desired CFM for 4'X4'X7' w/ 400 watt?

[AmazingBlazing]

well the title pretty much sums up my question. For a room that is 4 feet by 4 feet by 7 feet and runs 400 watts of lighting, what would be the desired CFM?

[Dimebonic333]

ive been trying to figure out an estimate on how much ventilation I should use with the same dimensions with 1000+ watts. Hydrohut right?

[bob bobbinson]

I have a 4Lx2Wx6H cab. I have a 265cfm squirl cage. and a can fan 33 i believe with the carbon filter.

Basically 4x2x7=108 cubic ft
265cfm = fan can move 265cubic foot per 60 seconds.

So im my cab, im exausting the room almost 3 times every min.

Ideal I think is to just move the clear the room of the stale air once every 60 secs. But im sure Ideal is relative.

So anyhow, using the info above you can see what u need :} remember exausting more hot air = cooler temps.

[GaGrown]

Yo bobbinson.You even have sum fan to spare.Or a bit more cfm's,for the area.You could use that exact set with reostat switch and save a bit.But you are right on track!

Ga Grown

[OmegaVermelho]

I have a 4Lx2Wx6H cab. I have a 265cfm squirl cage. and a can fan 33 i believe with the carbon filter.

Basically 4x2x7=108 cubic ft
265cfm = fan can move 265cubic foot per 60 seconds.

So im my cab, im exausting the room almost 3 times every min.

Ideal I think is to just move the clear the room of the stale air once every 60 secs. But im sure Ideal is relative.

So anyhow, using the info above you can see what u need :} remember exausting more hot air = cooler temps.

Dude i think ur math is wrong....4Lx2Wx6H=48 cubic foot not 108.....

[bob bobbinson]

Dude i think ur math is wrong....4Lx2Wx6H=48 cubic foot not 108.....


yup... ur right. see what the weed does to u. :rasta:



GAGROWN .... YA I have a thermostat switch. but I dont use it. I leave fans running all day. I like overdoing it on the CFM. because I have such a great negative pressure thing going on in my box... nothing escapes. That carbon filter is almost sucking my poly walls in a bit :P

[GaGrown]

Not a thermostat switch. A reostat switch is kinda like a dimmer switch.Except it speeds or slows the fan,or fans.You need to put a fabric relief damper to settle that negative pressure and to get that extra co2 from the active or should I say passive airflow,the plants love.
Ga Grown

[OmegaVermelho]

Not my intention to hyjack ur thread AmazingBlazing, but since my room dimensions are almost identical (4x5x6) and i also use a 400w hps, i take this chance to ask if having an extraction fan is really important considering that my growspace is part of a toolshed that doesnt heat up that much and the doors are opened frequently????And i will have a fan inside do move the air (just to simulate wind conditions)..once again sorry to step in AB....

[bob bobbinson]

GaGrown

Ahhh thats what that is. Ive read though that they do not work with squirlcage fans. Something about those fans arent made to have the current altered. The can fan i read, is ok with one.

Fabric dampner... hmm never heard of this. what does it do?

CO2.. being my first grow, i wasent really attempting to maximize co2. But if that fabric dampner thingy does something to help let me know :thumbsup:

[latewood]

the only negative to running your fans too much...Is you don't allow the naturally available co2 to be used by your plants...It is better to use a thermostat or run fan 5 minutes once an hour or as many times as necessary to keep temps within optimum range.

lw

[GaGrown]

the fabric relief damper is something you use to release negative pressure.At the same time it can be used in conjunction with a fan to pull fresh air in and refresh the depleted air with outside c02.It needs to be positioned low in the room,and you fan up high.Not too close together,though! It's called passive airflow!

Ga Grown

[Jdog7000]

I'm planning on using a hepafilter over a hole somewhere.
Atach a duct to it.
And run it to the floor.
That way the negitive pressure will suck the fresh air in from OUtside or another room.
We'll see how the place is built.

[GaGrown]

Jdog your right on the money!

Holla!
Ga Grown

[GaGrown]

lemme add this.The hepa filter will restrict the airflow some what.It takes alot of air to build negative pressure.so to make your passive air work in order to recieve some of that precious c02 from outside air,your gonna have to use a filter that is less restrictive! Hows that for grammar?

Holla!
Ga Grown