240 cfm duct fan good with carbon filter?

steveo2grow

steveo2grow

Well-Known Member
so i have a 3 x 3ft x 78" grow tent with 400watt mh/hps setup... i'm only growing 1-2 plants and was wondering if a 240cfm duct fan would be sufficient to suck through carbon filter and pull over bulb (cooling it) and exhaust out.... i've always read about inline fans inline fans inline fans, but wouldn't 240cfm be sufficient enough???
 
The fan i assume you are referring to is a "duct booster" fan correct? If it is the reason so many of us are against them is they have no pressure. The CFM rating is based on being in an open room with no restrictions at all, now try to pull through a filter and a hood then around a corner (there is almost always a corner you can't avoid) you have cut the cfm to about a 1/4 of the rated numbers. Inline fans are much more pressure, that is why they are recommended, you can look into pressure of a lot of fans by looking at the inches of water column they produce, some sites will rate this, some won't. Although it would probably completely deflate your tent, i have found a good deal on an 8" ventilator from harbor freight, couple of reducers from home depot and you have a fan that is rated at like 1500 cfm for less than $100, not the greatest on pressure either, but a lot better than the duct booster fans.
 
sounds good... well, i might just leave the filter out of it and use the fan for cooling the bulb since i'm so early in veg... and then when she(s) start kickin' up the smell, i'll get a good inline...
 
good call to not use it. you would have been dissapointed. i use the 6in 250 booster fan for my intakes and a buddy cools a 600 in a 3x3 and a 190cfm fan and filter for smell. when you do go to buy a fan and filter make sure you spent the extra money on a quiet fan if the tent is near you( im regreting this one)
 
TruenoAE86coupe said:
The fan i assume you are referring to is a "duct booster" fan correct? If it is the reason so many of us are against them is they have no pressure. The CFM rating is based on being in an open room with no restrictions at all, now try to pull through a filter and a hood then around a corner (there is almost always a corner you can't avoid) you have cut the cfm to about a 1/4 of the rated numbers. Inline fans are much more pressure, that is why they are recommended, you can look into pressure of a lot of fans by looking at the inches of water column they produce, some sites will rate this, some won't. Although it would probably completely deflate your tent, i have found a good deal on an 8" ventilator from harbor freight, couple of reducers from home depot and you have a fan that is rated at like 1500 cfm for less than $100, not the greatest on pressure either, but a lot better than the duct booster fans.
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i was looking that those harbor freight fans too but thought they were going to be too loud do you run one whats the db on it
 
Duct booster fans work but like he says they don't pull very well at all through a filter. Try garage sales and craigslist - I got a 440cfm inline for $30.

Ambient temp matters a bit as well. How much heat are you creating?
 
Somewhere between loud and really loud, i have 2 of them 1 is ducted in and out with insulated ducting and mounted outside the room, can barely hear it in the room, probably because the other one is insulated ducted in but not out and is used as the intake fan for the room, that one is loud!!! But for the price and cfm they are amazing, just plan on insulated ducting in and out, one i have mounted down with rubber feet, the other is just sitting on a shelf held by ducting, both seem pretty quiet on the mounts, just the actual moving of the air is really loud. Pretty low power consumption also, at least for the cfm.
 
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