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Ventilation

Zonked

Active Member
I'm working with a 5x5x7 grow tent. I have two fans inside to circulate the air and a 195 CFM exhaust fan connected to a 4 in filter. My question is do I need a second fan for intake or would leaving an exhaust flap open be enough to bring fresh air in? Thanks.
 

Greenlizard

Well-Known Member
Hi Zonked.
I personally have a similar setup. I however do not have a fan "pushing" or "pulling" air into the tent other than the negative pressure created by the exhaust fan. Leaving a "flap" open in my mind makes me worry about light leaks (depends on your setup).
In order to help increase the air change in the tent I made use of one of the ports in my tent. I used a 6 foot length of 4" ducting and ran it through the port. This reduced the suction on the tent slightly and increased air flow. Sucking air from the floor is your coolest air to supply the tent with. Also be sure to put a S or curve in the ducting to avoid light from passing through it into the tent.
 

Zonked

Active Member
Hi Zonked.
I personally have a similar setup. I however do not have a fan "pushing" or "pulling" air into the tent other than the negative pressure created by the exhaust fan. Leaving a "flap" open in my mind makes me worry about light leaks (depends on your setup).
In order to help increase the air change in the tent I made use of one of the ports in my tent. I used a 6 foot length of 4" ducting and ran it through the port. This reduced the suction on the tent slightly and increased air flow. Sucking air from the floor is your coolest air to supply the tent with. Also be sure to put a S or curve in the ducting to avoid light from passing through it into the tent.
Thank you for the response, I will have to get to the hardware store and get some ducting to avoid that light leak. Does your tent stink up the house? My girls are early in flowering so it's not much of an issue yet but I am in an apartment.
 

Greenlizard

Well-Known Member
I have not noticed any odor yet in my house. I am on week 4 of flower. From what I have been reading the really strong odor doesn't come until the last couple weeks. Probably has a lot to do with the strain as well. I am currently venting the air back into my house to make use of the heat but if odor becomes a problem I will vent it outside.
 

George Mc

Well-Known Member
I have not noticed any odor yet in my house. I am on week 4 of flower. From what I have been reading the really strong odor doesn't come until the last couple weeks. Probably has a lot to do with the strain as well. I am currently venting the air back into my house to make use of the heat but if odor becomes a problem I will vent it outside.
If you have someone you can trust that doesn't live in the house have them come over and see if they can smell something in the house. You're probably is an older you're just not picking it up because you live there
 

Zonked

Active Member
If you have someone you can trust that doesn't live in the house have them come over and see if they can smell something in the house. You're probably is an older you're just not picking it up because you live there
Would adding a 100cfm fan to the intake ducting eliminate any odor from escaping from there? Or would that not be an issue anyway? Thanks again guys
 

Gadfly

Well-Known Member
You want a fan roughly 2x the cfm of your cubic footage. Adding another fan will help w circulation but you won’t get the desired results from a carbon filter without creating negative pressure. You want to see the tent suck in when all zipped up.

You have a great size tent. I’m jealous. However, the exhaust fan you’re using is too small and underpowered especially if odor control is a factor. I’d look for a 6 inch with twice the cfm and not bother with an intake fan. But that’s me.
 

George Mc

Well-Known Member
Would adding a 100cfm fan to the intake ducting eliminate any odor from escaping from there? Or would that not be an issue anyway? Thanks again guys
I was just talkin about this on a thread a couple days ago. Odds are there will be an odor of cannabis in the house that you cannot smell because you're in the house with it. Fans definitely help with a carbon scrubber but maybe trying to disguise the smell with something else might help. Stinky house plants, potpourri placed around the house or if you're expecting company have something already cooking that has a heavy Aroma before they get there. I really think there should be a thread about this subject because a lot of people are growing illegally
 
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