Cool Attic CX242DDWT Drive Drive 2-Speed Whole House Fan with Shutter, Exhaust Fan, 24-Inch NA Made in USA WHOLE HOUSE FAN: The cool attic 24 in. belt drive 2-speed whole house fan is designed for houses with 1,800 sq. ft. attics. It offers an efficient way to reduce cooling costs, while keeping your whole house more comfortable. It features a powder coated finish for weather resistance. ATTIC FAN: It works by pulling fresh air in from the outside and expelling the warm air up into the attic and pushing it out through your attic exhaust vents. This unit requires a minimum of 8 - 10 sq. ft. of net free exhaust vent area to perform quietly and efficiently. DIRECT DRIVE FAN: Dual, self-aligning ball bearing mechanisms, and precision-balanced 4-blade aluminum fan assembly, contribute to quiet, reliable performance and longevity. This unit requires a minimum of 8-10 sq. ft. of net free exhaust vent area to perform quietly and efficiently. 30-inch white, powder coated finish automatic shutter has 95% plus air closure FAN WITH SHUTTER: It has Joist-in/joist out installation with steel venturi for enhanced durability. It ensures CFM high and low ratings at 4600 and 3200 to effectively ventilate single story single family sized homes. Re-engineered bracing system creates a more stable motor mount, is stronger than tube-style bracing, and virtually eliminates vibration. It provides proper ventilation of attic space. EXHAUST FAN: It has precision-balanced aluminum fan blade assembly with 4 blades with CFM of 4,600/3,200, 2-speed, thermally protected PSC motor for 2,000 - 3,000 square feet on one story and Left Bowl Length is 14.9. High/low/off wall switch is included.