how many cfm for a 12 x 12 3200 watt room? woot

[Dank Sinatra]

Hello,

so i have a room that is 12 x 12 and i have managed to shove two 1kw hps and two 600w hps in that space for a total of 3200 watts.

I am choosing a fan right now and running out to the hydro store tomorrow to scoop it up, but i need a little advice as this is my first vertical grow, (third grow in total).

My external temps during lights on should never top 80 and should be more consistently in the 60-70 range, colorado night times : )

i have been looking at the Max-Fan line because a friend of mine loves his, but i am not sure if thats reall what right for me. The fan will have to draw air through 25 feet of straight ducting, but thats it.

So the question is how many cfm should i get for this application.
thanks for all your help.

 

[mg75]

I was recently at a stadium grow and the lights were hung in cooltubes and a 6" CanFan was pulling air up through them. Each stack of two 600 HPS had a dedicated fan on top. It basically acted as a room exhaust which past through the lights and into a lung room.
There was an 8" CanFan bringing air into the stadium.
Temps were at 80F consistent.

I can see that room needing an A/C in a month or two.

Take care of your HVAC and ventilation BEFORE you put live plants in. Do a dry test run with all the lights, fans, pumps, etc on full blast. Thats the best way to know before you risk overheating (usually).

good luck!

 

[Dank Sinatra]

yea, well i dont have heat problems now, its in two months when things warm up that i am a preparing for. Thanks though

 

[mg75]

The above room mentioned had 3000 watts and was going to add another 600hps for a total of 3600watts. To clarify... 2 6" CanFans were exhausting 3000watt HPS.

 

[Dank Sinatra]

thank you, what were the outside temps at the time, because my max fan will definitely out pull those two fans. Definitely sounding promising...

Can anyone else chime in with some of their experience?

 

[mg75]

thank you, what were the outside temps at the time, because my max fan will definitely out pull those two fans. Definitely sounding promising...

Can anyone else chime in with some of their experience?

Mid 30s F
It's winter here...

 

[humble1]

how tall is the ceiling?

length x width x height = volume (cubic feet)

with the volume it's easier to figure out what cfm you need.

Just guessing I'd say a minimum of a 10" MAX fan.
I'd get a vortex 12" XL and slow it down with a speed controller and/or smart thermostat.
It's nice to have the extra cfm if you need it!

 

[Vindie$el]

I like to use about 500 cfm per 1k of HID lighting in a normal room so you need a fan that performs about 1500cfm. Another formula I like to use as a base is 5000 BTU per 1K in a normal room. I use a 900 cfm fan that runs 24-7 and a 9000 BTU A/C on the other side of my room. The A/C comes on after the lights have been on for at least 2-3 hours and then it runs off and on until the lights go out and my room stays perfect. I have 4 1000 watts in a 12X12 room and Ilive in a hot and humid climate

 

[Dank Sinatra]

Mid 30s F
It's winter here...

well jesus man i said i was talking about 60-70s hahahahaha


humble- its about 6 feet tall

 

[Dank Sinatra]

so thats 864 CFM, sorry i was a little to high last night to do the calculations, lol. Multiplication is difficult at that level.

so if i have a max fan 10" that would exhaust my room like once a minute, thats a lot of fuckin exhaust, i read somewhere to do it once every three minutes..... but i am getting a phaeson fan speed controller so i guess it aint no thing.

That vortex 12xl is tight but a little pricey.

 

[humble1]

with a 6 foot ceiling a 10 MAX sounds perfect!
once a minute isn't too much exhaust and once every three minutes is a minimum, not an average. regardless, your exhaust should be dictated more by your temps and humidity than anything else.
what about intake?

 

[turbolaser4528]

agrreed. yeah passive or active intake?


which do you guys reccomend? Ive always gone passive but I suspect you can get a lot more airflow, and therefore more CO2 + 02, with properly sized active intake bringing in fresh air.


or course room conditions regulate this as well, cant have an 8" fan on full blast intaking 20 degree air!!!!

i wonder how we could remedy that....O hook up a humidistat to the intake and exhaust fans, o yeah duhh loll some1 aready mentioned it.


As an aside: I know Heath Robison is hittin 2+gpw with NO CO2 and believes that massive fresh air intake/exhaust is just as good/better so he doesn't bother with it anymore. I think he's onto something here......


take care guys god bless stay safe stay strong!!!!!

 

[Dank Sinatra]

i looked for heath robinson and he didnt have any post talking about no 2 gpw, wheres it at i wanna read

 

[Dank Sinatra]

Tight, i bought the 10" max fan today and seriously that thing is a fucking beast. Ill let yall know how it handles the room after i get everything up this weekend.

thanks

 

[humble1]

heath also has a crazy DIY vertical system and oodles of time to build and fidget.

 

[turbolaser4528]

http://www.rollitup.org/hydroponics-aeroponics/149998-heaths-flooded-tube-vertical.html

its in there somewhere, either way i know that he believes in high volume of air exhange and it makes sense, rapidly replenishing the air is recreating a breeze in nature supplying the plants with as much o2 and co2 as they need imho.

 

[Dank Sinatra]

oh its on rollit up, thats why i was confused. thanks. I also had a good friend who tends to aggree with him in the high cfm dealy so well see

 

[ZenArcade]

Tight, i bought the 10" max fan today and seriously that thing is a fucking beast. Ill let yall know how it handles the room after i get everything up this weekend.

thanks

I have been thinking about a 10" max fan. How do you like it? have you ever used one of CF's other fans (the ones they sell as a combo with the filter)? I know when they first came out with the max fan the cord wasn't grounded, just a two prong, are they still built this way?
thanks!