You Should Turn on Your Ceiling Fan Every Time You Use Your AC

In winter, your local weather forecast may include the wind chill, which tells you how cold it’ll feel outside after factoring in how windy the day will be. Wind chill — which essentially comes from air movement — makes you feel a number of degrees colder than it really is.

A ceiling fan works on the same principle, creating a breeze that provides a cooling effect even though it doesn’t reduce the temperature of the space it’s in. In fact, a fan’s motor technically produces a minute amount of heat, but for any people (or pets) within its radius, that tiny difference is negated by the cooling sensation it provides.

“Human beings evolved to cool via air motion,” Danny Parker, the principal research scientist at the Florida Solar Energy Center, explained in a phone interview. “Even a slight amount of air motion feels better to us in almost any overheated environment.”

That air motion has a two-pronged effect. One, it hastens the evaporation of moisture from your skin’s surface. Two, it creates convection around you, which removes heat. “The human body creates heat at the rate of about 300 to 400 watts when resting,” Parker explained. “Convection breaks that up, so you’re not encased in heated air.”

Of course, sometimes it’s so hot that there’s not much difference between the ambient temperature and the temperature of the air immediately around you. That’s where AC can help. But if you’ve ever spent a summer in an office that relentlessly blasts the AC, you probably already know how unpleasantly chilly it can feel to rely on AC and nothing else.

“If you’re hot, circulating air from a fan close by will make you feel more comfortable more quickly than you will just by being submerged in 74-degree or 72-degree air,” Parker said.

Although any type of fan can create evaporative cooling, a ceiling fan usually has a wider diameter than a standing fan or a window fan, which allows it to move more air and potentially cool people within a greater area.

A ceiling fan’s location also makes it ideal for circulating air throughout a room, which can prove handy in certain situations. For example, take mini splits, which tend to be installed higher up on a wall than window AC units. “In a bedroom with a split unit, one side of the bed may get that downdraft from the unit, so the person on that side of the bed may feel freezing while the other person is hot,” Schiavon explained. “With a fan, you can mix the air to create a much better, more homogenous temperature in the space.”

Fans can also provide necessary improvements in air circulation if you have central AC that relies on floor vents, adds Wirecutter writer Liam McCabe, who covers large appliances and HVAC systems. “The cool air just sort of sits near the ground, especially if you have a subpar AC system that doesn’t actually distribute the cooling evenly,” Liam says. “So it’s not just the evaporative effect where a fan can help; it can also pick up the slack when you want that conditioned air to circulate.”

One potential concern regarding fans — at least for people in super-sticky climates — is that they’re not as good as air conditioning at dehumidifying a space.

That’s because, even though air circulation increases evaporation, it doesn’t actually remove moisture from the air. But when an air conditioner cools the air below its dew point, that moisture condenses onto the AC system’s evaporator coils and then drains away. “If you lower your AC, it’s not going to do as much dehumidification,” Liam explains. “So that’s something to consider, depending on the humidity.”

Another issue is that, unlike people, ceiling fans are anchored to a fixed location, which limits their effectiveness. “For people who are not directly underneath a fan, the effectiveness is dramatically reduced,” Parker said.

And if you’re spending eight hours in a bed below a ceiling fan, you might experience some minor discomforts from the sustained exposure. “There is a part of the population that may get dry eyes or a dry nose,” Schiavon said. “Or if there’s pollen or pollution in the air, a fan can basically increase the amount of pollen or pollution that can hit the eyes, nose, and mouth. In some environments, that may not be ideal.”

If you’re waking up and experiencing dryness in your eyes, throat, or nasal passages, you can try reducing your fan’s speed to “the lowest speed that will still give you the cooling that you want,” Parker said.

Lots of factors determine the size of your energy bill in the summer, including whether you use window ACs, central AC, or mini splits, as well as how many window AC or split units you have, how well your home is insulated, the average electricity rate where you live, and of course, how hot it gets.

A ceiling fan has its own variables, such as the size of its blades (the longer the blade, the more energy the fan uses) and how efficient its motor is. Even with so many variables, however, running a ceiling fan and raising your AC’s temperature setting by a few degrees will use less energy in virtually any situation.

Here’s just one example: Our favorite budget window AC, the Frigidaire FHWW084TE1, uses 714 watts of power, according to its online specifications. Meanwhile, the Westinghouse Comet 52-Inch Indoor Ceiling Fan, a fan that we recommend, uses only 16 watts of power.

Even if you have an ancient, inefficient ceiling fan, the energy savings can still be meaningful. According to Schiavon, “an old fan uses maybe 100 watts” of power, which is much more efficient than a modern AC unit.

As for how much money you can save, the New York State Energy Research and Development Authority states, “Each degree above 75°F that you set your air conditioner’s thermostat saves you 3 percent of the energy used to cool your home.” So if you set your AC to 79 degrees — 4 degrees higher than the recommended 75 degrees — because you’re also running your ceiling fan, that would shave about 12% off your bill, with only pennies per day added back onto your bill by the fan.

That’s similar to the findings from a study of residences in Florida (co-authored by Parker), which found that “using ceiling fans combined with raising a home’s temperature 2° F will generate about a 14% net savings in annual cooling energy use (subtracting out the ceiling fan energy and accounting for internally released heat).”

However, Liam explains that the cost savings might not be as much, depending on where your fans and your ACs are located: “If the fan isn’t in the same room as the thermostat, it might not help in terms of energy savings,” he says.

Perhaps the best thing about a fan is that practically any model can provide a significantly more pleasant environment amid sweltering heat, even if it’s not the most efficient fan. As Parker said, “it’s all about the air motion where you are.”

This article was edited by Megan Beauchamp and Maxine Builder.