I have a 10x20 ft space that will be fully insulated with R 21 on all sides. I'm new to growing so I'm not going to use it as a sealed room as of now. Here is a picture of the inner 2x6 wall that I'm framing in right now to make it fully enclosed. Its a breezeway between my garage and shop. I'm going to be running and undercurrent XL 16 with four California light work 880 LED lights to start. For my exhaust fan I have a 14 inch max fan 1700 CFM it will be on a thermostat. My question is I would like to use passive air for the intake and have the air sucked in from my garage I have a window in the far end of my garage that is about 1000 ft.² I am thinking that the air would come in and and warm up a little bit before it's pulled into the passive air vent into the room? I live in a colder climate in the winter so running these LEDs I don't think I want to be pulling in air directly from outside?
First Room Build And Grow!!
- Thread starter yukon369
- Start date
diamonddav
Well-Known Member
personally I would draw from the garage. its way to cold to draw from outside where im at. hell the garage might even be to cold!
jijiandfarmgang
Well-Known Member
I could never get a similar scenario to work.
Well, put it this way, I know it can work, but I was so frustrated I gave up and switched to sealed.
It would actually be easier to run sealed. At least in the colder months.
Having said that, my room was smaller (harder), and my climate is extreme. In my case running sealed became complicated, but thats a long boring story.
Here's what I see in your scenario -
Are your lights going to bring that room up to temp? If not, thats a big problem.
You'll need a dedicated fan for scrubbing if your worried about smell.
You'll need a dehumidifer
Your passive intake might let in cold air during lights out. (you could just get one of those passive damper intakes)
Depending on your intake temp if its really cool, and if the air exiting directly touches something like say a wall, it may cool it below the dew point and condensate like crazy. If your using drywall, it will mold in no time.
Basically, you will have to setup your fan and intake for temp, not for what someone says is proper exchange CO2. I've spent a lot of time testing this, and a lot of people just parrot information about room exchange per min bs. Sure its a good rule of thumb for run of the mill grow but not in your case and plants don't use that much CO2. So periodically cycling your fan will be fine. I've beat that horse to death in other threads if your interested.
- Jiji
Well, put it this way, I know it can work, but I was so frustrated I gave up and switched to sealed.
It would actually be easier to run sealed. At least in the colder months.
Having said that, my room was smaller (harder), and my climate is extreme. In my case running sealed became complicated, but thats a long boring story.
Here's what I see in your scenario -
Are your lights going to bring that room up to temp? If not, thats a big problem.
You'll need a dedicated fan for scrubbing if your worried about smell.
You'll need a dehumidifer
Your passive intake might let in cold air during lights out. (you could just get one of those passive damper intakes)
Depending on your intake temp if its really cool, and if the air exiting directly touches something like say a wall, it may cool it below the dew point and condensate like crazy. If your using drywall, it will mold in no time.
Basically, you will have to setup your fan and intake for temp, not for what someone says is proper exchange CO2. I've spent a lot of time testing this, and a lot of people just parrot information about room exchange per min bs. Sure its a good rule of thumb for run of the mill grow but not in your case and plants don't use that much CO2. So periodically cycling your fan will be fine. I've beat that horse to death in other threads if your interested.
- Jiji
Thanks for the input Jiji. I am definitely going to use a passive damper intake. The intake will come into the room from my heated garage that is about 1000 sq ft so i should be able to keep the intake air warm. I will also have a heater in the grow. I am very interested in your info on the proper air exchange for CO2. 
What size fan and Scrubber do you recommend for my room size 10x20x11?
What size fan and Scrubber do you recommend for my room size 10x20x11?
jijiandfarmgang
Well-Known Member
Oh....I didn't know your garage was heated and I'm assuming insulated. You can disregard a lot of my post then. That takes a lot of headache away.
On the scrubbing thing. You have a helluva exhaust fan. You could use two large Phat carbon filters with Y duct matched for cfm(possibly overkill). You could also look into an ozone chamber for your exhaust. If you don't only scrubbing it might get a little smelly outside late flower, its up to you.
I would get a large phat filter 10-12 inch opening with an 8 inch centrifugal fan for a 24/7 scrubber.
Bleh, there's a bunch of ways you can go about it.
Now that I think about it, I dunno what you would use for a passive intake with damper. You can get an active louvred one in any size. I've read that twice the area of the exhaust fan is a good rule of thumb. However in my experience thats too small. I tried it with a 2000 cfm fan and with intake open when you unlatch the door it practically opens for you.
Since someone could easily fit through this area, I used a metal grate screwed to the studs on the inside wall to cover the opening. Also sized and had some trim built so I can use standard furnace filters from a box store to filter my air.
- Jiji
Thats my advice off the top of my head how I would do it or try. Adjust to your needs. If you can run that exhaust fan outdoors, I doubt you have neighbours nearby.
http://rollitup.org/t/how-much-airflow-you-need-for-co2.852307/
On the scrubbing thing. You have a helluva exhaust fan. You could use two large Phat carbon filters with Y duct matched for cfm(possibly overkill). You could also look into an ozone chamber for your exhaust. If you don't only scrubbing it might get a little smelly outside late flower, its up to you.
I would get a large phat filter 10-12 inch opening with an 8 inch centrifugal fan for a 24/7 scrubber.
Bleh, there's a bunch of ways you can go about it.
Now that I think about it, I dunno what you would use for a passive intake with damper. You can get an active louvred one in any size. I've read that twice the area of the exhaust fan is a good rule of thumb. However in my experience thats too small. I tried it with a 2000 cfm fan and with intake open when you unlatch the door it practically opens for you.
Since someone could easily fit through this area, I used a metal grate screwed to the studs on the inside wall to cover the opening. Also sized and had some trim built so I can use standard furnace filters from a box store to filter my air.
- Jiji
Thats my advice off the top of my head how I would do it or try. Adjust to your needs. If you can run that exhaust fan outdoors, I doubt you have neighbours nearby.
http://rollitup.org/t/how-much-airflow-you-need-for-co2.852307/
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weednurd420
Well-Known Member
Never pull the air from out side, take advantage Of your heating and cooling in your home.
weednurd420
Well-Known Member
Looking good, I'm jealous lol
Thats the plan now Thanks!!
Thank you! Getting pretty excited to see what will happen!
401bigsm0ke
Well-Known Member
looks like a nice setup for just starting out. nice good luck
weednurd420
Well-Known Member
I'm sure its going to be all kinds of nice
Beer Belly
Well-Known Member
Agree I pull mine from my garage because its cooler for me. I'm in a warm climate. Comes in thru a Phresh intake filter via 6" dampered (spring type) passive intake. My output is a carbon scrubber in the groom vented to the attic pulled via a 8" fan and noise filter.
Does a great job but then your room is two times the size of mine and might need a bit more horsepower.
Awesome lookin room by the way! I'm jealous too.
https://www.rollitup.org/t/started-my-first-grow-room-come-along-for-the-ride.857393/
Yes I'm definitely pulling the air from my garage. What brand of damper did you get? I'm still figuring out what size passive air intake I need to make? My exhaust fan is a 14 inch max fan 1700 CFM it's a beast.
thank you!!