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How Many Watts Does a Box Fan Use? (Power Consumption)

Written by Edwin Jones / Fact checked by Andrew Wright

How Many Watts Does a Box Fan Use

A box fan is a type of portable electric fan that provides a cooling system and creates airflow in indoor spaces including homes, workshops, and offices. It requires power which is typically electricity to function. With this, how many watts does a box fan use?

The electrical consumption of a box fan varies depending on different factors including, but not limited to, speed setting, size, and design. On average, a box fan consumes between 20 to 120 watts of power per hour.

Factors Affecting Box Fan Power Usage

There are different factors that can affect the box fan power consumption. Some of the main factors are:

1. Fan Size


Like any other portable electric fans such as ceiling fan and floor fan, the size of the motor and blades of a box fan can influence its power consumption. A large box fan with bigger blades and motors consumes more power to operate in comparison to a small fan.

The standard box fan size is the 20-inch box fan. It typically consumes 70 to 120 Watts. See the chart below for a comparison of box fan wattage based on size.

Size Power Consumption per hour
USB box fan 5 watts
8-inch Box Fan 20 to 40 Watts
10-inch Box Fan 30 to 50 Watts
12-inch Box Fan 40 to 60 Watts
14-inch Box Fan 50 to 70 Watts
16-inch Box Fan 60 to 100 Watts
20-inch Box Fan 70 to 120 Watts

2. Speed Setting


Usually, a box fan comes with different speed settings including low, medium, and high. With this, the higher the speed setting, the more energy usage it has. Below are the average power consumption based on speeds.

  Lowest speed Medium speed Full speed
Wattages 47.3 watts 59.5 watts 73 wats
Power consumption percentage 65% 82%  

3. Build Quality


The quality of materials and construction can significantly impact the power consumption of a box fan. For instance, box fans made with high-quality components offer better energy efficiency.

4. Blade Design


 The shape and design of the fan blades can also affect the power consumption of a box fan. Box fans with aerodynamic fan blades require less power to generate the same airflow that other fans can provide.

5. Motor Efficiency


The efficiency of the motor can affect the power consumption of a box fan. A more efficient motor can provide the same airflow while consuming less power.

6. Operating Conditions


Using a box fan in a hotter environment requires its motor to function harder, increasing power consumption.

Furthermore, the number of hours the box fan is running can affect the energy consumption within a period. For instance, the longer the operation time, the more power consumption.

For an accurate measurement of power consumption, it is always significant to check on the specific wattage rating, including in the label or the user manual of a box fan.

Frequently Asked Questions

1. How much does it cost to run a box fan?

To calculate the cost of running a box fan, it is important to consider three things: wattage rating, electricity rate, and hourly cost.

The formula is to multiply the wattage rating by the number of hours used then divide by 1,000. After that, multiply the answer by the electricity rate.

For example, the hourly rate of a 20-inch box fan with 80 watts and an assumption of $0.10 per kWh can be calculated as:

\text{Hourly Cost} = \left( \frac{80 \, \text{watts}}{1000} \right) \times \$0.10 = \$0.008 \, \text{or} \, \$0.8 \, \text{cents}

2. How to save energy with a box fan?

To save energy using a box fan, it is important to note the following factors:

  • Choosing the Right Size – Choose a box fan that is appropriate for the size of the room. A smaller fan for a smaller room can help in saving energy.
  • Using Lower Speed Setting – Using the box fan at a lower speed setting consumes less power. Adjusting the fan to the lowest speed setting that can provide sufficient comfort is recommended.
  • Keeping the Fan Clean –Dust can hinder the performance of a box fan and increase power consumption. With this, cleaning the fan ensures optimal efficiency and power saving.

3. How much electricity does it cost to run a box fan 24/7?

To easily calculate the electricity cost of a box fan that runs 24/7, remember the simple formula – multiply the wattage by the number of hours the fan is used then divide by 1,000. After that, multiply by your kWh rate.


Box fans are quite evident in today’s households and offices which are responsible for creating airflow within indoor spaces. They are powered by electricity and typically run on standard household electrical outlets.

If you are wondering how many watts does a box fan use, it consumes an estimated 20 to 120 watts per hour. It is also important to understand that there are different factors that can influence the power consumption of a box fan.

To better understand the power consumption of a box fan and to save energy, it is critical to check the user manual and manufacturer’s specifications.

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