How many watts does a fan use?
A typical household fan uses 15 to 100 watts on its normal or high speed, which is well under one amp on a 120-volt outlet. The motor is the only thing drawing power, and a fan motor is small: it spins a blade against air, not against a compressor or a heating element, so it never lands anywhere near the 1,500-watt range of a space heater or the surge of a refrigerator. Lower speeds use less, because a slower motor draws less current, so the same fan might pull 75 watts on high and 25 on low.
By type, the rough numbers are: a 20-inch box fan about 50 to 100 watts, a pedestal or stand fan about 30 to 100 watts, a tower fan about 30 to 60 watts, a table or desk fan about 25 to 50 watts, and a small clip-on or USB fan just 2 to 10 watts. A ceiling fan spans the widest range, from about 15 watts on low to 90 watts on high for a large 52-inch model. The exception at the top end is a whole-house or attic fan, a much larger unit that pulls 120 to 700 watts because it is moving the air in an entire house, not one room.
Fans run on 120 volts and never need a 240-volt circuit. A plug-in fan has only a small startup bump as the motor spins up, nothing like a compressor's surge, so the running watts on the label are close to the real draw. That makes a fan one of the easiest loads in the house to put a number on and to run off a small battery or inverter.
How many watts does a box fan use vs a ceiling fan?
A box fan uses about 50 to 100 watts on high, with most common 20-inch models near 75 watts, while a ceiling fan uses about 15 to 90 watts depending on its size and speed. A box fan looks like it should use less because it is small and portable, but it packs a fast motor into a small blade, so on high it often draws as much as or more than a large ceiling fan turning slowly. A ceiling fan moves a lot of air with a big, slow blade, which is a more efficient way to shift air, so on low speed it can sip just 15 to 30 watts.
The single biggest swing in fan wattage is the motor type. A DC-motor fan uses roughly 70 percent less power than an AC-motor fan for the same airflow. A standard AC ceiling fan might pull 75 watts on high; a DC-motor model moving the same air draws closer to 30 watts, and a DC pedestal or tower fan can run on 5 to 20 watts. DC fans cost more up front and usually come with a remote, but if a fan runs for long hours, or if you are running it off a battery, the lower draw pays off. Look for the wattage on the box or an Energy Star rating rather than guessing from the size.
One more detail on ceiling fans: the light kit often uses more power than the motor. A fan motor on medium might draw 30 watts while a bank of old incandescent bulbs in the same fixture burns 180 watts or more. Swapping those for LEDs drops the light draw to 20 or 30 watts and makes the whole fixture cheaper to run than the fan alone used to be.
How much electricity does a fan use per day, and what does it cost?
A fan costs almost nothing to run. A 75-watt box fan running 24 hours straight uses 1.8 kWh, about 31 cents a day at the US average rate near 17 cents per kWh, or roughly $9 a month if it truly never turned off. Run that same fan overnight for 8 hours and it uses 0.6 kWh, about 10 cents. A ceiling fan on low at 25 watts running all night uses about 0.2 kWh, around 3 to 4 cents. These are the smallest numbers you will find for any appliance that makes a real difference to comfort.
The math is simple because a fan does not cycle like a fridge or a dehumidifier; it just runs at a steady wattage the whole time it is on. Multiply the watts by the hours and divide by 1,000 to get kWh, then multiply by your electricity rate. A 100-watt fan on high for 24 hours uses 2.4 kWh, around 41 cents a day; a 30-watt DC ceiling fan for the same 24 hours uses 0.72 kWh, about 12 cents. For the full walk-through of turning watts and hours into a monthly dollar figure, see watts to kWh, and for the difference between power and energy, kW vs kWh.
Even run hard, a few fans add only a few dollars a month to a bill. Three fans running most of the day might total 10 to 15 kWh a week, a couple of dollars. That is why a fan is almost always the right first move for comfort: the cost of running it is lost in the rounding next to the air conditioner it can help you turn down.
Does a fan cool the room, or just you?
A fan cools you, not the room. It does not lower the air temperature at all; if anything, the motor adds a trace of heat. What a fan does is blow air across your skin, which speeds up the evaporation of sweat and carries body heat away, so you feel about 4 to 8 degrees cooler even though a thermometer on the wall does not move. This is the one fact that explains everything else about using a fan well.
The practical rule that follows is turn the fan off when you leave the room. A fan cooling an empty room is pure wasted electricity, because there is no skin for the moving air to cool and the room temperature is unchanged either way. This is the opposite of a fridge or a dehumidifier, which have to keep working whether you are there or not. A fan only helps while someone is in the airflow, so a fan on a timer or one you switch off on the way out is a fan you are using correctly.
It also explains why a ceiling fan should spin counterclockwise in summer (pushing air straight down over the people below for that wind-chill effect) and why running one in an unoccupied room to 'circulate air' saves nothing on cooling. If you want to actually lower the room's temperature, you need an air conditioner or to pull in cooler outside air, which is where a fan's low wattage becomes a strategy rather than just a comfort.
