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Exhaust vent help... 100cfm enough?


New Member
Whats up fellas, I have a 3'x2'x1'6'' box and just installed a 100cfm inline exhaust fan.. I feel like it isn't much really, I tried to cover up the air leaks as best I could(there are a lot) and I just couldn't feel the negative pressure. I need the pressure for when I get a carbon filter, so I'm thinking I need to go up in CFM anyway.

Heres a shot

Check out my grow journal too - I feel I'm off to a great first start!

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I'm thinking of getting an elbow to connect to the exhaust guard vent I have put in instead of the straight piece to the ducting. Any suggestions will help much appreciated blaze one up for me! :thanks:


New Member
Hi, did you work out the required fan cfm, length x width x hight <----gives you one room change per minute. You will lose some cfm with filter...leaks....and duct, looking at your picture I hope you don't leave the duct bent over in that u shape, you will lose cfm there. :)
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