Using an exhaust fan to rid a bathroom of humidity can be a tricky balance.
Turn it off too soon, and you may leave behind damaging moisture. Leave it on too long, and you waste energy by sending heated or cooled air outside unnecessarily.
A new fan switch takes away the guesswork.
The DewStop switch senses condensation in the room and turns the exhaust fan on and off automatically. The wall-mounted switch, which works with an existing fan, can be operated manually.
The DewStop sells for $59 at www.dewstop.com. A switch that controls both a fan and its built-in light is $69.