What size fan for exhaust of cab.

I am lookng to purchase my fan for my grow dresser I built. I will be growing one plant, I was thinking one 4" fan for exhaust would be sufficient. Ill be using CFL so I ont think heat will be a problem, Im more worried about humidity. I also live in a cooler climate(northern us). Any help would be helpful.

how about 3x 120mm pc fans or 2x 250mm pc fans with a 120mm inside the cab to circulate air? you would use the 120mm fans one for exhaust one for intake. what size is the box? how many cfls? how many plants?

the is about 3 feet high x 3 feet wide and a foot deep i will be using up 3-4 100watt and maybe a couple smaller ones once the plant is bigger. Single plant grow. I have one 4" inside for circulation. I like it over the pc fans cause they have plugs already on them. I dont want to do any homemade wiring.

hmm. pc fans would really be the easiest option, with the small amount of space you want to conserve as much as possible you could so some duct work and put a inline fan but thatd be expensive, im sure there is another. let me take a look around and see what i can dig up.

natedogg789 said:

the is about 3 feet high x 3 feet wide and a foot deep i will be using up 3-4 100watt and maybe a couple smaller ones once the plant is bigger. Single plant grow. I have one 4" inside for circulation. I like it over the pc fans cause they have plugs already on them. I dont want to do any homemade wiring.

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Thats going to be a lot of heat for that small space, Two 4" axial fans 55 cfm each blowing in at the bottom with a passive exhaust at the top would turn the air over in the cabinet about 12 times / minute, You can have one fan run all the time and 2nd fan come on with the same timer as lights, that might be enough depending on temp outside of cab.