I have heard of a bath rm vent, which uses filters and doesn't exit to the exterior. I haven't seen the vent, but I wanted to know a little something about it and what better place than NACHI inspectors
I find it hard to believe that a vent not exhausted to the exterior would have much value eliminating excessive moisture from the room.
I have see what bath room vents do to an attic not good .
There is no way a filter is going to remove the moisyure .
I put this right up there with the save your heat and exhaust your dryer into the home .
Both add moisture where it usually a bad thing.
Something like this Danny? I have since seen two or three more of these, always in older aprartments being converted to condos.
I've seen a lot of them in the powder room of condos and, yes, maybe apartment conversions).They're probably useless, but typically tusk-colored plastic, about 4X10 inches, with a small, cloth filters. I descibe them as venting internally, etc, etc, and move on.