Forgot to mention my room is supplied by 8 in solid round duct and vented by 10x12" square duct into a Broan 1200cfm motor. But at 10 percent running on the speed selector and using the 4in dryer vent right to my ashtray. I have to clean the room once a month. So unless I have company over I use the set up with the dryer vent. (I just made a cardboard adaptor that fits in the ceiling with the 20ft of 4" flex vent to the ashtray.....) company comes over and I run the system higher% cfm and put back in the 12X12" vent screen in the ceiling.
This is my fix for when I'm smoking alone. Blow right at the 4in flex....
