If you have a super efficient DC motor ceiling fan like the Emerson Midway Eco (shown to the left), It costs less than 2 tenths of one cent per hour ($0.0018) to operate, which comes out to about 4 cents per day, $1.20 per month or $15.58/year. Typical fans with AC motors cost 5 to 8 times as much to operate, so upgrading to Ceiling Fans with DC Motors can have a significant impact on reducing your electric bill, particularly if you have several fans in your home.
Calculating the cost to operate a ceiling fan is a simply a matter of knowing how many watts the fan uses and multiplying that by the cost per kWh of electricity you are being charged by your utility company. This will give you the cost per hour to run the fan. Our calculations are based on the national average of electricity at $0.1186/kWh with the fan running at high speed. On low speed, the Midway Eco costs even less. The range of wattage between various brands and models of ceiling fans (without lights) is anywhere from 15 watts to 120 watts per hour. Based on that, here is how much it would cost to operate the most and least energy consuming ceiling fans on the market if either fan was left running 24 hours a day for an entire year. No one is likely ever to use their ceiling fan even remotely close to that many hours, but we are taking these calculations to an extreme to show how cheap it can be to operate a fan.
So, the most it can cost you to run a ceiling fan without lights is about $126 per year, which is equal to about $10 per month and the least it will cost you is about $15 per year, which comes out to just $1 per month...which is amazingly cheap.
The above calculations did not consider having a light fixture on the ceiling fan. The wattage of the light fixture can have a much greater impact on the cost than the motor. When calculating the cost to operate a fan with the lights on, you must add the wattage of the lights to that of the motor. The range of wattage for a ceiling fan light fixture is anywhere from 13 watts to 190 watts. FYI: Ceiling fans used to have up to 300 watts with a 5-light fixture using 60 watt bulbs, but the EPA began enforcing regulations that now limit the maximum wattage of the light to 190 watts. Here are the calculations if you leave you fan running with the lights on 24 hours a day for a full year:
So the conclusion I am hoping that you will make here is that the light fixture you choose for your ceiling fan is what will cost you the most in the long run. Keep in mind that these estimates above are for operating each ceiling fan 24 hours a day for 365 days...so you can cut those numbers by about 75% or more to come to a more realistic usage.
Operational Cost Calculator(Instructions/Details)