My ceiling fan has a switch that reverses the direction the blades rotate. How do I know which direction to run the fan during warm- and cold-weather months?
During warm weather, you should run the fan so that the breeze blows downward. This wind-chill effect—the same cool breeze you feel when you roll down the window in a moving car—will cool you.
Many ceiling-fan manufacturers and various Web sites out there suggest that you run the ceiling fan so that it blows in the opposite direction—upward—when the weather is cold and the heat is on in your home. The idea is that the fan mixes the warm air collecting at the ceiling and moves it back down to the perimeter of room, creating a higher average room temperature and less need for heat. (All of the ceiling fans we recently tested have a switch that you flip to reverse the motion of the blade.)
But in our past tests, we found that the draft caused by the fan can have a chilling effect on people in a room—and lead to higher thermostat settings and more energy use. So we recommend that you not bother to reverse the motion of your fan—just leave it off during heating season. Note that there might be some situations where reverse operation would be be beneficial, such as in a room with a wood stove running or a very high vaulted ceiling.
If you’re looking to lower your energy bills during cooling season, use ceiling fans and turn off your air conditioning or turn up the temperature on your A/C a few degrees and let the fan go to work. Remember that ceiling fans cool you and not the space you’re in, so turn them off when you leave the room for an extended time so as to not waste electricity.
When shopping for a ceiling fan, you’ll find old-style models that conjure memories of Bogart and Bergman in Casablanca and versions that are modern twists on an invention that first appeared in the U.S. in the 1860s. In our latest report on ceiling fans, we found that while the pricier fans did have fancier finishes, they didn’t necessarily provide better performance. What’s more, most fans performed similarly in our air-movement tests.