Fan size?

Discussion in 'First Time Marijuana Growers' started by Bignuts44, Oct 25, 2006.

  1. I have a basement thats 8x8x6ft tall. I only plan on usind a 2x4x6 sized area for growing. Do I need a exhaust fan large enough for the whole room or just the growing area? I plan on using a 400watt hps. Thanx in advance for any advice.:D
     
  2. I suspect it would be a good idea to get an exhaust big enough for the whole room, that way you are cycling all the air out of the room and providing plenty of fresh CO2 into the grow room. However, a larger grow space will allow more CO2 into the grow chamber so theoretically if you have a powerful internal fan you could get away with the smaller exhaust. Does that make sense?
     
  3. So what size of exhaust fan should I get? The basement has access to fresh air so I thought I wold not need a intake fan. I figured the exhaust would suck old air out and draw fresh air in, right.
     
  4. The chamber is 384 cubic feet in size, so you want an exaust that can replace that much air every five mins. Look up fan sizes and see how much air they can push out, which is usually given in cubic centemeters per minute, and then you need to multiply the the ccpm by 5 (do the conversion from cm to ft) and you have the result.
     
  5. So then a 170cfm fan should work? I was looking at the eco plus 4 inch inline fan. Just wondering if anyone knows how loud they are? It says in the ad that they are much, much quieter than other fans.
     
  6. Ummm...some confusion here. If you multiply the cfm by 5 then that is replacing the air five times a minute, not once every five minutes.

    The benchmark I've always heard is a factor of 3 not 5, though going bigger won't hurt. So...if you have a 25 cu ft grow space you want at least a 75cfm fan.
     

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