Fan Help- CFM Q's

I have a 4x4 grow room with a 600w HPS and 2 150w MH's (mounted on the wall at the top at 45degree angles to expose more plant surface to light). The 600w has a tube cooled hood that i will be venting with a inline fan and some ducting. The room will also have a secondary heat exhaust at the top with a carbon filter for the smell.

My question is would it be better to use my high rated fan (240 cfm) to cool the 600 w light tube and my 100 cfm fan to cool the room? Would a lower cfm fan in the tube be effective? would 240 cfm be too much for the 4x4x7 room? Thanks guys!

Once again
How would i maximize cooling with a 100 and 240 cfm rated fan between a tube cooling system and a hot air exhaust for the room itself.

lastly... is this a guy sleeping, or a guy with a mutant snake arm growing out of his head.

Im guessing the 240 cfm is an actual inline and the 100 cfm a duct booster?

Your setup should resemble this: Carbonfilter inside your room > 240cfm fan > ducting > cooltube > ducting to outside of the room (the fan can really go anywhere in the chain). This way all air leaving the room is filtered, your light is cooled with clean air, and all hot filtered air is removed. The suction of the 240cfm fan will create enough of a vacuum to pull in fresh air. 240cfm is not too much for a 4x4x7' room.

Duct booster fans rarely have enough suction to pull efficiently through a carbon filter. With such a small grow area the 100cfm fan shouldn't be necessary at all.

if the fan venting the cool tube vents into the room i would use the smaller one on the cool tube and the bigger one on your carbon filter. for one the carbon filter fan is going to have some resistance pulling through that filter so may want the bigger fan for that.

no expert just what i would do.

Thx for the feedback. Could I set it up with ducting >240 cfm fan> carbon filter on the outside for the hot air exhaust and separate intake from left of the room>ducting> cooling tube/light> ducting> duct booster to exterior. That way the light is being cooled with the coldest possible air(directly from my cold attic) and being vented directly outside. I am just concerned with the carbon filter being inside with the high humidity I aim to keep. I don't want mildew or mold growing on the spongy fabric.

I use a 600w air cooled hood with its own cool air intake and a seperate fan filter combo for scrubbing the air.

My 600w uses a 400cfm centrifugal fan.

My exhaust uses 200cfm centrifugal fan.

Duct booster fans are garbage at cooling and will not adaquately cool a 600w.





J

jondamon said:

I use a 600w air cooled hood with its own cool air intake and a seperate fan filter combo for scrubbing the air.

My 600w uses a 400cfm centrifugal fan.

My exhaust uses 200cfm centrifugal fan.

Duct booster fans are garbage at cooling and will not adaquately cool a 600w.

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I have a 240cfm duct booster fan cooling my 600w and it's so cool I can leave my hand on the reflector glass and metal without getting burned. The 100cfm may not work as efficiently.

4x4x7=112 cubic feet. I wouldn't use the 100cfm for the room.

So for a 240 CFM fan you're getting 2 air changes a minute, not bad. But you have a carbon filter on it, which the fan needs to overcome the great deal of static pressure the fan creates. Long duct runs would also increase static pressure. Axial fans are very poor for high static pressures. If your fan is axial look towards using the 240cfm for the light and get a centrifugal or mixed flow inline for the filter and room exhaust.

Room exhaust is one of the few things in a grow room where more is better. Especially if you get a fan with multiple speed settings, get an oversized fan and put it on low, better for noise problems.

THx for the feedback firsttimeare. I guess I just gotta call Saul.