ventilation

Can i use the fans out of a hood range that goes over a stove to ventilate my box?My box is 3x3 wide and 4 ft. high.Any help would be appreciated.Thanks

The general rule here is you want to exchange the total amount of air in your grow space once every five minutes. Here, you are working with 36 cubic feet of space. Since your space is so small, you should probably move the air more than once a minute, so we'll pick an arbitrary number of 5. 36 x 5 = 180 cfm. Therefore, you want a fan capable of moving 180cfm. Does your range hood do this? Also, how loud is the fan in question? Is stealth an issue for you? These are all things which need to be considered when building a small grow cab.

But a 100CFM fan isn't guaranteed to pull/push 100 CFM outside of free-air. Not all fans are created equal. Static pressure, ducting length & bends, plays a roll.

This is true, which is why I mentioned the factor of 5 here. That way, it gives him a little bit of insurance with respect to air movement. Removing the air in a space 3-5 times per minute will be a great help with respect to internal temperatures.

Fan style choice can drastically change the CFM rating.

Those $25 250 CFM axial duct booster fans at home cheapo are worthless.

I have one. Useless for anything grow related other then a 'booster fan as its stated. Needs a real fan upstream.

Using a S&P TD-150 on slow speed cooling *only* a 400W HPS hood. I can keep my hand on the glass without even noticing. Room stays at 78F with house at 73F (doors closed, no vent to speak about)

Squirrel cage/blower are the best for pushing air.

I agree, those axial boosters are worthless. They trick you by saying they are 250 cfm, when in fact they are only rated for 125 cfm on their own, but can boost airflow to 250 cfm in an already existing airflow situation.

Hi Everyone,

need advice. I've a 12 x12 grow space with 4 1000 hps with a cam filter exhausting 475cfm. I have an exhaust hole of 6'' and an intake hole passive and also with small fan of 6''. I can't lower the temperature of the room. It remains at 31o C which is much to high. Grow space is 12 x 12 x7 1008 cubic foot . WHAT TO DO. Do I make the passive hole bigger or do I change the cam filter to a higher capacity . Or do I increase the fan capacity in the passive intake hole. NEED ADVICE
THANKS GALVESTON

Remove the fan from the intake. It is not passive if their is a fan in the intake. That should make a huge difference.

JohnnyPotSeed1969 said:

Remove the fan from the intake. It is not passive if their is a fan in the intake. That should make a huge difference.

Click to expand...

thanks alot for the info will try and let you know

galveston

I've taken the small fan down and let the cediling hole passive. It did help but not enough to make a markable diference. I punched in another hole on the other side. Warming up is much slower but i am still not in control. My carbon filter was about 7 feet from the pulling fan so I changed that and put the fan rigfht on the carbon filter can 66. It seems and does pull more but i am not convinced that i am in control. When we hit 25of outside than i should be ok but when april comes with 40's i am in trouble. I am debating about installing a fan with same cfm as cam 66 ,475 cfm to pull in air or go passive and keep adding holes in the ceiling untill i can bring the temperature down to 80o in any circumstance. any idea's.?? The ultimate is lamps that are air cooled, but thats next years project if all goes well.
galveston

TO JOHNNY POTSEED FROM GALVESTON
JOHNNY.... SOMETHING ISN'T RIGHT IN MY SET UP AND I CAN'T PUT THE FINGURE ON IT. I'VE GOT 4 PASSIVE HOLES SIZE 8X8 IN THE CEILING AND MY CAM 66 475CFM IS SUPPOSE TO EVACUATE THE AIR. IT'S 32o OUTSIDE THE 4 1000 HPS ARE KEEPING THE TEMPERATURE AS FOLLOWS.... UP HIGH WHERE THE LIGHTS ARE AT THE 6FT LEVEL ITS 93o AT THE FLOOR LEVEL I GET 87o I HAVE 2 OSCILATING FANS IN THE MIX.WHEN I LOWER THE LIGHTS THE BOTTOM HITS 98o SO I'M NOT IN CONTROL AT ALL I WANT TO BE ABLE TO MAIN TAIN 83 TO 88 DEGREES AT PLANT LEVEL. I HAVE SEVERAL OPTIONS BUT DON'T KNOW WHICH IS BEST AND I WOULD APPRECIATE YOUR IMPUT.

I CAN ADD SMALL FANS TO THE 4 PASSIVE HOLES OR I CAN USE VORTEX FANS AND GET THE COLD AIR FROM THE FLOOR INSTEAD OF CEILING. MAYBE BECAUSE HOT AIR RISES THE TEMPERATURE BETWEEN THE ATIC AND THE ROOF IS TO WARM TO HAVE A REAL AFFECT BUT FROM THE FLOOR BLOWIN IN IT WOULD BE 32o.

I CAN CHANGE THE AIR FILTERING OUTPUT CAM 66 AND GO MUCH BIGGER. DON'T KNOW IF THAT WILL CHANGE ANYTHING I'VE GOT NO EXPERIENCE WITH THAT.

NOW THE ROOM SIZE TOTAL WITH THE GROW AREA IS 15 X 12 X7 WHICH GIVES 1260 SQUARE FEET WITH A GROW AREA OF 1000 SQUARE FOOT.

WHAT'S YOUR TAKE OR SUGGESTION ? THANKS GALVESTON