Product review (5 stars): Saves the fan and electricity
We were always forgetting to turn the bathroom fan off and occasionally not turning it on before taking a shower. Leaving the fan on wastes energy by turning the fan and also by exhausting conditioned (heated or air conditioned) are from the house. Not only that, very few residential bathroom fans are designed to run continuously so they get noisy and wear out prematurely if not turned off when their not needed.

The reason we purchased this device is because our master bedroom is very well insulated. Forgetting to turn on the fan may lead to condensation on the windows and above the sealing. Because the WhisperControl Condensation Sensor senses humidity and turns on, we can safely forget to turn the fan on since it detects high humidity and automatically turns on until the humidity level drops.