Installed a 4 vent port (flanged), it came from a non-used furnace vent in my RV. Jury-rigged a temporary fan from an old microwave (120V AC fan). No idea of CFM. Temps dropped to 82.6 so far. Fan run independant of timer, always on. For now, anyway. Still planning DIY carbon filter--and more permanent fan--like in lots of y'all grow rooms, and described on the forums here. :) Loving 420Mag. FTW.