Is a fan cheaper to run than air conditioning?
A fan is dramatically cheaper than air conditioning, using about 1 to 5 percent of the power. A 75-watt fan draws a tiny fraction of a window AC's 500 to 1,500 watts or a central system's 3,000 watts or more. Running a fan costs cents a day; running central AC can cost a few dollars an hour. They are not in the same league, which is exactly why the two work best together rather than as either-or.
The money move is the thermostat trick: because a fan makes you feel 4 or more degrees cooler, you can raise the AC setpoint by about 4 degrees and feel the same comfort while the compressor runs much less. Set the thermostat up, run a fan in whatever room you are in, and you get the fan's near-free comfort plus a real cut in the AC's big electric load. Turn the fan off when you leave that room, and the AC setpoint does the rest for the empty house.
If a fan alone is not enough on a hot evening but you would rather not run the AC, a whole-house fan is the middle option. It uses 120 to 700 watts, far less than AC, and pulls cool evening air in through open windows while exhausting hot air out the attic, dropping the whole house's temperature in a way a box fan cannot. It is a hardwired install in the ceiling, so it is a job for an electrician, but it runs for pennies compared to cooling. If you are weighing solar for the cooling you cannot skip, see whether solar can power an air conditioner and how the fan load compares to running a whole house.
Can you run a fan on solar or a battery?
Yes, easily. A fan is the one comfort appliance that solar and batteries run without a fight, which is the opposite of nearly every other household load. A 12-volt, 100Ah battery holds about 1 kWh usable, enough to run a 50-watt fan for roughly 20 hours, or a 25-watt DC fan for a day and a half. A single 100-watt solar panel makes more energy on a sunny day than a fan uses, so a small panel-and-battery setup keeps a fan running through the night and recharges the next day. See the specifics in what a 100Ah battery can run.
Because the draw is so small and there is no compressor surge, you do not need a big inverter. A modest 150 to 300-watt inverter runs most fans, and a small plug-in portable power station or solar generator runs a box fan all night and still has charge to spare in the morning. A DC-motor fan makes this even easier, and some 12-volt fans run straight off a battery with no inverter at all, which is why fans are standard kit for RVs, vans, and off-grid cabins.
This is the payoff worth remembering after a long list of appliances that punish solar: a fan is tiny, steady, and surge-free, so it is the first load to put on a battery and the last to worry about. To see how a fan fits alongside everything else you might run off panels and storage, size a system with the solar panel calculator.
Frequently asked questions
How many watts is a normal fan?
A normal household fan uses 15 to 100 watts. A common 20-inch box fan is about 50 to 100 watts on high (most near 75), a tower or pedestal fan about 30 to 100 watts, a ceiling fan about 15 to 90 watts depending on size and speed, and a small desk or USB fan just 2 to 50 watts. Lower speeds use less, and a DC-motor fan uses roughly 70 percent less than an AC-motor fan for the same airflow.
How much does it cost to run a fan all night?
Almost nothing. A 75-watt fan running 8 hours overnight uses about 0.6 kWh, which is roughly 10 cents at the US average rate near 17 cents per kWh. A ceiling fan on low at 25 watts uses about 0.2 kWh overnight, around 3 to 4 cents. Even a large 100-watt fan all night costs about 14 cents. Running a fan while you sleep is one of the cheapest things you can plug in.
How much does it cost to run a ceiling fan on high for 24 hours?
A ceiling fan on high uses about 60 to 90 watts, so running it 24 hours straight uses roughly 1.4 to 2.2 kWh, which costs about 25 to 37 cents at 17 cents per kWh. An efficient DC-motor ceiling fan drawing 30 watts on high uses only 0.72 kWh in a day, about 12 cents. Remember the fan only helps the people in the room, so running it 24 hours in an empty room spends that money for no benefit.
How many ceiling fans can you run on a 20 amp breaker?
A 20-amp, 120-volt circuit supplies up to 2,400 watts, or about 1,920 watts for a continuous load. At roughly 75 watts each, that is around 25 fans by the motor alone, so a fan's draw is rarely the limit. The real constraint is usually the light kits and everything else sharing the circuit, not the fans. Code treats most ceiling fan and light circuits as general lighting, so in practice you wire several fans per circuit and the breaker is never the problem.
Can you run a fan on solar panels or a battery?
Yes, and a fan is one of the easiest loads to run off solar. A 12-volt, 100Ah battery (about 1 kWh usable) runs a 50-watt fan for roughly 20 hours, and a single 100-watt solar panel makes more energy on a sunny day than a fan uses. There is no compressor surge, so a small 150 to 300-watt inverter or a basic portable power station handles it, and many 12-volt DC fans run straight off a battery with no inverter at all.