fan

[captain23]

hello there community.. i was wondering how do i know if i have the right intake fan and if its doing its job?

 

[ilv911]

The proper size fan for a 4x4 grow tent:
Let me give you an example calculation for a 4x4 grow tent, which is a pretty common size among indoor growers:

Most 4x4 tents measure 48in x 48 in x 80 in. So the total volume of air in a 4x4 grow tent is 4ft (length) x 4ft (width) x 6.667ft (height) = 106.67 cubic feet. But that doesn’t mean you need a 106 cfm fan.

When you consider a carbon filter reducing your fan efficiency by 25%, and one 90 degree duct bend reducing another 30%, a fan with 215cfm will get reduced to ~112cfm (200cfm x 0.7 x 0.75).

So for a 4x4 grow tent with an area of ~106 cubic feet, a grow tent fan (inline fan) rated for ~215cfm would get the job done

I create my ventilation according to this . Used google to find it its not mine

 

[oldfogey8]

I think I remember reading somewhere that shooting for air exchange of 3 times per minute is a good target. Getting a fan larger than you need isn’t a bad idea as well since you can always get a rheostat to adjust the speed lower if desired or needed. If your tent gets really hot, moving air out quickly helps cool the tent down.

 

[pute]

To stoned to figure the math now but I have always ran my fans at 2 x per minute. Less noise.

 

[captain23]

The proper size fan for a 4x4 grow tent:
Let me give you an example calculation for a 4x4 grow tent, which is a pretty common size among indoor growers:

Most 4x4 tents measure 48in x 48 in x 80 in. So the total volume of air in a 4x4 grow tent is 4ft (length) x 4ft (width) x 6.667ft (height) = 106.67 cubic feet. But that doesn’t mean you need a 106 cfm fan.

When you consider a carbon filter reducing your fan efficiency by 25%, and one 90 degree duct bend reducing another 30%, a fan with 215cfm will get reduced to ~112cfm (200cfm x 0.7 x 0.75).

So for a 4x4 grow tent with an area of ~106 cubic feet, a grow tent fan (inline fan) rated for ~215cfm would get the job done

I create my ventilation according to this . Used google to find it its not mine

sounds good,,but what im trying to understand is what do i look for to make sure its doing its job?

 

[oldfogey8]

At a minimum, you want negative pressure inside your tent. You can tell that if you see the walls of the tent ‘suck in’ when you turn the exhaust fan on. The calculations ilv goes thru are a hood guideline I think. Volume of your grow area(if you are not using a tent) is pretty easy to calculate(L x W x H). That is the cubic feet you want to draw out. CFM is cubic feet per minute so buy a fan that will move 2-3 times the volume of your tent or grow space. As I said earlier, getting a fan that has a higher CFM rating is better since you can slow the fan down if needed. There are companies that make fans with controllers that will adjust the speed based on temperature and/or humidity to maintain the desired environment. If you are concerned about noise(exhaust fans are notoriously loud), look for a lower dB rating.

 

[captain23]

At a minimum, you want negative pressure inside your tent. You can tell that if you see the walls of the tent ‘suck in’ when you turn the exhaust fan on. The calculations ilv goes thru are a hood guideline I think. Volume of your grow area(if you are not using a tent) is pretty easy to calculate(L x W x H). That is the cubic feet you want to draw out. CFM is cubic feet per minute so buy a fan that will move 2-3 times the volume of your tent or grow space. As I said earlier, getting a fan that has a higher CFM rating is better since you can slow the fan down if needed. There are companies that make fans with controllers that will adjust the speed based on temperature and/or humidity to maintain the desired environment. If you are concerned about noise(exhaust fans are notoriously loud), look for a lower dB rating.

nice thx so much i think i got it now, and i deff think the fan that came with the tent isnt going to do it cuz its only 76cfm and my tent is 4x2x77'' so yea ima just order a bigger one like you said tht also has tht controller.. cool thx for ur help., appreciated #420