Belt Drive Whole House Fan includes a white, powder-coated shutter and a high/low/off wall switch, so there's nothing else to buy. Features a two-speed, PSC motor, four precision-balanced aluminum fan blades for greater air movement, steel venturi for enhanced durability and tough steel motor struts. The CX24BD-2SPD whole house fan has re-engineered bracing technology to virtually eliminate vibration. This Cool Attic house fans can be installed joist-in or joist-out. Capable of moving air up to 4,500 cubic feet per minute from up to 1,800 square feet on a single story. Requires eight to ten square feet NFA (net free area) of intake. Inadequate intake ventilation can lead to motor failure.