Broan AE110S Flex Series 110 CFM humidity sensing exhaust bath fan, 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. With the humidity sensing feature, the bath fan will automatically turn on and off when humidity in the room reaches the set point by the consumer. This energy efficient fan operates at 110 CFM and a quiet 1.0 sone.