Extremely Quiet: At less than .3 sones, this fan operates as quiet as a whisper Long Life, Guaranteed: Panasonic ventilation fans use less energy to move larger volumes of air; Less energy leads to less overheating and motor failure, saving you on repair costs; Included 6-year warranty on motor and 3-year warranty on parts Easy-To-Install: Designed for use with 4" oval ducts; Unique L-Shaped bracket simplifies installation and provides strong support Clean Air: Panasonic ventilation fans will increase your air quality, eliminating humidity, mold, mildew, and other air pollutants from any room Code Compliant: This product is ENERGY STAR certified and complies with ASHRAE 62.2, LEED, California Title 24, Washington VIAQ codes and standards