I am doing this in my basement. My room is 20' long by 8' wide by 9' tall. I will use 4 / 1000 watt lights and exhaust the light heat directly into my homes ductwork.. Its a 3 story home with a basement and it stays cool in the summer down there and relatively moderate in severe winter times. 8' high concrete walls for 3/4 of the basement. I plan on haveing a 8" carbon scrubber [with 700cfm internal fan] exhaust into a 8" duct that will be installed at ceiling level at of the center of the length of the room with a couple of 45 degree bends to exhaust the air, all in rigid metal duct to get out of the basement and then the 8" rigid metal duct work goes up another 20' thru the garage attic up to and thru the roof. For the intake air i plan on using 8" rigid metal duct paralell to the exhaust but going down to the opposite wall and down low to the floor, comming from the attic but at lease 12' away from the exhaust penatration thru the roof. Will this be good enough to exchange the air in the room every 4 minutes asuming the intake is passive? And if more fans are needed where would you suggest they be?
Jk, I'm a noob and planning on setting up a closet grow, 1 or 2 plants, in my basement, still trying to figure out how to vent properly, worried bout humidity myself but did I read you're planning on pulling intake air from the attic ? Don't know for sure but wouldn't your room need be sealed up real good to create neg press or pusher fans ?? Wonder bout air intake temps hot summer cold winter ? Comments because is option I hadn't considered best wishes Sent from my Nexus 5 using Grasscity Forum mobile app
OP with that long of ducting regardless of rigidity you may want todo consider an in line booster fan about midway thru your duct work. If I understand right you're asking if a 700cfm fan will exchange the air in your 1400 cf room... In theory yes it will do so every two minutes without any resistance such as duct work, turns and filters. There are a few awesome threads around here that give you the math formula for factoring those variables in to determine the effect in overall cfm of your fan. Hope it helps. All in all I would say tour 700cfm fan would be sufficient. However considering that your intake will be passive, I highly recommend having your opening at least twice the size of your exhaust. 8" exhaust would require at minimum a 16" opening. Maybe slightly larger even. Youll reduce resistance for your exhaust fan, allow easier air exchange, and still be able to achieve negative pressure withing your room. Do your self a favor and do the math. If using a carbon filter....factor it in, account for ever foot if duct work and all bends...and you'll have a concrete answer. Sent from my DROIDX using Grasscity Forum mobile app