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Tutorial Ventilation 101

Jellyfish

Invertebrata Inebriata
Veteran
I exhaust to my basement and it doesn't really hurt the A/C all that much in the summer. But, it makes a good bit of difference in the winter! :biggrin:

Do you mean it contributes to the heat and reduces your heat bill? Am I understanding that? Also, if you exhaust to your basement, does that mean you have to keep your basement private/secure?

Thanks! Great thread, still!
 

Snook

Still Learning
Do you mean it contributes to the heat and reduces your heat bill? Am I understanding that? Also, if you exhaust to your basement, does that mean you have to keep your basement private/secure?

Thanks! Great thread, still!

without filters, yes. and that smell will aromize (new word) the upstairs too. I vent to the attic and let the volume of the attic air dilute the smell that exits thru the ridge vent in the roof during the day and the eave vents at night house still smells some, a ozone generator by the front door helps so 'company' isn't hit in the face with the smell immediately.
 
Plan you vent two tents with one fan pulling through a scrubber in one tent while creating a passive intake from the other tent?
I am asking because I just setup the htg supply stackable tents and I am trying to figure out my vent method. I want to vent both tents through one fan and scrubber. I was thinking of running duct out of the side of the tent above into the lower grow tent which would be vented by pulling through a scrubber then a fan. I was wondering if I would be able to create enough negative pressure in the top tent to maintain smell. The top small tent is basically going to be my mother/early first 3 weeks veg cab. And the bottom tent would be an extra veg week and 2 week flower.
 

messn'n'gommin'

ember
Veteran
Do you mean it contributes to the heat and reduces your heat bill? Am I understanding that? Also, if you exhaust to your basement, does that mean you have to keep your basement private/secure?

Thanks! Great thread, still!

Firstly, my apologies for taking so long to respond. I've gotten lazy the past few years (lol...read: old!) and have been slow to sign in, very often.

Yeah! Closet air is filtered before exhausting to an unfinished basement. There are cosmetic differences from these old pic's, but, essentially the same setup.



It does help in the winter, but hurts in the summer. Even then, that's all relative, as it isn't a real big difference either season, though. I just couldn't justify the extra expense of drawing conditioned air from inside and exhausting it outside. Still, I'm lucky, for some, dumping to the outside or attic is the only real option!
 

messn'n'gommin'

ember
Veteran
Plan you vent two tents with one fan pulling through a scrubber in one tent while creating a passive intake from the other tent?
I am asking because I just setup the htg supply stackable tents and I am trying to figure out my vent method. I want to vent both tents through one fan and scrubber. I was thinking of running duct out of the side of the tent above into the lower grow tent which would be vented by pulling through a scrubber then a fan. I was wondering if I would be able to create enough negative pressure in the top tent to maintain smell. The top small tent is basically going to be my mother/early first 3 weeks veg cab. And the bottom tent would be an extra veg week and 2 week flower.

Although it takes nothing else into consideration (i.e. anything and everything that contributes to resistance), this is a good guide to go by. A good guesstimate for the size of fan: figure what you'll need, add 10%, then pick the closest larger volume fan you can find.


Probably the easiest way is to vent each 600 into one 6" to 8" wye you mentioned earlier. An 8" fan/filter should take care of it. You could also install a filter in each tent before drawing air from them. As for venting outside I wouldn't know if it was cheaper to exhaust to the outside or recirculate the room air through the tents and use a window banger to cool the room temps. All things considered, you're essentially running a 1200w space heater 12 hours a day, minimum.

Your veg tent can have a considerably smaller fan, but I won't say you won't have to filter the air. I'm told that some varieties in veg can pump out the aroma, as much as some other varieties in flowering! But, that's a judgement call only you can make.
 
Thanks for the response.
As far as the grow tents I was talking about earlier, I will be extracting each with there own 6 inch vortex into the room itself and when I get around to cooling my light come May or maybe sooner I will run a sealed 4" wind tunnel fan in between the tents to draw the heat from the lights and exhaust to a window. I am only running one 600w per 12hr cycle so should be enough air flow.
As for my other situation it's is actually a different tent all together, these two are going to be my mother/early veg tent and the other a veg to flower transition tent.
The mother/ veg tent is on the top, it is 1mx1mx1m. It is housing two 2 bulb tek flours lamps.
The base tent which is about 5 ft tall will be housing a 400w CMH.
What I wanted to do was run a duct from a 6inch hole on the top tent to the bottom tent,
Then I was going to install my fan filter combo in that tent (completely separate from the ducting of the top tent) and create hopefully enough pressure to draw the air from the top tent out as well as the bottom. I have a vortex s 6 incher to hopefully do this.
 

messn'n'gommin'

ember
Veteran
A closed circuit for your lights is even better! It will still get somewhat warmer in the room, but, that won't be too large an obstacle to overcome!

From the way I understand your setup, I think you have things well in hand! :)

Peace!
 
I have the dual tent system running and it is perfect. still havent AC the light yet. Not sure how I am going to go about it. I want to run it carbon filter, Light, Fan, Muffler but I dont want to have to many degrees of bend. I might configure it in more of a straight S shape. Carbon filter front to back right corner closest, Light horizontal center, Fan upper left corner front to back, Muffler back right horizontal. The Vortex S 500 are only like 350cfm, dont want to lose too much to ducting.
 

loving_weed

New member
Hello, very nice thread indeed! I have a question regarding my setup, for which i would be very pleased if i got an answer!

