Gramly Green Construction

How Ceiling Fans Save Energy

Fans used to supplement air conditioning save energy by permitting a higher thermostat setting. Air movement from the fan evaporates moisture on the skin and makes a person feel cooler. With this cooling effect, most people can raise their thermostat and feel just as comfortable. For every degree you raise the air conditioning thermostat above 78 degrees, you can save 3 percent to 5 percent on cooling costs. However, there are no energy savings if you use a ceiling fan and do not raise the air conditioning thermostat. In fact, since the fans themselves use energy, it will actually cost you more! If you want to save money by using fans, the key thing to remember is that fans cool people. They don't cool air. They don't cool rooms. So run the fans only when there are people in the room.

n theory, ceiling fans can also save energy in the winter. By reversing the direction of flow, the fans suck air up and push it around, theoretically pushing the warmer air at the top of the room down to where the people are. If it causes the air around the thermostat to stay warmer, then it will cause the heater to run less, which will save you money. There is no research that demonstrates this actually happens in the real world. If you do run the fans in winter, be sure to run them on the lowest speed. Remember that air flowing over your body will cool you off in the winter, it can just feel drafty, which can lead to cranking the thermostat up rather than down.

How Much Energy Do Ceiling Fans Use?

Fans use no more electricity than light bulbs. Typical wattages for various ceiling fan sizes are:

  • 36" = 55 watts
  • 48" = 75 watts
  • 52" = 90 watts
  • 56" = 100 watts

For example, a 48", 75-watt fan used 10 hours a day at half speed or less would cost $2.90 a month to operate.

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