A bath fan can save energy or waste it, depending on how long you let it run after a steamy shower. If you don't let it run long enough, a lot of humidity is left in the air, and that forces your air conditioning system to work much harder. If you leave it on too long, the fan is needlessly pumping heated or cooled air outside while drawing in outside air—that, too, makes your HVAC system work harder.   


Installing a humidistat or timer switch
Removing an existing fan switch and installing a humidistat or timer switch is a simple job that takes less than an hour.

The best solution to both problems is to replace your fan switch with a humidistat switch. By sensing the humidity level, the switch will run the fan as long as needed but no longer. Humidistat switches start at about $50. If that's more than you're willing to spend, consider a timer switch, which costs about half as much. Either way, installing a dewstop fan switch is no more difficult than replacing a standard light switch.



— Gary Wentz, Senior Editor


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