How many fans to properly vent my flower box

[Ryanobrian]

So my closet is 21"x21"x56" for 171.5 square feet. I have a 150w hps in there for flowering. I was thinking 1 or 2 on the bottom for intake and 1 on top for exhaust

Also could i just use computer fans? What I don't understand is everyone says that the box has to be light tight. How is that possible if there are wholes in he box for computer fans??

 

[ANBU]

read this before you do anything with your fans. it helps
https://www.icmag.com/ic/showthread.php?t=112862

 

[Ryanobrian]

How many fans to properly vent my flower box

So read it and am not really getting it. I have a 14.29 cu ft grow space in an in loses cabinet. Can I get way with 1 computer fan intake on the bottom and 1 intake computer fan on the top?

 

[FreezerBoy]

Intake fans are the one and only way to achieve positive pressure. Positive pressure, bad. Positive pressure, jail. Do not play with intake fans unless you're a pro.

You want negative pressure Negative Pressure for Dummies

Get a 4" hole saw. Punch 3 holes in the cab. One at top for exhaust fan, two at bottom for intake. You can make do with less but, this is the easiest, math free solution.

Given 21x21 is less than 3.1 square feet, not 171.5 square feet, I'd stick to the math free solution.

 

[Ryanobrian]

How many fans to properly vent my flower box

Thanks freezer it's 56" tall so I have about 14.29 cu ft is that 4" exhaust fan still sufficient? How many cfm will it need?

 

[FreezerBoy]

How hot is the room and how cool do you want the cab?



Ventilation 101

 

[Ryanobrian]

How many fans to properly vent my flower box

Okay so the ambient room temp is 75*. Cab temp is 95*. So by the graph because there is a 20* different I should put one exhaust fan pumping 25CFM? That dosent sound like much?

 

[FreezerBoy]

Given 75º ambient temps, 25 cfm will maintain cab temps at 95º. You'll need 470 cfm to drop cab to 76º

 

[Ryanobrian]

Given 75º ambient temps, 25 cfm will maintain cab temps at 95º. You'll need 470 cfm to drop cab to 76º

holy shit?! So I have to basically get a 450CFM vortex fan as an exhuast out the top with progressive intake? that sounds like an overkill

ps thanks for your help freezer I'm obviously learning

 

[hazydreams]

Freezer boy - that jpg of the fan size need per light is TITTIES!!!!

wish i saw that before i went all trial and error.

250 cfm dayton axial will do it exhausted to the atmosphere. if being exhausted into a carbon filer i would look into an inline blower. theres a nice 6" on ebay for 75 bill plus shipping advertised at 530cfm...... i have one and its on a speedster just idling away at 75% keeping my cabinet at 3-5 degrees over ambient. more is better when it comes to HVAC. unless in a very very cool place you'd have to try really hard to over cool a grow room...

 

[Ryanobrian]

allright i just got this guy on ebay www.xr.com/daytona I'm ganna mount it as my exhaust out the top.... I'm not ganna use a carbon filter.... This should be good right? How big/ many should my progressive intake be?

 

[FreezerBoy]

I'm not ganna use a carbon filter....

I hope you like jail.

 

[Ryanobrian]

I hope you like jail.

huh? good thing im a patient

 

[FreezerBoy]

In that case, enjoy the home invasion.

 

[midgethorse]

Yea like freezer said,
When they start hammering holes in your walls looking for secret compartments and trash your place, youll wish you were a bigger fan of carbon.

Its the key component to saftey, that and your mouth.
Midgethorse.