The Premium WhisperGreen-Lite™ series incorporates an enclosed DC, 2 speed motor designed for extremely quiet, energy-efficient operation. The permanently lubricated motor is engineered for trouble-free, continuous run for up to 5 years.
The Premium Light Series use one 32 watt CFL lamp for bathroom lighting, and are designed to provide both bathroom exhaust and whole house ventilation. The low speed constant is adjustable and the high speed is fixed. This allows you to establish a low speed to accommodate your whole house ventilation needs and still have the high speed boost for bathroom needs. There is a high speed extended run delay adjustment, that lets you run the high speed boost for and extended time after you switch it to low speed constant, to allow for better exhaust of moisture and pollutants after a shower. These fans feature built-in intelligence called SmartFlow™ Optimum CFM Technology. This unique "electronic-brain" lets the fan perform at a constant CFM regardless of elbows and other factors up to a .25 static pressure, which might hinder performance. Basically, when a WhisperGreen fan faces static pressure, its speed is automatically increased to ensure that the desired CFM is actually achieved. This allows the fan to perform as rated and makes for easier sizing.