In summer, a fan saves only when you raise the thermostat about 4°F

In summer, raise the thermostat about 4°F whenever a ceiling fan runs counterclockwise, the amount DOE's Energy Saver guide (2022) says a fan allows "without any loss in comfort", and switch the fan off when you leave the room. The higher setting is the condition. ENERGY STAR's ceiling fan tips say ceiling fans cool people, not rooms. A fan that runs in an empty room only adds its own kWh. ENERGY STAR says to turn it off to save energy, and to adjust the thermostat when it runs. Both changes are free, and renters and owners can make them.

The saving comes from the higher setting, not the fan

DOE's 2022 guide explains the mechanism. Ceiling fans cool by creating a wind chill effect, which can allow you to turn up the thermostat a few degrees; the guide's own figure is about 4°F. Its cooling tips say to set the thermostat as high as is comfortable when you're home and awake, to raise it when you're sleeping or away, and to keep the comfort and safety of any pets in mind. The fan stretches that first setting. Nobody in the room? Fan off.

ENERGY STAR's tips make the same two points from the fan's side. If the room is unoccupied, turn off the ceiling fan to save energy. When it is on, remember to adjust the thermostat: ENERGY STAR says additional energy and dollar savings could be realized with that step.

The thermostat has a fan setting of its own, and it runs a different fan. DOE's guide says to leave that switch on "Auto" unless an indoor air quality professional has set up your system to operate continuously for health reasons.

A fan without a higher setting only adds kWh

Cooling tops the list. EIA's Electricity use in homes page puts air conditioning at 19% of residential site electricity in 2020, the largest single end use, and says about 89% of homes used it that year. The guide to where home energy goes sets that share beside heating and water heating.

Example, with published figures and one assumption. EIA's RECS 2020 Table CE5.3a puts average consumption at 226 kWh a year for ceiling fans in homes that used them, and 2,318 kWh for air conditioning in homes that used it. The US average residential price was 18.31 cents per kWh in July 2026, the latest month in EIA's Electric Power Monthly, Table 5.6.A (preliminary); pricing a whole year at that one month's rate is the example's assumption. Fans: 226 × 18.31 cents = $41.38. Air conditioning: 2,318 × 18.31 cents = $424.43. The fans use just under a tenth of the air conditioner's kWh (226 ÷ 2,318 = 9.7%). With the thermostat unchanged, the $41.38 lands on top of the $424.43. With the thermostat raised while the fans run, they pay their way only when the air conditioner sheds more kWh than they use. It is the same kWh-times-rate arithmetic used to price any appliance.

Hot, humid places run both harder. The same EIA table puts households in its hot-humid climate region at 366 kWh a year for ceiling fans and 4,173 kWh for air conditioning in 2020.

Counterclockwise in summer, clockwise on low in winter

DOE's 2022 guide gives both directions: counterclockwise in summer to create the wind chill effect, and clockwise in winter to force warm air down from the ceiling. ENERGY STAR's tips add a check and a speed. Stand directly under the fan in summer and you should feel a cool breeze. In winter, run it at low speed in the clockwise direction; the gentle updraft forces warm air near the ceiling down into the occupied space. Check the fan's manual for how to reverse the motor. The switch costs nothing.

The heating thermostat follows its own winter rule; with a furnace, that is the winter setback.

Adding or replacing a fan is a bigger job. If you buy one, ENERGY STAR's ceiling fan page says certified fans are up to 44% more efficient than conventional fans, under a specification effective June 15, 2018. Renters ask the landlord. Owners hire a licensed electrician and ask about two points from ENERGY STAR's installation tips: a UL-listed metal box marked "For Use With Ceiling Fans", which ENERGY STAR says you will most likely need when replacing a ceiling fixture, and anchoring the fan to a ceiling joist where possible, since fans can weigh as much as 50 pounds.