgi.ebay.com.au/NEW-HYDROPONICS-6-VENTILATING-DUCT-INLINE-EXHAUST-FAN_W0QQitemZ320381860277QQcmdZViewItemQQptZAU_Seed_Starting_Hydroponics?hash=item4a983f39b5&_trksid=p3286.c0.m14&_trkparms=65%3A1%7C66%3A2%7C39%3A1%7C240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50
sucking the air outa the tent thru the light and away for good. these fans are very quiet, super sucky and all that shit.

i had 3 pc fans on my last cabinet and the noise was incredible. splash out and get something like this as u won't regret it later when the pc fans start to get dusty and crap.
oh and my temps sit around 24c constantly so far but am yet to see what summer will do when normal air temp is 30c-ish. anyways good luck

thanks for the feedback!

yes, i will be using it just for ventilation.

planetfonz... the pc fans were really noisy? i was initially drawn to them because of how quiet i thought they were. like i said my tent is directly underneath my porch so i need something that is really quite.

i like that fan but i don't need one quite that powerful. maybe i will downgrade to a lower cfm.

yeah i found the pc fans went at a higher rpm, and created more of an audible noise when i stood near it .. then when they would accumulate dust the noise would begin increasing ... food for thought anyways

makes sense... maybe i will get a stronger pc fan and put it on a variable speed controller

anybody have any recommendations on PC fans they have used?

Check these guys out, http://www.acousticpc.com/
I used 2 of these in my custom pc......I cant speak for growing but I can speak for proformance