Do I need 2 exhaust fans to do this correctly?

JSB99

Well-Known Member
I've been out for a while but now I'm setting up a new closet grow and I'm having a dilemma about the exhaust fan(s).

I plan on getting a 6" Can Fan Max to exhaust my vented hood (600w lights). The air will come from the outside and exhaust to the outside. I want this sealed so I don't have any odors escaping, plus I don't want to have to rely on an ac to control the heat.

What I'm wondering is, do I need to get another exhaust fan to exhaust the air from my grow, mother, and clone areas, or can I use a splitter with the can fan so it serves both purposes? I plan on using a carbon filter as well.
The carbon filter would cause resistance on that side of the splitter so I imagine the majority of the intake would be from the hood ducts rather than the inside of the grow areas.

Would enough get drawn out of the areas (if any)? I wonder if I put some nylon over the fresh air intake going to the hood (which I should probably do anyways to keep the debris out) if that would balance it out.

Anyone have some experience with this?
 

Tone5500

Well-Known Member
I would suggest pulling the air from a cool room next to your grow and the exhaust to attic or outside if your draw te air from outside and the temps/ humidity are high you might run into so heat issues, but if you have nice cool summers you be good but two answer your question I would run 2-3 depending on the size of your grow areas
 

hydroMD

Well-Known Member
You could just leave one side of your hood open and exhaust througg a carbon filter. That would even up your pressure. Buy one 10-12" fan amd set up a cfm adjuster that way u can up tue flow if things get hot.
 

hydroMD

Well-Known Member
Then just have a cool air intake that will teplace hot air with cool air. Wont have to worry about smell with negative pressure and your carbon filter
 

Holy Grail 888

Well-Known Member
I would suggest pulling the air from a cool room next to your grow and the exhaust to attic or outside if your draw te air from outside and the temps/ humidity are high you might run into so heat issues, but if you have nice cool summers you be good but two answer your question I would run 2-3 depending on the size of your grow areas
why not pull cold air from under the house and always have cold air about the same temp to give stability to temps.
just a thought but not always poss..

:blsmoke:
 

Tone5500

Well-Known Member
There's not one set way , but for me I live in te southwest America where the temps in the summer are 100 plus got 3 months to draw air from the outside is not possible , and I started off with a open end cool tube, and it worked but I had to seal up my ac ducting due to the fact the inline fan pulled warm air Thur the ducting when ac was off so it just much easier in my situation to draw cool air from the room next door a push air up into my atic , but climate , house , a lot a variables . Just try some thing out find out what works for you
 

JSB99

Well-Known Member
My grow will have 3 sections:
4x4x7 grow area 400w Sunmaster for veg / 600w Sunmaster for flower using a vented hood with a Lumatek lk600/240v dimmable ballast
2x4x4 for 3 or 4 mothers under a Slimstar 4ft 6-lamp t5 hood
2x4x3 for clones under a Growbright 2ft 4-lamp t5 hood

Grow will be in a separate outdoor shop with space underneath the structure. That's where I'll draw fresh air and I'll exhaust it through the top.
I live in the Northwest so it doesn't get all that hot. In the summer I was going to run night lights, then reverse the schedule for the other 8 months.

All of my previous grows were all in various hydro/aero setups but I'll be using soil this time (except the cloner of course)

I figure I'll use a 6" can fan max with a muffler and controller for the hood and a 4" fan/filter combo for the areas.

Does anyone see any weaknesses with my equipment list?
 

TexasHank

Well-Known Member
I would recommend running 2 fans.. control is best.. speed controllers for every fan gives you an excellent control of your environment. That said.. this equipment can get expensive.

Good luck
 

SFguy

Well-Known Member
you think you need 2 6" fans for a closet grow??? im using 2 6" turbines for a 19X9 ft 3KW grow room. dont overthink this. if you have the knowledge to run a hydro setup then getting airflow and temp stability should be cake for you IMO.
 

JSB99

Well-Known Member
you think you need 2 6" fans for a closet grow??? im using 2 6" turbines for a 19X9 ft 3KW grow room. dont overthink this. if you have the knowledge to run a hydro setup then getting airflow and temp stability should be cake for you IMO.
It would actually be a 6" for the hood and a 4" fan/filter combo for the space.

In my last setup a few years ago I had a 8" can fan max pulling air through the open flange on the hood like described above (along with a filter). It was working great but I didn't get to see how it worked in the summer.

So maybe I'll just start with a single 6" and then move up if needed.

Thanks
 

JSB99

Well-Known Member
My grow space will only be around 140 cu ft (approx). The 6" fan will move around 330 cfm. Am I going to be going overboard? Would it be better to use a 4" fan with a reducer to both vent the hood and the room? Or should I just go with the 6" and bring the speed down with a controller?
 
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