Broan Flex Series 50 Cfm 0.5 Sones Ventilation Fan Energy Star Broan Ae50 Flex Series 50 Cfm Ceiling Exhaust Bath Fan, Energy Star Offers Easy, Room Side Installation, With “No Attic Access Required”. Ceiling Mounted Ventilation Fan Features Foldable Mounting Ears And Ezduct Connector For Easy Installation. New Duct Damper Technology Provides A Tighter Seal, Resulting In Reduced Warm And Cold Air Backdrafts. This Energy Efficient Fan Operates At 50 Cfm And A Very Quiet 0.5 Sones.