hmmm, well, my duct fan specifically instructs to use it ONLY for 'pushing' cool air, and not 'pulling' hot air into the fan motor ... but, since it's intended use is for assisting furnace air to be moved, I can't see the heat bothering the motor (but, I'm a truckdriver, not a HVAC guy ) ... not knowing shit about HVAC, I would think you would want the 175cfm at the Inlet, and the 275cfm at the Outlet ... I'm thinking if that was reversed, the first fan would be fighting against some back-pressure, when it encounters the slower fan ... well, that's the theory for exhaust pipes, anyway
the image reaper Reviewed by the image reaper on . Calling SpaceNeedle. HVAC question. I was told to search you out because my question wasn't getting answered in my thread here: http://boards.cannabis.com/indoor-growing/125263-ventalation-fans-fans-fans-fans.html Ultimately my question boils down to this: (from the thread) I guess I just wanted to know where in an 18 foot run of duct that has a light in the middle of the run, would you place a 275 cfm and a 175 cfm fan to get the best cooling possible. Forget all that other stuff, if someone could just answer that it Rating: 5