This thread is awesome for the first timers. It should be required reading before posting questions to the board! What a great community asset. I am a noob. In the design phase, studying and researching for a room that I will build in the next 6 - 8 weeks. This info is invaluable. I have a few observations.

1. You could employ a few iris valves into intake duct or even directly into the wall. Coupled with a fan controller this would allow micro adjustments for flow control need to defeat noise.

2. In the venting calculation it would be useful to have a multiplier that accounts for a reduction in the vent duct - say you have to drop from an 8" duct to a 6" duct.

A practical question - is there any reason to not leave the fans running all of the time? My major concern is odor control so I would prefer to just let the fan run. Also, can anyone comment on carbon filters? I am willing to invest what ever is needed for odor control. Will a good carbon filter completely eliminate odor? Completely? If so, any recommendations? Perhaps coupled with a ONA type neutralizer?