Where Can I Vent My Air?

my rooms will be in my crawlspace... it's the best spot for it, however, i have one major issue...

my ventilation system, will be 100% contained in the crawl space. My main goal is to vent this exhast through my roof (possibly merging ducts with my bathroom exhaust fan so i don't have to punch another hole in the roof)..

i mainly want to do this so that any air that might possibly escape and may smell, (i am putting a can fan filter on it tho) will be released about 20 feet in the air, above anyone's head walking by...

i was planning to use reducers and run the exhaust up through the floor and through my walls (i'm very handy, i just gutted and rebuilt 90% of my house) using 2" PVC pipe... my main concern now is noise, if i try to send out roughly 150-300 CFM worth of air up through a 2" pipe (the duct started at 6") - won't all that air rushing through such a small pipe create a shitload of noise?

would i be safe enough to vent the air out into the crawl space, since it'd be after my carbon filter? what if i did that and put an air ionizer or two in the crawl space to double neutralize anythign that got passed the carbon filter..?

I'm super super super cautious. my whole room will be 100% soundproof, light-proof, air tight etc. my only remaining problem is where to vent the air.

150-300cfm ?! Shit that doesnt even cool my 1mx1mx1m grow tent lol , id say at least a 1000cfm if you planning on running long duct runs, especially through walls and floors etc.

also 6" to 2" ?! This will seriously restrict airflow.

i agree 6 to 2 is no good not only does it restrict the air exhaust way to much it over works the fan i would put it out the side of the houseand maybe attach a dryer vent to it to disguise it should not smell after its ran through a filter if it does stick a fabric softner in the vent my filter and cetrifigul fan runthrough the light and about 20 feet of ducting can not hear or smell it outside

It's going to get pretty hot up there!!

I have a very similar problem....Growing in a crawl space above the garage...I can see an existing flexible vent coming from the bathroom...So my plan is to get a Y vent adapter and split the existing pipe and place it in there so the air can not be forced back into the bathroom. Its not going to make much noise and the smell I am just going to use a carbon filter...

My grow room is 8' x 10'

This is exactly why I made this post... I just kept thinking to myself, venting a 600w flower room and a 400w veg room (total cubic feet is only 150, both rooms together) - I just thought that venting both rooms once per minute was going to be a bit much... more or less creating a wind tunnel!

Since sound is an obvious consideration, I don't want to be putting a 8" 765 cfm fan in there, i really think it's probably overkill, but then again, i have no experience running these bulbs, i know they get super duper hot. At least the 600w will be in a 6" cool tube, and the 400w will def be in an a/c hood at the very least.


I like the dryer vent idea and I could probably vent it right outside of the house at ground level. The problem is though that A, my real dryer vents to my patio, the only other options i have are to vent to my side yard towards my neighbor OR vent to the back of the house, which is again the patio... anyone sitting on the patio is going to hear/feel that vent CONSTANTLY blowing...

it just seems super impractical for me to vent upwards through pipe and so on and so forth... unless i had my 6" inline can fan, then have another fan in the attic (after the 2" pipe, before the vent outside) pulling the air through the wall as a "relay" type deal...

more thoughts?

Heemhoff17 said:

I have a very similar problem....Growing in a crawl space above the garage...I can see an existing flexible vent coming from the bathroom...So my plan is to get a Y vent adapter and split the existing pipe and place it in there so the air can not be forced back into the bathroom. Its not going to make much noise and the smell I am just going to use a carbon filter...

My grow room is 8' x 10'

Click to expand...

technically you're growing in the attic... the crawl space is UNDER the house, where it's much cooler to begin with (concrete floor and walls) -- above your garage, it's going to get blistering hot, unless you're either in canada or north of UK if across the pond...

defintiely going to need an air conditioner

just thought of one more question --

i'm going to be pulling a ton of air outta my rooms, the rooms will be as air tight as i can get them, therefore i need to pull air from somewhere... i CAN pull it right from the crawlspace which usually stays about 20 degrees (F) cooler than outside temps... but when it's 100 and humid outside, that still means it's a solid 80 or so (i haven't tested it in the summer yet, i'm speculating since right now it's 73 outside and about 51 in the crawl space)

my question is -- can i tap off of my HVAC supply line to force air into the room? since i'll be constantly venting that room, will i rob all of my air going into my house?!

My grow room is 6'x6'x8' using a walk-in closet in my condo. Using a 4" inline to vent carbon scrubbed air through 2 ft of 4" hose into the wall. There is a draft running through the crawl space in the wall with very cool air. Feels like outside air temps (very cold here) I'm guessing my air is getting swept away with the rest of the cold air. I don't really care much as scrubbed air doesn't stink and could go into the neighbors condo or outside, it doesn't much matter to me as carbon scrubbed air is no different than any other air you breath =)