How Much Electricity Does a Bathroom Fan Use?

Bathroom fans help remove excess moisture and create a pleasant environment.

Building codes require a vent bath fan if there are no windows in the bathroom. Some homeowners also install ceiling fans instead of HVAC vents in the bathroom to reduce electricity consumption and in turn, save on electricity costs.

If you are thinking about installing bath fans, you may be wondering how much electricity does a bathroom fan use. The answer to this depends on the type and size of the fan.

Electricity Consumption of Bathroom Vent Fans

Bathroom vent fans remove humid air from the bathroom. The fans suck the moist air expelling it outside. The vacuum is filled with cool air that enters through the ventilation.

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The airflow rate of a vent fan is measured in cubic feet per minute (cfm). Standard vent fans require about 1 watt to move air at the rate of up to 5 cfm.

A bathroom measuring 1000 cubic feet (10ftx10ftx10ft) requires a fan that can move air at the rate of 1000 cfm. This fan will consume about 200 watts i.e. 1000/5 to remove moist air from the bathroom.

It is equivalent to about two 100 watts incandescent bulbs or twenty 10 watts LED bulbs.

For smaller bathrooms measuring 125 cubic feet (5ftx5ftx5ft), the appropriate fan should have an airflow rate of 125 cfm. The power requirement of a small bath vent fan will be 23 watts.

Also, you should note that some bath vent fans have additional features. Features like heat lamps, day and night light further increase the wattage of the fan.

  • A bath fan with a heat lamp will draw an additional 100 to 250 watts
  • For a fan with an integrated heater, the power consumption is about 1500 watts
  • The power consumption of vent fans with low wattage light range between 40 and 60 watts while night lights consume between 4 and 10 watts

Electricity Consumption of Bathroom Ceiling Fans

Ceiling fans are installed in bathrooms as a means to reduce the need for air conditioners, thereby resulting in reduced electricity consumption.

Instead of cooling the room by removing moist air like an exhaust fan, ceiling fans cool the room by blowing air across the room.

Most ceiling fans also come with a speed regulator. You get to control the speed of the fan by increasing or decreasing the voltage. The voltage is adjusted by the regulator by varying the current supplied to the motor.

Ceiling fans use more electricity at higher speeds and less electricity at lower speeds. To be more specific, a fan will use more electricity at a higher voltage setting and less electricity at a lower voltage setting.

The electricity usage of all appliances is known as power, which is measured in watts.

A typical bathroom ceiling fan will use between 40 watts and 100 watts depending on the voltage supplied to the fan.

If one kilowatt costs 10 cents per hour, the cost of operating a ceiling fan will be about 0.4 cents at lower settings and 1 cent per hour at higher settings.

Another important point to note is that larger fans use more power. Larger fans use more power to spin the blades that add to the electricity costs.

The power of a large ceiling fan will range between 50 to 130 watts. The electricity cost of using the fan range from 0.5 to 1.3 cents per hour.

Electricity Consumption of DC Ceiling Fans

DC ceiling fans are also used in certain bathrooms. These fans use direct current (DC) instead of alternative current (AC), the latter being used in most bathrooms.

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These fans are more cost-effective, using less than a third of the energy used by the older fans that use AC power.

Similar to AC fans, the DC bath ceiling fans consume more power at a higher speed and less power at a lower speed. Moreover, the size of the motor and fan blades also determines the electricity usage.

Bathroom DC fans use between 15 watts to 100 watts. They use about three times less power as compared to a similar power and size AC bath fan.

The cost of operating a DC fan is also much lower. You will save a lot of money by installing a DC fan in your bathroom.

Electricity Consumption of Box Fans

Box fans are preferable by some people instead of a ceiling fan as they make more white noise. However, a typical box fan tends to use about twice as much power as a ceiling fan.

For instance, if the ceiling fan consumes 40 watts, you can expect a box bath fan to use about twice as much power i.e. 80 watts. The cost of a box fan is also much higher.

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You can expect to pay between 1 cent and 2.6 cents per hour for operating the fan.

Despite the higher power consumption, some people prefer box fans as they produce white noise. The box fan will negate some of the outside noise resulting in a pleasant and relaxing environment.

The white noise that the fans produce is effective in blocking out outdoor noise.

Similar to the ceiling and vent bath fans, the exact power consumption of the box bath fans depends on the power of the motor and the speed setting. You should check the label on the appliance to know about the correct wattage.

