Broan Humidity Sensing Bathroom Exhaust Fan Energy Star, 50-110 Cfm Broan Ae50110Dcs Flex Dc Series Humidity Sensing Exhaust Bath Fan, Energy Star Offers Easy, Room Side Installation, With “No Attic Access Required”. Ceiling Mounted Ventilation Fan Features Foldable Mounting Ears And Ez Duct Connector For Easy Installation. New Duct Damper Technology Provides A Tighter Seal, Resulting In Reduced Warm And Cold Air Backdrafts. The Humidity Sensing Feature Will Automatically Turn The Fan On When A Preset Level Has Been Reached, Thus Allowing For Proper Ventilation Throughout The Room. This Energy Efficient Fan Operates At A Selectable Cfm Range Of 50-80-110 At A Quiet Operation Of <0.3-0.4-0.9 Sones.