How to vent a grow room?

Peaceful Smoker Of Weed

Peaceful Smoker Of Weed

Well-Known Member
Grow room.jpg Grow room.jpg I'm building a grow room in my garage and I need a little advice please...

My room is in the garage, and one wall has the laundry room directly on the other side. I was going to put a 4 inch pipe just for air intake, so I would have fresh air coming in from the laundry room.

On the top I have a 6 inch in line fan connected to a 6 inch pipe going out the roof.... My question is will the suction from the fan automatically pull in air from the laundry room, or do I need to install 2 fans, one for "in" and one for "out"?

Any "diy" peeps out there have any input that would be awesome. Thanks in advance.
 
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meangreengrowinmachine

meangreengrowinmachine

Well-Known Member
what you are speaking of is called "negative pressure" and it will depend on the CFM rating of your 6 inch inline fan vs the size of your room. If the CFM rating of your fan is higher than the cubic footage of your room, you will have negative pressure. This is also a MUST if you are needing to be stealth and don't want smell seeping out of your room. i have my room temp set up with a make shift door of panda film and it suctions the thing right to the walls when i close it up to help with light leaks as well as smell. I plan on getting light proof vents (like for a darkroom) and installing those once I install the door. Keep in mind that your 4 inch pipe may leak light from your laundry room so you may want to look into light proofing it.
 
Peaceful Smoker Of Weed

Peaceful Smoker Of Weed

Well-Known Member
meangreengrowinmachine said:
what you are speaking of is called "negative pressure" and it will depend on the CFM rating of your 6 inch inline fan vs the size of your room. If the CFM rating of your fan is higher than the cubic footage of your room, you will have negative pressure. This is also a MUST if you are needing to be stealth and don't want smell seeping out of your room. i have my room temp set up with a make shift door of panda film and it suctions the thing right to the walls when i close it up to help with light leaks as well as smell. I plan on getting light proof vents (like for a darkroom) and installing those once I install the door. Keep in mind that your 4 inch pipe may leak light from your laundry room so you may want to look into light proofing it.
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Thanks for the info. I have a couple bends purposly to stop light leaks. I hope it works.. YouVent.jpg think it might fly?
 
meangreengrowinmachine

meangreengrowinmachine

Well-Known Member
painting the inside flat black will go a long way to make sure the light doesn't go around those bends also. Keep in mind as a rule of thumb you want twice as much intake as you do going out... so with a 6 inch output fan you would want approx. 12 inches of intake IDEALLY.. will it work with the 4" pipe yes, but just saying something to shoot for down the road.
 
Peaceful Smoker Of Weed

Peaceful Smoker Of Weed

Well-Known Member
meangreengrowinmachine said:
painting the inside flat black will go a long way to make sure the light doesn't go around those bends also. Keep in mind as a rule of thumb you want twice as much intake as you do going out... so with a 6 inch output fan you would want approx. 12 inches of intake IDEALLY.. will it work with the 4" pipe yes, but just saying something to shoot for down the road.
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Well I havent installed it yet. two 6 inch holes in the laundryroom seems a bit much, but maybe Ill start with 6inch for both in, and out.
 
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Dylan1234324

Active Member
On my grow box i just used a cheap 305 cfm floor fan from menards and have a 6 in intake but im a newbie seems to be working okay
 
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Dylan1234324

Active Member
Do you have a extra spot to hook the intake to the furnance ? Then run the furnance fan on and only need one exhaust fan and your temps should be okay .
 
klx

klx

Well-Known Member
I prefer 2 fans because if you have passive intake the hole needs to be twice the size of your exhaust fan. A 4" fan as intake and a 6" fan as exhaust will give you a nice negative pressure and would be what I would do.
 
Jjlaw95

Jjlaw95

Active Member
If you want stealth go for Carbon filter I've planned out an operation for a shed in the back garden i only got stuck on installation to keep heat in ✌
 
Tomula

Tomula

Active Member
Peaceful Smoker Of Weed said:
Thanks for the info. I have a couple bends purposly to stop light leaks. I hope it works.. YouView attachment 4119207 think it might fly?
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That should work for the light, but note that any bends will decrease airflow of your fan and can add some acoustic pressure- noise. Straight tubing is better at venting than flexible pipe, though, kudos for that. You can also get kitchen hood filter in form of black/white cloth that will stop some smell and also some light. That's my 2 cents, good luck.
 
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Beachwalker

Well-Known Member
I have one of those cheap inline fans on my Inlet but I seldom ever use it, only on the hottest days (when I have everything going:?) your tent will bring in the air on its own with the 6-inch inline, a bend is a good thing to block the light, looks good, when you get it completed stand in there and it should be all Dark, and that way you can chase any Light leaks too
-good luck!:leaf:

* by the way I'd recommend against ever using your furnace exhaust for anything other than a furnace exhaust
 
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Dylan1234324

Active Member
It is not the exhaust i had a extra hookup for ducting in my basement same air that goes in the rest of the house, it seems to be working for me and keep temps where i want them . Why do you say to never use it ? Im a newbie
 
Bernie420

Bernie420

Well-Known Member
Is there a reason you cant pull air in from the garage. Is it too cold or going to be to cold? You could get by with just the four inch in and a carbon filter on a six fan exhausting out. you'll probably be drawing air in from around the door a little as well. You could build a light proof box in between the studs and draw air from that in the summer and from the four inch in the winter .and what im talking about is have a vent at the top of the wall in the garage and box cover both sides between the studs you have a top vent and then put a bottom vent on the inside of the grow room. light doesnt get out this way.
 
Bernie420

Bernie420

Well-Known Member
Dylan1234324 said:
It is not the exhaust i had a extra hookup for ducting in my basement same air that goes in the rest of the house, it seems to be working for me and keep temps where i want them . Why do you say to never use it ? Im a newbie
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Its just a bad idea all the way around you dont really want the noise from your furnace running 24/7 exhaust gasses from the furnace getting pushed back into the house exhaust from the furnace going into your grow room. Wear and tear on the furnace. You dont know what this guy has for a furnace or if he could even hook it up right he could fuck it up and kill everybody with carbon monoxide gas. Not going to debate it with you its a bad idea period. I dont know what you did at your grow and how you ran your ducting but I dont want to debate that either:peace::peace::peace::peace::peace:bongsmilie
 
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Beachwalker

Well-Known Member
Dylan1234324 said:
It is not the exhaust i had a extra hookup for ducting in my basement same air that goes in the rest of the house, it seems to be working for me and keep temps where i want them . Why do you say to never use it ? Im a newbie
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I once worked as a state licensed burner technician, it's possible for carbon monoxide to enter living space when people start altering their exhaust.

If you sure it's not the exhaust then it should be all right, but definitely double check. I would never recommend venting out a chimney.
 
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Dylan1234324

Active Member
I know for a fact it is the ducting lol and i just bought a brand new furnance last winter but it was the only way i could do it since im in the cold basement and the extra duct work was right there .
 
Michael Huntherz

Michael Huntherz

Well-Known Member
Beachwalker said:
I once worked as a state licensed burner technician, it's possible for carbon monoxide to enter living space when people start altering their exhaust.

If you sure it's not the exhaust then it should be all right, but definitely double check. I would never recommend venting out a chimney.
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Agreed, you can die unless you know precisely how the hvac system works and play by those rules.
 
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