The Panasonic WhisperCeiling FV-05VQ5 Ceiling Mount Bathroom Fan - ENERGY STAR features super-quiet operation and high CFM-to-Watt efficiency. It has a totally enclosed condenser motor and a bladed blower wheel that quietly moves the air. It has a built-in damper to prevent back draft, which prevent outside air from coming through the fan. This fan is ENERGY STAR qualified as it protects the environment by saving energy.