The cost of operating the box bath depends on how much you use the fan during the day. Moreover, the energy tariff in your area will determine the cost of operating the box fan.

If you use the fan for six hours per day, the electricity cost of using the fan will be between 2.5 cents and 7 cents.

How to Reduce the Electricity Consumption of the Bath Fan?

Bath fans tend to add between $10 and $50 to annual electricity bills. You can take several measures to reduce the electricity consumed by the bath fans.

Here are a few tips that will help you to reduce the power used by the fans.

Don’t Leave the Bath Fan On All Day

Leaving your bath fan on all day is not a good idea. There is no sense in leaving the fan on all the time. This will result in increased electricity consumption and also accelerated wear and tear.

The appliance lifetime will reduce significantly if you keep the fan running all the time.

You should leave the bath exhaust fan on for only 25 minutes after having a shower. If you have a ceiling or box fan in the bathroom, you should turn on the fan when in the loo and turn it off when leaving.

Consider Automatic Fan Regulator

Consider installing an automatic bath fan regulator to save electricity bills. You can set a timer for the bath fan to run for a particular period.

In this way, you don’t have to remember turning the fan on or off.

Keep the Bathroom Door Slightly Open

Bathrooms can get hot and humid during the summers. You should consider letting the door open a few inches so that hot moist air doesn’t accumulate inside the bathroom.

This will reduce the need to run the bath fan for longer periods.

Buy the Right Size Bath Fan

Buying the right size bath fan is important if you want to save on electricity bills. You buy a fan with a cubic feet per minute (CFM) capacity that is appropriate for the bathroom size.

A small bathroom that is 80 square feet will require a bath exhaust fan with a capacity of 80 cfm. You will waste money both in terms of fan price and electricity cost if you buy an exhaust fan with greater capacity.

Install the Fan at the Right Location

You should install the fan at the right location as well to ensure proper operation. The bath fan should be near the shower or tub.

Avoid installing the fan right next to the HVAC vent. This is important as the forced air from the heating and cooling device will prevent proper ventilation.

Lastly, the bath fan should vent the air outside. The fan should not vent in the attic or other area inside the house. Proper location of the fan is important to ensure effective ventilation.

If you don’t place the bath fan in the correct location, it will use more power to remove moist and humid air inside the bathroom.

Frequently Asked Questions

How much does it cost to run a bathroom fan 24/7?

Running a bathroom fan 24/7 will vary in cost depending on the wattage of the fan and the cost of electricity in your area. For instance, a fan using 40 watts will consume 0.04 kilowatt-hours (kWh) per hour. If your electricity rate is $0.10 per kWh, running the fan continuously for 24 hours would cost approximately $0.96

How many amps does a bathroom exhaust fan use?

The number of amps used by a bathroom exhaust fan depends on the wattage of the fan. To calculate the amps for a given fan, divide its wattage by the voltage (usually 120 volts). For example, a 50-watt fan would use roughly 0.42amps (50 watts / 120 volts).

How much electricity does a kitchen extractor fan use?

Kitchen extractor fans have varying electricity usage depending on their size and power. They generally have a higher electric consumption than bathroom fans due to their higher airflow capacity. You can expect a typical kitchen extractor fan to use between 60 and 200 watts.

What is the power consumption calculation for exhaust fans?

To calculate the power consumption of an exhaust fan, simply multiply its wattage by the number of hours it’s in use. Example: A 40-watt bathroom fan used for 3 hours would consume 120 watt-hours (40 watts * 3 hours).

What is the cost of leaving the bathroom fan on all day?

The cost of leaving a bathroom fan on for 24 hours depends on both the wattage of the fan and the cost of electricity in your area. Using the example of a 40-watt fan and an electricity rate of $0.10 per kWh, the cost would be approximately $0.96 per day

What is the wattage of a 12-inch exhaust fan?

The wattage of a 12-inch exhaust fan varies by brand and model. It can range from as low as 60 watts to over 200 watts, depending on the efficiency and power of the fan. Always check the product specifications to confirm the wattage of a specific model.


Bathrooms can have an exhaust fan, ceiling fan, table fan, or standing fan. Each of these fans uses a varying amount of electricity.

You should understand the electricity usage of your bath fans as it will help you know better understand what contributes to your electricity bills.

Electricity usage of bathroom fans is measured in watts. Every bathroom fan has a watt rating that refers to the amount of power required to operate the electrical appliance.

Generally, fans with larger blades and higher speeds use more electricity. The type of fan and the accessories like night lights and heat lamps also increase the electricity usage.

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