In theory, a ceiling fan saves energy because the breeze evaporates moisture on your hot, sticky skin, cooling you down without the benefit of air-conditioning. In practice, though, it doesn't always work that way. People keep fans running with the AC going full blast, or leave them on when no one is in the room, which wastes their cooling power. Here's what to do instead. First, make sure any fan you buy is Energy Star rated. Lighted ones use fluorescent bulbs instead of hot-burning incandescents or halogens and are up to 50 percent more efficient than standard models.
Second, once the fan is installed, raise your air conditioner setting by 5 degrees. (Experiment with your heater setting, too. You may be able to lower it a degree or two if you run the fan backward so it pushes rising warm air down.) And finally, install an occupancy sensor switch that shuts the fan off if no one's in the room.
You can see our full step-by-step installation instructions in How To Install a Ceiling Fan
.52-inch Calera Ceiling Fan:
$100Retrofit electrical box:
$20Motion-sensing wall switch: