Properly venting a room

TreeFiddy350

Well-Known Member
If I’m trying to properly vent my shop, which is approx 35x25 with about 15ft ceilings, I would want an exhaust of about 13,125 cfm, right?
As well as an air intake to bring in fresh air of about the same cfm at a minimum, right?
just trying to make sure I’m not overdoing it.
 

NeWcS

Well-Known Member
With that many cfm's sucking air out, the pressure would be negative thus pulling ouside air in. You could use passive intake and not have a fan at all(on the intake). IMO
 

rob333

Well-Known Member
If I’m trying to properly vent my shop, which is approx 35x25 with about 15ft ceilings, I would want an exhaust of about 13,125 cfm, right?
As well as an air intake to bring in fresh air of about the same cfm at a minimum, right?
just trying to make sure I’m not overdoing it.
dude you so need 3 Asians with cardboard squares waving the shit around
 

TreeFiddy350

Well-Known Member
Actually... if I wanted the air to exchange 3 times in the hour, I would want the 13,125 times 3 giving me 39,375. Divided by 60 to give me 657.25cfm.
Does that sound right?
 

NeWcS

Well-Known Member
If I’m trying to properly vent my shop, which is approx 35x25 with about 15ft ceilings, I would want an exhaust of about 13,125 cfm, right?
As well as an air intake to bring in fresh air of about the same cfm at a minimum, right?
just trying to make sure I’m not overdoing it.
To add; You said 'workshop', not sure if thats code for growroom but if it is indeed a workshop, I would guess you wont have carbon filters hooked to those output fans. This will really help create a a better 'vacum' effect, then if you were to put filters on them. If you are in fact going to use a filter then a intake fan might be needed.

I would go over board if you can afford it, and use speed controllers to dial it in. Also, I would spread your cfms out over muti-fans.
 

NeWcS

Well-Known Member
Actually... if I wanted the air to exchange 3 times in the hour, I would want the 13,125 times 3 giving me 39,375. Divided by 60 to give me 657.25cfm.
Does that sound right?
There is a formula you can use to better know what to shoot for. I assume thats what you're using. Stick to that, or like I said; go overboard
 

TreeFiddy350

Well-Known Member
To add; You said 'workshop', not sure if thats code for growroom but if it is indeed a workshop, I would guess you wont have carbon filters hooked to those output fans. This will really help create a a better 'vacum' effect, then if you were to put filters on them. If you are in fact going to use a filter then a intake fan might be needed.

I would go over board if you can afford it, and use speed controllers to dial it in. Also, I would spread your cfms out over muti-fans.
yeah it’s for a grow. It’s not like maxed out or anything, but I would like to max it eventually. Right now it’s an open space for flowering.
I currently have 3 passive exhausts to the roof (or I think that’s what it would be called)
So I was thinking attaching something that’s about 600cfm on each exhaust. Then maybe having a passive air intake like you were saying
 

TintEastwood

Well-Known Member
Thats a huge space. I'm jealous. Lol

If you need some fan control, there are AC Infinity fans with onboard controllers. I love my T6.

Any plans to have separate tents or rooms in the space?
 

TreeFiddy350

Well-Known Member
Thats a huge space. I'm jealous. Lol

If you need some fan control, there are AC Infinity fans with onboard controllers. I love my T6.

Any plans to have separate tents or rooms in the space?
does that sound right as far as my cfm goes for air circulation? The more I read, the more I’m getting confused. Yeah once I get more money coming in, I’ll prob build 2 rooms that like 10x10x8 or something like that. I would like to eventually dabble with some co2
 

TreeFiddy350

Well-Known Member
But as of right now I don’t plan on having rooms. Just trying to properly ventilate this room.
jjst trying to figure out how many exhaust fans/ Cfms I’ll need total
 

TintEastwood

Well-Known Member
But as of right now I don’t plan on having rooms. Just trying to properly ventilate this room.
jjst trying to figure out how many exhaust fans/ Cfms I’ll need total
Wish I knew more cfm tech, no need to get into that with my lil 4x8x8.

Looking forward to seeing your dank grows.

(I'm sammiched between 2 pits - lol)
 

bk78

Well-Known Member
I JUST NEED TO GET OFF HERE. YOU ARE THE GROWERS THAT CONTRIBUTE TO THIS BULLSHIT THAT GROWING POT IS SO COMPLICATED. THE PLANTS NEED THE SAME THINGS WE NEED. NOT ALL THIS CONTROLLED ENVIRONMENT.
JUST KEEP SPENDING MORE MONEY.
Sounds like you need to worry about yourself and your environment and not others on the internets
 

JavaCo

Well-Known Member
Is 13,125 cfm the MINIMUM? I thought I read somewhere that you want it exchanged 2-3 times a minute. Does that sound right?
One to two changes a minute is what that calculator says. But yeah that number is the minimum. That should be fine for a room 2 changes a minute would be more for a greenhouse in full sun during the hottest part of the day.
 

TreeFiddy350

Well-Known Member
One to two changes a minute is what that calculator says. But yeah that number is the minimum. That should be fine for a room 2 changes a minute would be more for a greenhouse in full sun during the hottest part of the day.
Holy shit man. I’m looking up these exhaust fans... phew. I’m gonna need a few big ones.
how bad do you think it would be have about 6000-10,000 cfm starting out?
These things are kinda pricey haha
 

JavaCo

Well-Known Member
Holy shit man. I’m looking up these exhaust fans... phew. I’m gonna need a few big ones.
how bad do you think it would be have about 6000-10,000 cfm starting out?
These things are kinda pricey haha
What kind of lights are you going to use. Quality LED give off quite a bit less heat then HPS lights so you could get by with a bit less CFM. If you are not filling the entire room full of plants you can also get by with less CFM. Thats quite a bit of space you going to fill it up? If so I wouldn't skimp too much on the CFM rating. That many plants in the middle of flower will fill that room up with humidity very fast so high CFMs help keep it down so you dont get any mold or mildew. But a small area like a 5x5 won't affect all the rooms air so you wouldn't need 12000 CFM. 240CFM would do a 5x5 tent. Those fans are 20 bucks. Fans i am using for my greenhouse are for cars 12 volts do 2000 cfm a minute 14 inches wide. 6 of those would put out 12000 cfm and costs about 90 bucks for 6 of them 3 PWM controllers would be 45 dollars I plan on using solar for mine but you can get 12 volt 200 watt PSU's for about 27 a peice so another 80 dollars. So you could DIY it if you had space for six 14 inch fans for about 250 -300 dollars. Bad is no odor control not sure if you want the neighborhood smelling or not.
 

DailyBlastin

Well-Known Member
honestly what you need to do is divy the space. either use tents or build walls, then you can use appropriately sized fan+filter for extracting each area seperately, if you do that and run a mini split in the main workshop for heating/cooling then passive intakes for each divided area. thats how id do it anyway, otherwise you're gonna end up spending a shit ton on equipment thats not meant for a space that large, probably burn out some fans in the process, and still not have a controlled environment..
 
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