I have a room that is approx 11X12 and need to figure out two things. 1. How many CFM's do I need? I have the choice of 1080cfm, 780cf,, and 440 cfm. 2. How loud are these fans? The bedroom is on the front corner of the house. Will people hear it outside? If someone is standing in the hallway, will they hear it through the door and walls? Thanks, I appreciate the help.
Go as big as you can. I have a 4" in a 4x4x8 closet and wish i had more. It's pulling through a scrubber and the ducting is to long with too many bends in it, so I might be able to improve it some, but I'm still figuring it all out. All the noise is going to come at the end of the line. Mine is running through a dryer vent and puts me to sleep at night. Sounds like a window air conditioner. Eventually I'd like to run 4" duct threw the wall into a big fat insulated exhaust that is inside of a cabinet outside the grow to seep out of. I think that would be pretty stealth. Hope that helps some. EDIT: If you hang your fan from bungie cords there is absolutely no vibration noise from the fan itself.