Whole House Fan Mounting Location Ceiling Quiet Design Yes Number of Speeds 2 Nameplate Voltage 120V AC Speed Controllable No Blade Diameter 18 in Drive Type Direct Drive Maximum Airflow 4 415 cfm Maximum Noise Level 1.8 sones Wattage 551 W Coverage Area 2 207 sq ft Rough Opening Type Square For High-Static Pressure Applications Yes High-Efficiency Motor No Number of Blades 3 Blade Material Steel Housing Material Steel Grille Material Aluminum Standards UL Listed