Friday, September 28, 2007

Selecting Your Attic Fan


A two-speed fan permits the entire house to be ventilated quickly on high speed (such as when the occupants first arrive at home) and then provides gentle air circulation at the lower, quieter speed. A variable speed unit offers more flexibility in selecting the desired air movement.


Control may be a simple on/off pull or wall switch, a multi-speed rotary wall switch, or a timer that automatically shuts off the fan at pre-selected time intervals.


Dampers or louvers typically operate automatically whenever the fan is on. Motorized dampers are available but are not necessary if the louvers are correctly installed and maintained.


A direct drive unit has its fan blades attached directly to the motor shaft. This type of unit is usually less expensive to buy and operates at a higher speed than its belt-driven counterpart. A belt-driven unit typically features a motor driving a slower-moving,larger-diameter fan with four or more blades. It may be quieter, but will require maintenance of the pulley and belt.

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