Theproxxx
Member
This is what I use for my grow room-does a great job so far and speed controller makes it easy to adjust flow rate.
Looks good. & I have the option to add a carbon filter in the future if I needed one right?
LED grow. Do i need a exhaust? First grow
- Thread starter Theproxxx
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Looks good. & I have the option to add a carbon filter in the future if I needed one right?
HydroRed
Well-Known Member
You need less than 50cfm for your grow size. Simply put, ANYTHING with a 4" flange rated over 100cfm will be more than sufficient. Anything with a speed control is better. The one GBAUTO linked will be good. If it has a 4" flange on the fan, then you can get any 4" filter at any time and it will fit.
When it comes to in-line fans, carbon filters, ducting, etc. 4", 6", 8", 10" & 12" are all standard sizes. If you work with 8" ducting then you get a carbon filter with 8" flanges, and an in-line fan with 8" flanges and so on.
When it comes to in-line fans, carbon filters, ducting, etc. 4", 6", 8", 10" & 12" are all standard sizes. If you work with 8" ducting then you get a carbon filter with 8" flanges, and an in-line fan with 8" flanges and so on.
Theproxxx
Member
Great reply. So I should purchase that one he linked? Does the speed controller reduce the CFM? I don’t want to put something too strong in the tent if I don’t need it
Kerovan
Well-Known Member
Too strong is subjective. I use a 225cfm fan on my 2x4, it's definitely not too strong. Not saying that you need that much, but for it to be too strong it would have be a helluva lot more powerful than that. 50cfm would be far too little in my opinion. I would say the one linked at amazon is powerful enough, but the price is cheap, I don't know about the quality so I cannot say if it's a good buy or not.
HydroRed
Well-Known Member
The one he linked will be fine. Yes it can be dialed down in cfm/rpms by the speed controller.
50 cfm is more than enough actually if you calculate the math for room size and cfm. To calculate multiply length x width x height of growing area e.g. His room is 2'x4'x5' so 40 cu ft total. Your extraction fan should be able to adequately exchange the air in an indoor garden once every three minutes. Therefore, 40 cubic feet / 3 minutes = 13 CFM. A 50 cfm fan would be more than adequate to do a proper exchange of the room once every 3 min.
Your not likely going to find a in-line fan under 100 cfm though so the overkill will be necessary and thats why you can get them with speed controls. The cfm will be there if/when you need them at the turn of a dial.
GBAUTO
Well-Known Member
Yes, the controller reduces the output a considerable amount. I run it at almost its minimum speed during the winter-this is the first year I'm venting my space so I'll see how she doe as it gets warmer in the spring.
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