# best ventilation option?(with pics)



## Snitzel (Oct 9, 2009)

OK, so it's 2x6x8' closet that I plan on splitting into 2 sections..top for veg, bottom for flower.  There will also be fans in the shelf in the middle so the 2 halves share the air. (they'll be filtered/covered to prevent light leaks)

I'm using a 1000w HPS in a glass covered reflector for the flower half, and CFL's for the veg. I'll most likely be using 8" can max fans with 675cfm.

Im wondering if I can get away with just the 2 fans as shown in the 2nd picture:

filter inside room > fan > 1000w hps > exhaust room
with a seperate intake

or the more expensive option as shown in first picture

filter outside room > fan > 1000w hps > exhaust just the fan for the light
with a seperate intake AND exhaust


If I don't have to buy the 3rd fan i'd rather not. The ambient temps outside the room is generally 65-80f. 

So, will using the air in the same room as the light (675cfm can max fan) be enough to cool the 1000w hps AND exhaust the room?


The pictures might explain it a bit better for those that are lazy ;P


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## purplephazes (Oct 9, 2009)

Are you using 1000 hps for flower and vege do you have 2 x 1000 watters ? This makes me wonder ....Quote = I plan on splitting into 2 sections..top for veg, bottom for flower


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## Snitzel (Oct 9, 2009)

Sorry I didn't clarify, i'll be using CFL's for the veg half (mothers/clones)


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## Snitzel (Oct 10, 2009)

So what do you guys think? I'll probably be getting 8" can max fans, which are 675 cfm(although a little pricy) So buying 2 is definitely preferred... What do you think?


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## willowgrow (Oct 11, 2009)

The first design is kinds pointless. No need to be filtering air that is simply being run through ductwork to cool your lights and back out. 

If you want to stick with 2 fans/1 filter, I would have a fan pulling air through the filter/light and exhausting out for the flower section. For the veg just run a fan exhausting out; the plants won't smell skunky in veg, but you will smell that green, vegetative smell. For the intake, just cut a hole big enough to still allow for neg. Pressure = passive intake.

Also, 2 8" 675cfm fans are a little much; you could get away with something much smaller for your space.  I would also flip the rooms around, if possible (flower on top/veg bottom). The 1000w hps is going to get much hotter than your flouros, so it will make it much easier on your fan pulling air through the filter and light.


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## Snitzel (Oct 11, 2009)

wow awesome ideas, the reasoning behind the flower on the bottom was because I was planning a hydro grow and I didn't want the reservoirs to put too much weight on the shelf. I'll probably switch them though, it only makes sense too.

The passive intake isn't a bad idea, I could cover the hole on both sides with some form of a vent cover. 

If I put 2 fans in the shelf, so both halves share the same air - do you think it would be better to do what's in the 2nd picture? Which is pulling air through the light/filter out of the room - with another intake. That way I have an intake and exhaust, with a way to cool the light.


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## willowgrow (Oct 11, 2009)

I would treat your setup as 2 separate rooms, each with its own intake/exhaust.  You can put a vent on the outside of the room, and a 90 degree duct to eliminate light leaks on the inside. 

The setup in pic2 would work great for your flowering room; you are scrubbing the air w/ the filter, cooling your light, and exhausting heat with one line.  For the Veg room I would mount a fan up top (by the shelf) and run ducting through the shelf and flower room and exhaust outside of the room.  

This way each room is separate with its own passive intake/exhaust.  Good luck! Hope this helps. 
:aok:


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## SkunkPatronus (Oct 11, 2009)

Snitzel said:
			
		

> wow awesome ideas, the reasoning behind the flower on the bottom was because I was planning a hydro grow and I didn't want the reservoirs to put too much weight on the shelf. I'll probably switch them though, it only makes sense too.
> 
> The passive intake isn't a bad idea, I could cover the hole on both sides with some form of a vent cover.
> 
> If I put 2 fans in the shelf, so both halves share the same air - do you think it would be better to do what's in the 2nd picture? Which is pulling air through the light/filter out of the room - with another intake. That way I have an intake and exhaust, with a way to cool the light.


 



Just a suggestion but i think i would start with dirt... with all the learning going on about room setup and actual use, you really are going to have some headaches and major failures if you are also learning hydro growing at the same times as learning a new set up.  Even if you just do a couple of dirt runs, then switch to hydro when you and your room are fully aquainted you will be better off.


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## Snitzel (Oct 11, 2009)

willowgrow said:
			
		

> I would treat your setup as 2 separate rooms, each with its own intake/exhaust. You can put a vent on the outside of the room, and a 90 degree duct to eliminate light leaks on the inside.
> 
> The setup in pic2 would work great for your flowering room; you are scrubbing the air w/ the filter, cooling your light, and exhausting heat with one line. For the Veg room I would mount a fan up top (by the shelf) and run ducting through the shelf and flower room and exhaust outside of the room.
> 
> ...