Grow Tent: 7'x7'x7'

Lights
: 2400w in cooltubes (4x600w, 1200w vertical, 1200w horizontal)

Fans used for cooltubes:

1x400 CFM exhaust fan for the two horizontal cooltubes with 15 feet of ducting in total bringing 55F air from outside.

1x200 CFM exhaust fan for one vertical cooltube with 10 feet of ducting in total bringing 75F air from the room i have my tent sitting.

1x150 CFM cheap booster fan with 5 feet of ducting in total for the other vertical cooltube bringing 55 F air from outside.


Fans used for exhaust
:

1x400 CFM exhaust fan (6 inches diameter) with 7 feet of ducting in total pulling through carbon filter.

1x150 CFM exhaust fan (5 inches diameter) with 6 feet of ducting in total pulling through carbon filter.

2x200 CFM exhaust fans (5 inches diameter each) with 6 feet of ducting pulling through carbon filters.


Intake:

Passive, having 2x6 inches of ducting for the 400 CFM 6 inch fan. Also having 6x5 inch ducting for the 3x5 inch exhaust fans.

The length of each ducting is 2.5 feet.

Still, while the intake air coming to the grow tent is 55F, the thermometer in the middle of my grow tent reads 82 F. And we are still in the winter here! I cant imagine what will happen in spring.

Any ideas of what's going wrong? I would like some suggestions, thank you!

I have also created a thread called "Cooling grow tent?" in this section for more details. I know i have written a lot and i make most of you bored to death, but it was the only way i knew to let you know my problem. A problem which costs me everyday as i am growing autoflowers.
 

soundnuker

New member
I'm making a filter with activated carbon(bought from pet store, the one for fish tanks)

Going to use this to hold the carbon, it's 2 inches thick and about 1 inch right in the center. I made with a fruit can and the net is from a colander.

The problem is there is no airflow through it, I even blew really hard on it and there's no movement at all.

Also, I am thinking of using cotton rolls between 2 layers of aluminum net. just tried blowing through the cotton rolls and very little air flow.



sorry for the shitty pics, all I can do.
 

Zarezhu

Member
Hey guys, I'd really appreciate some insight. I tried to find formulas to calculate exactly what I need, but quickly got overwhelmed and am hoping to find somebody with previous experience in a similar situation.

I have a 12 x 12 x 8 shed (1152 sq feet) shed out back, its insulated with 1/2" rigid foam.
There are going to be either 4kw or 5kw of lights in there.
I have one 12" inline fan (1050 cfm) that I'm going to mount on the top of one of the walls, and on the opposite wall I'm going to have passive intakes(just regular 24" filters).
The lights will be "on" from 8PM to 8AM. The average night time weather for the next 3 months should be roughly 45-65.

Will a single 12" fan be able to keep temperatures under 80 degrees with 5kw burning and with intake temperatures at 65 degrees and fresh air exchange at just over once a minute?

If not, I can add a second large extraction fan, but I've read that much air movement will cause wind burn to the plants.

Another option, more expensive, is to buy all digital dimmable ballasts. On the hotter days, turn all ballasts to 750 or 600w.

But most importantly, will the single 12" work to keep 5kw of magnetic ballasts/open bulb reflectors cool enough on a 65 degree night?
 

Psuper

Member
PLEASE HELP

PLEASE HELP

I could really use some insight regarding a new setup I am putting together---

Venting/scrubbing air from a 3'x3' tent with a 600 watt digital ballast with air-cooled reflector. Using a 6" inline with speed controller.

I hear mixed things about pulling hot air through the fan. Ideally I would like the inline fan outside of the tent.

How do I tell if there is excessive heat being pulled through my inline fan?
 

mojave green

rockin in the free world
Veteran
I could really use some insight regarding a new setup I am putting together---

Venting/scrubbing air from a 3'x3' tent with a 600 watt digital ballast with air-cooled reflector. Using a 6" inline with speed controller.

I hear mixed things about pulling hot air through the fan. Ideally I would like the inline fan outside of the tent.

How do I tell if there is excessive heat being pulled through my inline fan?
i am unaware of a method of exhausting 'hot' air that does not pull 'hot' air through the fan being used to exhaust that 'hot' air.
no way around it friend.
:tiphat:
 

Snook

Still Learning
I could really use some insight regarding a new setup I am putting together---

Venting/scrubbing air from a 3'x3' tent with a 600 watt digital ballast with air-cooled reflector. Using a 6" inline with speed controller.

I hear mixed things about pulling hot air through the fan. Ideally I would like the inline fan outside of the tent.

How do I tell if there is excessive heat being pulled through my inline fan?
something like this will help: http://www.harborfreight.com/non-contact-infrared-thermometer-with-laser-targeting-69465-8905.html

I pull thru, the fan has been in place for 2 years..dono.

where is your tent? attic? basement? bedroom? ambient temps? RH? do you have intake little doors opened enough/too much?
 

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