# Airflow



## ardano75 (Dec 29, 2014)

If this is a duplicate sorry....

Setting up a 960 cu ft flower room in the basement. Need advice on the size of exhaust inline fan to swap air. Using a 1000w hps with just a wing. It's winter here so maybe the heat will stay down. Exhaust distance from room to outlet for the air is Around 15 straight shot under the house. Intake will be from the basement it's self. Also how many amps does a 1000w hps pull if wired 240. Hope someone can help. 

Thanks


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## Gman_517 (Dec 29, 2014)

I'd recommend an 8 inch inline fan


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## Hushpuppy (Dec 29, 2014)

Remember this formula: P over I x E or watts is divided by current to get voltage. Or watts divided by voltage to get current. In your case, a 1000w on 245v (actual line voltage) equals 4amps. 

If you were running an enclosed hood or cool tube fixture, I would say a 6" vortex 540cfm would do the trick but with an open fixture, all that heat is staying in the space, so you will need to really pull the air out to keep them cool. You may have to go with an 8" to get higher cfm. Normally you could get away with cycling the air in the space every few minutes max, but with the open hood, you will need to cycle that air once every minute I believe. I am giving an educated guess of course, so you will have to try it and see. 

Now how tall is the space? that will make a significant difference as heat rises.


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## ardano75 (Dec 30, 2014)

Thanks Gman and Hushpuppy. So basically right ow I need 8" fan till I can get an air cooled hood then I could switch if I wanted to, correct?  Also the height of the room will be around 7 1/2 feet tall.  Thanks for the advice y'all very helpfull


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## The Hemp Goddess (Dec 30, 2014)

I am concerned about the "using a 1000W in 960 cu ft.", way more than your exhaust.  With 960 cu ft and 7-1/2' ceilings, you are talking about a 130 sq ft.  flowering space.  A 1000W light is only good for about 28-30 sq ft...and that is pushing it to the absolute max.  I recommend that you build some kind of enclosure in a corner of your basement around 28-30 sq ft (or smaller--I run 1000W in 20 sq ft) that you can contain the light and control the environment.


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## Hushpuppy (Dec 30, 2014)

I agree with The Hemp Goddess. That is a lot of floor space. You can either build your own enclosure or buy a 4x4 tent (highly recommend iff you have the money). Also, iff you buy a 6" vortex fan rather than an 8", the money you save will just about cover the cost of a cheaper xl hooded cooltube: http://www.hpsgrowlightstore.com/ipower-grow-lights-6-cool-tube-xl-11467.html    I use these and like them very much as they throw a nice light footprint in a 4x4 space. You can connect the exhaust fan to the hood on one side with flex tube duct and connect a carbon filter to the other side of it so that you scrub the odors.

Do not get this type of fan as *they do not work*: http://www.hpsgrowlightstore.com/ipower-boosterfan-6.html
What you need is something like this: http://www.hpsgrowlightstore.com/ipower-6-inch-inline-fan-440-cfm.html
Check around on these as you may get better deals. Maybe Amazon or Ebay


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## ardano75 (Jan 1, 2015)

Thanks to everyone for the great advice. The extra floor space is for future expansion , I also I go bout 6'1" and 280 lol I'm a big guy need room to get around in. Is the room space a problem for properly air swap can the 8 oor 6 in fan not move enough air?  Also the comment about fan and filter placement does the fan attach to the fixture or filter

Thanks again everone


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## 000StankDank000 (Jan 3, 2015)

Mine goes filter fan light and out the room.  You want the run as short as possible and filter up high .


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## The Hemp Goddess (Jan 4, 2015)

ardano75 said:


> Thanks to everyone for the great advice. The extra floor space is for future expansion , I also I go bout 6'1" and 280 lol I'm a big guy need room to get around in. Is the room space a problem for properly air swap can the 8 or 6 in fan not move enough air?  Also the comment about fan and filter placement does the fan attach to the fixture or filter
> 
> Thanks again everone



I think it is important to understand why room size is so important and why you cannot just stick a light in a large space and hope for good results (it isn't going to happen).  You need your grow space to be sized according to the light you have now.  A 1000W light is only good for about 25-30 sq ft, so make your space size according to that.  I also understand needing to be able to get around, but even walking space is going to have to be accounted for as the light will disburse.  You want a minimum (and this is an absolute minimum) of 3000 lumens per sq ft for vegging and  5000 lumens per sq ft for flowering.  I cannot stress how important it is to not overextend your light.  Since most 1000W HPS put out 130-150,000 lumens, you can have a room from around 25 to 30 sq ft and NO larger.  But you need an enclosed space for more reasons than simply light dispersal, but that is one of the most important reasons. 

You also need to be able to control the environment within your space.  That includes, temperatures, humidity, and ambient light.  Neither a 6" or an 8" fan is going to be adequate for 960 sq ft, but a 6" is most likely adequate for the 25-30 sq ft your space needs to be.  

I have a very good friend about your size who used to grow.  We made movable screens from PVC and mylar (I would use panda film now as it is easier to work with) to give him more space to work.  We were in a lot smaller space though--a room about 100 sq ft that we enclosed a 4 x 7 space for growing with movable panels.      

.I hope that you understand the importance of having a space designed to the light you are going to be using, which is more important than the size of fan you need to buy.  I can pretty much guarantee you that a 1000W light in a 960 sq ft space is going to give you really poor results.  An enclosure is essential.  If you are not "handy" enough to build something, I would encourage you to look into getting a tent designed for growing.


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