Yeah that's a good idea - i'll do that. Do you have a recommendation as to how much CFM I might need? I was gonna, like I said, get the 8" max fans - which might be over kill, but would definitely do the job. What's killing me is the price! What I do like about them is the efficiency...i'd probably save in the long run by paying less per month in electric...what would be a good alternative? i'd be willing to get 3 or 4 fans (whatever is necessary to vent properly) at a lower price.




			
				SkunkPatronus said:
			
		

> Just a suggestion but i think i would start with dirt... with all the learning going on about room setup and actual use, you really are going to have some headaches and major failures if you are also learning hydro growing at the same times as learning a new set up.  Even if you just do a couple of dirt runs, then switch to hydro when you and your room are fully aquainted you will be better off.



yeah I thought about it until I get the hang of it...my first grow a few years back was an ebb and flow which was quite successful, i'll be doing a bubbleponics this time around, i'm pretty dead set on it 

You guys are great though, thanks a ton for helping me with this


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## willowgrow (Oct 11, 2009)

Well, rule of thumb is you want to be able to exchange the air in your room at least once a minute.  So If you break down your 2x6x8' space into two sections: 2x6x5' (flower) & 2x6x3' (veg) that gives you 60 CF & 36 CF, respectively.  

So, your basically looking for 2 fans rated above 60 CFM.. which is pretty much anything.  Like you said, it comes down to power efficiency, noise etc.  A 4" inline duct fan is rated at about 65 CFM and you can get one for about 20$ (most require that you hardwire them yourself) at Home Depot or Lowes; but that is pretty much the bare minimum.  

It all depends on what you want really.  2 60+ CFM fans is all you really NEED.  Are you planning to expand?  Is noise an issue?  HTG has some pretty good deals and a decent selection: hXXp://htgsupply.com/products.asp?categoryID=7&subcategoryID=39

:headbang2:Good Luck!:headbang2:


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## bluealein56 (Oct 12, 2009)

i have always been told that it is better to pull air across your lights rather thatn to push it across. In other words put the fan on the other side of the light. just what i been told.


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## The Hemp Goddess (Oct 12, 2009)

IMO, you are going to need a lot larger fan than 60 cfm to keep that 1000W light cool in that small a space. 

I like to exchange the air in my room 3-4 times a minute.  With a carbon filter, you are also going to need a little more power.  

The inline duct fans that you get at places like HD are generally booster fans and do not have much power on their own.  I would recommend looking minto Can or Vortex fans.  that 1000W is going to put out some heat.


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## willowgrow (Oct 12, 2009)

I have used the inline booster fans for grows in small spaces, and they do work.  I agree that a vortex or canfan is much much better, which is why I pointed to htg.  IMO, a 4" 170cfm fan is all that's necessary if you go that route, possibly a 6".  Not an 8".


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## Snitzel (Oct 12, 2009)

I'm looking at ATLEAST a vortex 6inch 449 cfm high power inline fan for $150, for the 1000w hps

is plantlightinghydroponics a good vendor? (won't let me post the link)


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## Snitzel (Oct 12, 2009)

bluealein56 said:
			
		

> i have always been told that it is better to pull air across your lights rather thatn to push it across. In other words put the fan on the other side of the light. just what i been told.



Oh and thanks, I actually did wonder about that


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## bluealein56 (Oct 13, 2009)

(won't let me post the link)[/QUOTE]

thats a good thing for us here at MP. paste the link but take out the http:// and replace.


anyways yeah the booster crap wont do anything from you. 

I would go with a can fan. I currently use a 6 inch high output can fan at 440chm for a 2x3x8 closet on a 400w hood. it keeps it cool and is way way overkill. Like big time. had to add more vents to pull air into the room cause the fan was sucking so much air out that the door was exxtrememly hard to open from all the pressure on it. 

The reason i say can fan is cause i found a few cool videos on youtube of the  can fan i currently own, vs a vortex fan of the supposed sme caliber and performance level. 
The can fna crushed the vortex in every video i watched making the vortex looking patheticaly weak. And only going on what i have read, you lose alot of power on a vortex fan when you hook it up to a carbon filter vs a can fan which doesnt lose near as much suction power when connected to a filter. Im sure others have thier fav, im just a can man


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## Snitzel (Oct 18, 2009)

So, in the flower room i'll have a 178CFM canfan exhausting and cooling the light...do you think a passive intake will be enough? or should I also get another fan for the intake?


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## Snitzel (Oct 18, 2009)

Also - I have some Dyna-Rok II, i've had it for a few years now (from past non-cannabis grows) It's only been used twice, and not even all of it. 

hXXp://xxx.gardeningwarehousedirect.com/pd_dynarok_ii.cfm

Is this a suitable growing medium? Or would you guys still recommend hydroton? I feel like it doesn't really matter that much...

What do you guys think?


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