intake/exhaust/carbon filter...

Ok I'm glad there is a place like this to ask questions that I should know the answer to.

Ok I have a grow room that is
W. 0.7m
L. 1.5m
H. 2.5m
Will be using 1200w LED lights and growing d.w.c.

I have worked out what size or cfm rating I need, what I need to know is...

So I need an intake fan, exhaust fan and carbon filter? Or do I just need to use 2?
Smell is an issue, neighbours are used to the smell of smoked green not fresh green.

Any help will help lol
 

Leotime21

Well-Known Member
Hey friend, im not entirely sure how hot 1200w LED's get I'm only used to working with MH/HPS. But I would suggest having a exhaust fan with a carbon filter hooked up FOR THE BARE MINIMUM!! But that does depend.. how many plants do you plan on growing?
 
I have been told that they do not get very hot and have not checked the temps yet but can have my hand placed quite close without burning myself
I'm only growing 2 as its my first time.
I don't mind buying all 3 if I have to, just didn't want to spend money I didn't have to.
The way I had it planned in my head was...
Intake fan in the door to my grow room (walk in wardrobe in bedroom) carbon filter hanging from ceiling and another fan/exhaust hanging from ceiling with ducting transporting hot air outside of my grow...is this a correct way of thinking?
 

Leotime21

Well-Known Member
Well then if temps arent an issue you might get away with a setup like this then:
Carbon filter in your grow room ( walk in closet) AND Exhaust fan with ducting will export the hot air out and you could have a box fan bring air in from the front of the room. However you are on the right track. But I don't think IMO that you will need a powerful intake fan.... def not.
 

blackforest

Well-Known Member
You need at least one intake and one exhaust. You want your exhaust fan hooked up to a carbon filter and have that fan more powerful than your intake so you create negative pressure which basically means it's pulling all the air in the grow area through the carbon filter.
 
Thanks for the advice guys. After reading this and talking to the local hydro store I'm going to just get the carbon filter and extractor for now, I have about 2 inch's at the bottom of my door for a bit of air to get in and it is close to a window. I will run lights and filters then check temps, humidity and airflow....will then take it from there.

Thanks again
 

NorthofEngland

Well-Known Member
You need at least one intake and one exhaust. You want your exhaust fan hooked up to a carbon filter and have that fan more powerful than your intake so you create negative pressure which basically means it's pulling all the air in the grow area through the carbon filter.
Negative pressure occurs when fans are taking more air out than is coming in.
A vacuum is created - like when a tents sides look sucked in...?

Most rooms/tents don't need a 2nd intake fan.
The negative pressure sucks in air thru the laws of physics.

A length of ducting from where ever you feel the best fresh air is to inside your room will help you manipulate the best air going to the best place
But a 22nd intake fan isn't necessary unless your using a sealed room and CO2....

LEDs do not produce much heat so that's yet another reason not to go overkill with the fans.
You're not combatting heat build up like HID users.
 

blackforest

Well-Known Member
Negative pressure occurs when fans are taking more air out than is coming in.
A vacuum is created - like when a tents sides look sucked in...?

Most rooms/tents don't need a 2nd intake fan.
The negative pressure sucks in air thru the laws of physics.

A length of ducting from where ever you feel the best fresh air is to inside your room will help you manipulate the best air going to the best place
But a 22nd intake fan isn't necessary unless your using a sealed room and CO2....

LEDs do not produce much heat so that's yet another reason not to go overkill with the fans.
You're not combatting heat build up like HID users.
I didn't realize you were growing in such small conditions. But for most grows, yes, you want fresh air intake as well as exhaust.
 

TonightYou

Well-Known Member
Thats a small grow, just an exhaust fan will do. Think of what you want to buy, and then buy bigger. A strong fan really does a great job at pulling through a ton of heat and scrubbing the odor.
 
Thanks mate, love a bit of science.
Yeah it is small, I have a 2 inch gap at the bottom of the doors to my grow room, should I put drought excluders over it or use that as a way for the negative pressure created to suck air in?
I was going to cover the gap as I'm worried about bugs but good ventilation is more important .

Will do a test run and check the temps/humidity
Was looking at this for a carbon filter/ extraction fan
http://www.greensea-hydroponics.co.uk/shop/acoustic-extraction-kits.html
Its in my bedroom so want something silent.

Thanks guys
 

Jeremy13

Member
Negative pressure occurs when fans are taking more air out than is coming in.
A vacuum is created - like when a tents sides look sucked in...?

Most rooms/tents don't need a 2nd intake fan.
The negative pressure sucks in air thru the laws of physics.

A length of ducting from where ever you feel the best fresh air is to inside your room will help you manipulate the best air going to the best place
But a 22nd intake fan isn't necessary unless your using a sealed room and CO2....

LEDs do not produce much heat so that's yet another reason not to go overkill with the fans.
You're not combatting heat build up like HID users.
If you are using a 2nd intake fan and that would mean you have 2 intake fans in a (sealed room) wouldn't that not be a sealed room, my understanding is a sealed room uses NO intake or exhaust hence the term (SEALED)
 
I too thought this but being a noob thought I had it wrong.
I'm quite happy I don't have to buy a intake fan now. Just a quiet exhaust, carbon filter and silencer!
 

Leotime21

Well-Known Member
Hey man!
Yeah I would go about just creating negative pressure and see how that allows the humidity and temp to get to. Also you mentioned the kit. Im not sure about that particular brand but I can tell you that you can muffle the sounds of the extract fan. What I did was just cut two holes (the size of your ducting IE: 4"..6" etc) in a tote and fill it with packing peanuts ( however any insulator probably will work ) now hook up all your equipment one with the carbon filter at one hole and the ducting running from the fan out the other hole and out your grow room.

This cut my noise down A LOT. I would hear my fan walking up the stairs. After I did this I no longer even knew the fan was on until I was around the room. In my own place I wouldn't mind a little air movement noise.
 
Never thought about that...will keep that in mind thanks.
I'm feeling to get a silencer as well as doing what I can diy wise to block sound out. Going to sound proof the room as best as I can too
 

JohnDee

Well-Known Member
HK,
I've set up various rooms over the years and have always gotten by nicely with passive intake air and a nice strong exhaust through the scrubber. Mostly I've used a light tight vent such as a "darkroom" vent for passive intake.
JD
 

TonightYou

Well-Known Member
Hey man!
Yeah I would go about just creating negative pressure and see how that allows the humidity and temp to get to. Also you mentioned the kit. Im not sure about that particular brand but I can tell you that you can muffle the sounds of the extract fan. What I did was just cut two holes (the size of your ducting IE: 4"..6" etc) in a tote and fill it with packing peanuts ( however any insulator probably will work ) now hook up all your equipment one with the carbon filter at one hole and the ducting running from the fan out the other hole and out your grow room.

This cut my noise down A LOT. I would hear my fan walking up the stairs. After I did this I no longer even knew the fan was on until I was around the room. In my own place I wouldn't mind a little air movement noise.
that is fuckin brilliant! I'm going to try the tote bag idea. I currently just hang my fan, this would totally help on silencing the fan further
 
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