I use two 20" basic $10 box fans for each room, flower and veg. I cut 2 holes in the cieling of my 8' tall closet on opposite ends, so they are roughly 5 feet apart. One blows cool air down the side of my room, while the other, in an alcove/shelf higher up on the other side pulls my hot air out- I leave my ballast in my grow room, because it is directly under the outtake fan, and it's more discreet than having cables and such coming out of your closet. My closet does hum with 4 box fans on med speed, moving about 100 cfm each, but it's only noticeable, becuase I know it's there. The average house guest would not be able to hear it I don't think. So plenty of ventilation here.
I did have to slightly modify a couple of strategic holes in my dry wall, some small electrical splicing, and install a gfci switch to double my bases. But with my doors closed, temps are down to a managable 75% consistantly with 25% humidity. I have some smaller fans mounted in opposing corners about 1 foot up the wall to simulate natural breeze, and promote thicker stem developement. All and all I'm quite impressed with how this set up works. You can check my grow journal in my sig, and I apologize for the crappy cell phone quality pics.
One of the main reasons this works for me, is I have a a secondary closet space on top of my regular closet. So, I'm using this space as an air exchanger/cooling bay, before the hot vented out air gets pulled back in again. Granted I'm not using alot of heat atm- 1 400watt MH with no glass shield or air cooling, but it's doing quite nicely. I may add another 400 watt MH in this room or use my alcove for cuttings/clones, or fresh seedlings under compact floro's-
Now that my veggies are nearing 4-5 weeks, I'm installing a 1000 watt HPS light in the flowering room- This hood will have to be air cooled of course, but the flanges I was looking at are 6" big !
https://www.htgsupply.com/growlights.asp?categoryID=1&subcategoryID=3&typeID=53
So my question now it, what exactly do I mount to 6" flex tubing? some sort of squirel cage fan, or? I'll need 2 obviously, one on each end- And I'll probably just vent them directly out of my closet instead of the extra closet on top.
What Kind of fan am I looking for here and what kind of cfm pull/push is sufficient to cool a 1000w HPS bulb/hood?
to produce the most air movement, to oscillate or not, at what level is it best to have the air circulation blow on the plants, + how best to mount the fan - wall / floor / hanging from the ceiling, etc., any/all info. involving fans would be helpful. i currently have 5 fans running (2 directly blowing on ballast, 3 trying to move air around, but i'm not overly pleased with the results)
