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Small Closet Grow Exhaust Fan

Die Hard

New Member
Hola! I'm converting a 27" X 27" X 8' closet into a micro grow. If I mount a conventional bathroom fan in the ceiling of my closet, and allow intake air to enter passively at the bottom, will this provide enough fresh air for The Girls? I'll be lighting with a 240W QB set-up from Timber. If this is way way wack, please advise.
I do intend to fit a carbon filter in there somewhere, and "ducting" the outflow through my attic, to an eave vent.
Thanks, gang!
 

Oldbear

Well-Known Member
If you have a fan rated around 100 cfm that should be great. You are at 32 cuft so even a 50 cfm would help. The filter is usually on the intake side of the fan which would be a problem with a ceiling fan.
 
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Die Hard

New Member
If you have a fan rated around 100 cfm that should be great. You are at 32 cuft so even a 50 cfm would help. The filter is usually on the intake side of the fan which would be a problem with a ceiling fan.
Thanks, Oldbear. I realized that after I posted (filter on intake). Maybe I can find a plenum that would fit over the fan, and come to a 4 or 6 inch flange?
Getting too convoluted - better get the proper equipment. Thanks again!
 

Bonsaiweed

Member of the Month: May 2018
Hola! I'm converting a 27" X 27" X 8' closet into a micro grow. If I mount a conventional bathroom fan in the ceiling of my closet, and allow intake air to enter passively at the bottom, will this provide enough fresh air for The Girls? I'll be lighting with a 240W QB set-up from Timber. If this is way way wack, please advise.
I do intend to fit a carbon filter in there somewhere, and "ducting" the outflow through my attic, to an eave vent.
Thanks, gang!

You may find that fan lacking. This is due to the fact is wasn't designed to be used with a carbon filter, and is probably underpowered. It could work, but if you start having an odor problem, that is where I would look first if you have a reliable carbon filter. I can tell you, you probably do not need more than about 190 cfm capable fan (smallest I could find on Amazon). I have a tent just smaller than your room (63 inches high), and a good 4-inch fan (centrifugal inline type off Amazon) will almost implode my tent on high. Also, you may want to control the speed of the fan for humidity/temperature control. That can be a huge deal.

I would probably wire in a speed control, and just use what you have for now, and possibly upgrade if it becomes a problem.

Just to be helpful....
 

Die Hard

New Member
You may find that fan lacking. This is due to the fact is wasn't designed to be used with a carbon filter, and is probably underpowered. It could work, but if you start having an odor problem, that is where I would look first if you have a reliable carbon filter. I can tell you, you probably do not need more than about 190 cfm capable fan (smallest I could find on Amazon). I have a tent just smaller than your room (63 inches high), and a good 4-inch fan (centrifugal inline type off Amazon) will almost implode my tent on high. Also, you may want to control the speed of the fan for humidity/temperature control. That can be a huge deal.

I would probably wire in a speed control, and just use what you have for now, and possibly upgrade if it becomes a problem.

Just to be helpful....
Good advice, to be sure! I have a bathroom fan in the shed ... but I'm gonna get a four inch, speed controlled, centrifugal inline. Got a favorite?
Thanks!
 

Bonsaiweed

Member of the Month: May 2018
I got the Ipower setup on Amazon. I would link it here, but that isn't allowed. :thumb:

I also added a speed control from active air from Amazon too
 

Die Hard

New Member
It's time to finalize my air handling. To review, my closet grow is 27" x 27" x 96".
I have a four-inch in-line fan (200 CFM with speed control) and carbon filter on order.
I have several options. I can draw in "household" air (seems like a no-brainer), but could use outddor, attic or crawlspace air. I can duct the exhaust air through the attic and out of a gable vent (nice, short run of 48"). I could also vent it into my walk-in pantry (open and doorless). I'm fairly certain I don't want to exhaust into the attic or crawl.
Any thoughts and/or advice, anyone?
Clones are coming Friday!
 

Die Hard

New Member
Me I would go for inside air intake and exhaust through the gable vent.
Thanks OB! That was my plan all along, until I awoke in the night and asked myself "what if...?".
I have four inch ductwork (not the flexible clothes dryer stuff). Will the average fan/carbon filter flanges accept this?
You da man!
 

