Need help finding fans

Discussion in 'Growing Marijuana Indoors' started by disorder80d, Jun 7, 2009.

1. Hi guys, im settin up my flower chamber right now, its gonna have a 600watt hps light in it. i want to have a good ventilation system set up for it, does anyone have a link or reference to a page with good fans or possible techniques for setting up a vent system. any help would be great.

-Disorder

2. Check into cooltubes or vented reflector hoods. 600W gets hot, and you'll need to

~Experimentalist

3. Figure out the cubic area of your room Length x Width x Height (in feet) and multiply that time 1.6
That will be the number of cubic feet per minute or CFM you need for a fan. For example an 8ft by 8ft room with a ceiling height of 8 ft is 8x8x8 =512 multiply by 1.6 and you would need a fan that puts out about 800 CFM. Of course when you're pulling out 800 CFMs out of a room, you will need to make provisions to bring that much fresh air back in.

keylime

4. That is wrong. Take the 8x8x8 and DIVIDE by 5, that number is the required CFM.

~Experimentalist

5. Well, you may have your formula, and it may work for you, but if you think 100 CFM fan will ventilate a room that size, we are somehow not talking apples to apples. I'm a brother of yours, and I've been in the HVAC (heating ventilation, air conditioning) biz for some 10 yrs. Does that count for anything?

keylime

6. Hi..

While I won't get into the calculation debate of the previous posters, I will recommend using HTGSupply.com as an online source for ventilation setups. There have some filter/fan combinations that are reasonbable priced.

Good Luck

7. Yeah it most certainly does. Can you explain your formula for me? I don't want to be
using the wrong information, ya know? I'm just going off of what I read elsewhere.

Thanks!

~Experimentalist

8. #8
Last edited by a moderator: Jun 8, 2009
Assuming you want to exchange air 5 times per minute, multiply cubic feet of the space by 5 to get the CFM (cublic feet per minute) needed.

512 cu ft. x 5 = 2560 cfm

Just change the 5 to however many times you want to exchange air per min. Obviously 5x would be a lofty goal.

9. Yeah I am under the impression that you need to treat the air once every 5 minutes to
achieve odor-free status. Anything more than that is just luxury.

~Experimentalist

10. #10
Last edited by a moderator: Jun 9, 2009
I've designed and installed a ventilation system for a room that is 28'x8' by 7' high for a friend about 3 yrs ago. That works out 1568 CFM. He put a 1000CFM exhaust fan attached to a charcoal scrubber. He is now in re-doing the room and tells me he wants to double the exhaust system he has now. So he will have TWO 1000CFM fans exhausting. I will add, that the same fan also picks up the vented lights (5) after the air has been scrubbed and exhausts out

You say treating the air for odor free status, and you may be right in that, BUT you are not taking into consideration the fact that the girls need plenty of CO2, nor are you taking into consideration the amount of CFM taken up thru things like bug screens and charcoal filters, nor do you make any consideration for temperature treatment. The room I designed has 6 1000W lamps in it. Yes the lights are vented, but still resonate heat. 6000 watts of light generate 18,000 BTUs of heat. I'm not sure if you know how much that is, but there are gas fireplaces that will put that out heating a small home for main heat. Can you imagine placing a gas fireplace in your growroom turning it on full blast on a hot July summer day with lights on and using your calculation? I don't think the plants would last one day. This heat must also be exhausted for plants to thrive.

Proper ventilation is more than just removing stinky air!