Hi, SO I was running some new wire through a wall and when I removed the face plate for the bathroom exhaust fan I found out there was no ducting. The way this was installed it uses the 2x4 cavity as the "ducting" and then at the bottom (yes it runs down not up and out the roof) there's dryer vent that connects it to a high CFM exhaust fan. There's alot of dust and stuff in there but there's no mold... This fan also works as a de-humidifier for the whole house until recently when I installed a 2nd exhaust fan downstairs in that bathroom and am using that as a dehumidifier as well. Is this something I should be concerned with? Is there anything I should look for besides rot/mold? It's one of those BIG high CFM fans or whatever that are big and round and would normally be in the attic... I figure I could probably just run new dryer ducting (or the solid stuff) down to the floor and install the metal angle ducting behind the existing grill... but is that a good idea or even necessary? Any thoughts?