Fresh Air 6x6x7.5

TomWolves

Member
Hello All. I'm a first time grower, I am building a 6x6x7.5 feet grow room in our basement. My question is, will a 4" inline fan bring in enough fresh air for the girls? I will have a 6" exhaust with carbon filter. It is 270 Cubic feet. Thank you for your knowledge Have a great day to all!
 

Renfro

Well-Known Member
How many CFm is the fan rated for? You want about 800 CFM for that size room. You are probably looking at an 8" blower minimum.
 

TomWolves

Member
How many CFm is the fan rated for? You want about 800 CFM for that size room. You are probably looking at an 8" blower minimum.
The 4 inch fan is rated 190 CFM, but this 4inch fan I want to use just for intake fresh air. Then I was planning on using a 6 inch exhaust with 450 CFM, with my calculation I have 270 cubic feet of space , so 6x6=36x7.5' = 270 I WANT THE AIR TO CIRCULATE 6X'S AN HOUR SO I MULTIPLIDE 270X6=1620 DIVIDE 1620 BY 60 I GET 27 CFM, WHICH I BELIEVE IS ACUTALLY 270 CFM'S. HOW DID YOU COME UP WITH 800CFM RENFRO? My math is probably wrong, but this is what I'm trying to figure out. Sorry!, my caps lock was on. Anyhow thank you for your input Renfro.
 

Renfro

Well-Known Member
I did my math based on wanting to exchange air 3x a minute, thats for cooling. If that fan isn't cooling then it will be fine. I would use the 6" exhaust fan to pull air thru the hood and use a passive intake. You wouldn't need the other fan.
 

Bookush34

Well-Known Member
i have a 4" fan for my 3x3 tent . its turned all the way down on a speed controler.
plenty of air flow for me.

i bet a 6" would be losts for a 6x6 area
 

TomWolves

Member
I did my math based on wanting to exchange air 3x a minute, thats for cooling. If that fan isn't cooling then it will be fine. I would use the 6" exhaust fan to pull air thru the hood and use a passive intake. You wouldn't need the other fan.
Renfro, what is a "Passive Intake"? Thanks !!
 

Renfro

Well-Known Member
It's just a hole that air can flow in to equalize the pressure as air is being blown out a different hole using a blower. The intakes are usually low (cooler air) and the exhaust is usually high (hotter air). You want a passive intake area of at least 2x the area of the active exhaust.
 

TomWolves

Member
It's just a hole that air can flow in to equalize the pressure as air is being blown out a different hole using a blower. The intakes are usually low (cooler air) and the exhaust is usually high (hotter air). You want a passive intake area of at least 2x the area of the active exhaust.
Thank you Renfro, have a good one.
 
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