Bonsaiweed

Member of the Month: May 2018
I plan to vent through a window when the temperature gets higher. Right now, I'm just venting into the same room as my tent to retain heat. It's a poorly insulated room.
 

Oldbear

Well-Known Member
They should be fine if you start with the uncrimped end of the pipe at the fan. Best to insulate the pipe that is in the attic if you are in a cold in winter area. Other wise you will get a condensation buildup.
 

Bonsaiweed

Member of the Month: May 2018
They should be fine if you start with the uncrimped end of the pipe at the fan. Best to insulate the pipe that is in the attic if you are in a cold in winter area. Other wise you will get a condensation buildup.
That is good information, and some many do not think about. Like me.... :thumb:
 

Die Hard

New Member
I plan to vent through a window when the temperature gets higher. Right now, I'm just venting into the same room as my tent to retain heat. It's a poorly insulated room.
No odor? It would be easier for me to vent into my pantry. A simple 4 inch hole, minimal ducting, and more efficientcy. Having never done or seen this equipment in operation, I don't know what to expect. I'll have four plants crammed in there, with 240 watts of Quantum Board. Shouldn't be much heat gain (right?), but I don't know what to expect regarding odor, humidity and noise.
 

BigBearNTexas

Well-Known Member
I grow using a small text 2’x2’x4’ and tried to get away with a small fan used to cool electronics. It would have been fine if all I wanted was to turnover the air; the whole tent is 16f^2, and this small fan is rated at 26f^2 per minute. But I wound up having to upgrade to a 4” inline fan when I added the carbon filter. The original fan was $25, the upgrade was $30. I would have saved money if I had done it right the first time.

(BTW, when the stain description says “low odor” that doesn’t mean its still not going to stink up the house. Lol)
 

Bonsaiweed

Member of the Month: May 2018
No odor? It would be easier for me to vent into my pantry. A simple 4 inch hole, minimal ducting, and more efficientcy. Having never done or seen this equipment in operation, I don't know what to expect. I'll have four plants crammed in there, with 240 watts of Quantum Board. Shouldn't be much heat gain (right?), but I don't know what to expect regarding odor, humidity and noise.

I have a carbon filter inside my tent, the exhaust fan pulls through. It will help to minimize/remove the odor. That isn't easy on a very small grow. Also because I only have 63 inches total height, I will always have to train (LST, HST, suppercropping, etc.) I haven't gone through a flowering cycle yet, so I can't state about odor yet.

My fan is actually quite loud, even with it hanging by zip-ties. It is hung outside my tent due to space.

I'm having humidity swings due to the weather, but I plan to add a humidifier and a dehumidifier. Always a struggle against mother nature.
 
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Bonsaiweed

Member of the Month: May 2018
I grow using a small text 2’x2’x4’ and tried to get away with a small fan used to cool electronics. It would have been fine if all I wanted was to turnover the air; the whole tent is 16f^2, and this small fan is rated at 26f^2 per minute. But I wound up having to upgrade to a 4” inline fan when I added the carbon filter. The original fan was $25, the upgrade was $30. I would have saved money if I had done it right the first time.

(BTW, when the stain description says “low odor” that doesn’t mean its still not going to stink up the house. Lol)

How well is your carbon filter worked so far?? Just asking, cause I haven't put mine to the test yet.
 

BigBearNTexas

Well-Known Member
The carbon filter worked great for the first three or four months, but it’s time to get a new one. I’ve been noticing more smell in the room lately. Purchased it in October, so that’s about the lifespan I was expecting. It’s a $36 filter, so it won’t break the bank to get a new one.
 

Bonsaiweed

Member of the Month: May 2018
The carbon filter worked great for the first three or four months, but it’s time to get a new one. I’ve been noticing more smell in the room lately. Purchased it in October, so that’s about the lifespan I was expecting. It’s a $36 filter, so it won’t break the bank to get a new one.
Was you running it 24/7 the whole time?? Just trying to get a handle on the hour usage.
 
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