Quiet Fan Control -- If the application is one ceiling paddle fan, a quiet (step) fan control is the best choice. Quiet fan-speed controls will not cause fan-motor hum, making them ideal for bedrooms, children's rooms, media rooms, and other locations where noise is particularly important.
Fully Variable Fan Control -- Although fully variable (full range) fan-speed controls are an option for controlling one single ceiling paddle fan, they are the only choice for controlling more than one ceiling paddle fan, bathroom, whole-house/attic, range hood, agricultural fans and heat exchangers.