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Tutorial Ventilation 101

spaceboy

Active member
Hey guys, hoping somebody has an idea on a longstanding problem I've had....

My grow s in the basement and I've got only 2 very small windows about 3.5"x9" to exhaust out of. I'm trying to run my 8" 737cfm can fan out it, but it seems the opening isnt big enough for the fan to work properly and its not nearly enough to cool my room.

Room is 6.5'x7'x14' and am running 3 bare bulb 600's, about to be running 3000w bare bulb.

I'm wondering if I would be better off exhausting into my lung room instead of straight outside, that way I can get a larger fan and have it working at optimal efficiency so nothing is obstructing its flow. I would then have to get another fan to exhaust out my lung room I'm guessing.

My chimney is concrete, but the furnace is not too far from my grow. Also have a AC duct that goes through my room, but it doesnt even cool my bedroom off very well, its the weakest duct in the house for cold air flow.

Any input is appreciated!

Besides getting AC, I see this as my only option because I dont think I could run any bigger of a fan than I am now out the very small 3.5"x9" window opening.
 

mojave green

rockin in the free world
Veteran
serial fans

serial fans

what happens if i serially connect two ea 6" centrifugal fans of 400cfm ea. same make and model. pulling air from swamp cooler, connected via 6" flexible duct. no duct on exhaust.
 

sir alex

Member
air force fans????

air force fans????

hi peeps got a few questions here any info would be great...well ive been using my 2 air force acoustic 1 box fans for 2 years now and there still working just fine, my friend is setting up a large size bedroom and wanted me to let him now what to get I can only seem to find the new airforce 2 cylinder types and there quite expensive to.do you know anything about these fans and are they worth the price tag that goes with them,and is there any other companies out there that do just as good,
 
W

willyweed

try google! very broad question mr manc.need a few more details before we give out any information , like how big is the room? how many lights? ect ect ect the more details you give the better answer you will get !
 

Cereus

Active member
Hi, I need help, please.

I have DR60II and need advice which fan and carbon filter will be okay.

RVK 100mm/4" A1 Fan, Max. airflow 184 m³/h, or
RVK 125mm/5" A1 Fan, Max. airflow 220 m³/h

100MM Rhino Pro Filter, Maximum air flow rated @ 350 m³/hr, or
125MM Rhino Pro Filter, Maximum air flow rated @ 500 m³/hr.

There will be speed controler for rvk fan.

The lights will be 2x LED GN0006, cultivation of vinter, intake-air will be from outside.

Thanks.
 

Granger2

Active member
Veteran
Cereus,
Always go big with ventilation. You don't need a speed controller for the size filters you are considering. As long as the cfm of the fan is less than the cfm rating for the filter, you're OK. I googled the fans and the tent, since you didn't supply the info about these items [sigh], and you'd probably want to downspeed the fan for the size of your tent [2x2x5'4"]. Rule of thumb, exchange all air in tent at least 3 times/min. More is better within reason. Make sure you have twice the sq. inches of intake as exhaust. Good luck. -granger
 

MichGrower91

New member
hey everyone Im having a few minor issues with my venting... I have 2 8" solis max 66 hoods 2-1000w hps and my fan is an 8" canfan max! no carbon filter just normal flex ducting. its venting into the attic but I have no intake... there are 2 windows but I cant find a way to make it cool enuff(73-75 when lights are on. I have a 12000btu portable a/c but id like to keep it as low on energy bills as possible but if that is my last resort then I have to do it.
 

Budwhyser

Member
hey everyone Im having a few minor issues with my venting... I have 2 8" solis max 66 hoods 2-1000w hps and my fan is an 8" canfan max! no carbon filter just normal flex ducting. its venting into the attic but I have no intake... there are 2 windows but I cant find a way to make it cool enuff(73-75 when lights are on. I have a 12000btu portable a/c but id like to keep it as low on energy bills as possible but if that is my last resort then I have to do it.

Circulating fans can help but there is no other way to cool a room with lights on without using A/C or bringing in cooler outside air period
 

MichGrower91

New member
Circulating fans can help but there is no other way to cool a room with lights on without using A/C or bringing in cooler outside air period
I have 3 standing fans in the room and I just made a hole in the door for an intake hopefully a passive intake will help cool this room.
 

spaceboy

Active member
73-75 is about perfect if you ask me. Just try to keep your night time temp at about 70 or 72 if possible and you'll be golden.
 

gkoat

Member
Quick question for you ventilation experts...

I have 2 inline fans and I'm trying to cool a light that is in a completely enclosed reflector with 6" vents on each end. I have a soso 4" exhaust, and a badass 6" exhaust. I as well have a 6" to 4" reducer.

So what is the best way to do this? I know 2:1 is a rule of thumb for grow space but is it iany different for air that's only traveling over a bulb?

To reiterate, my setup goes something like...

fan>light>fan.....where do I put the 6" and where shoud I put the 4? Thanks in advance!
 

Jnugg

Active member
Veteran
I'd use one fan to cool the bulb

Ambient air>ducting>fan>hood>ducting to attic/window exhaust box/or another room.

Then use the other fan for ventilation of the grow...just be sure you're not dumping any of that hot air into the room the grow pulls it's fresh/cool air from,otherwise you'll constantly be raising that rooms temps,thus raising the temps in the grow.
 

gkoat

Member
I'd use one fan to cool the bulb

Ambient air>ducting>fan>hood>ducting to attic/window exhaust box/or another room.

Then use the other fan for ventilation of the grow...just be sure you're not dumping any of that hot air into the room the grow pulls it's fresh/cool air from,otherwise you'll constantly be raising that rooms temps,thus raising the temps in the grow.

You think 1 will do the trick? I'm guessing 2 would do better but not worth it in your opinion?

Which would you put the 6" on? The light or the chamber?

Thanks for input
 

Jnugg

Active member
Veteran
Stacking/connecting two fans together won't give you more airflow (especially when one is smaller than the other).

What size light and how big is the grow area?
 

gkoat

Member
Stacking/connecting two fans together won't give you more airflow (especially when one is smaller than the other).

What size light and how big is the grow area?

hmmm...i didn't know this....so there's no point in having one fan to blow onto the bulb and one to pull air away from it? I thought this was a common setup for light ventilation?

I'm working w a 4x2, currently w a 400w hps, i'd like to upgrade eventually so I'm not focused on *getting temps down* so much as I am *maximizing my ventilation*

The tent has 6" openings so any fan bigger than 6" will need to be reduced - but is a 8" inline reduced to 6" any more powerful than a 6" not-reduced?
 

Jnugg

Active member
Veteran
Try using the 6" for cooling the light and the 4" for ventilation,and vice versa and see what works best for you.
 
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