Box Fan Wattage Revealed [Data + Most Efficient Box Fan]

Last updated: February 19, 2024.

How many watts does a box fan use? See the average & get a breakdown of wattage based on fan size. Also, get the wattage of over 40 of the most popular and efficient box fans from the study (updated for 2024).

Box fans are some of the most efficient appliances for cooling. But how efficient are they, and which is the most efficient?

This article is based on a study of over 100 of the most sold box fans in the US (updated for 2024).


  • Box fan wattage ranges from 5W to 220W;
  • On average, box fans use 73W of electricity at full speed (47.3W at lowest speed, and 59.5W at medium speed);
  • 20 inch box fans consume 86.5W, on average, at full speed (approx. 56W at lowest speed, and 70.5W at medium speed);
  • Smaller box fans (i.e. those less than or equal to 10 inches) use 27W, on average. Their overall wattage range is 5W to 45W;
  • Box fan CFM ranges from 40 to 2,294 – 20 inch box fans have an average CFM of 1,750;
  • The higher the CFM per watt consumed, the more energy efficient the box fan; and
  • The standout performers from the study are the Genesis G20BOX, and the Brentwood F-20S (both are 20” box fans).

On average, box fans use 73W of electricity at full speed. Smaller box fans use 27W, while 20 inch box fans consume 86.5W on average.

The watts consumed reduces at lower speeds. Continue reading to see how many watts are used at lower speeds and get details about the most popular and most efficient box fans on the market today.

Box fan wattage image of fan grill | Eco Cost Savings

How many watts does a box fan use?

Overall, regardless of size, box fans use 73W on average at full speed. This drops to approx. 47.3W at the lowest speed setting and 59.5W at medium speed. 

The wattage of box fans varies considerably. Larger box fans operating at full speed consume substantially more watts than smaller box fans. 

For this reason, the study focused on the most popular box fan sizes and broken the results down into 3 categories: overall results, results for 20” box fans and results for box fans that are 10” or less.

The wattage for specific box fan sizes and models are detailed below. 

The most common box fan power rating identified in the research was 100W. 5W was the lowest recorded wattage, while 220W was the highest.

On average, based on research into actual power consumption at different speeds, box fans use 64.84% of its power rating at its lowest speed setting and 81.53% at its medium speed setting, if available. 

If you’re interested in the running costs, check out this article: Cost To Run A Box Fan. Spoiler: $0.011 per hour, $0.088 per night, $0.26 per day, $1.84 per week, and $8.15 per month, on average in the US, if running 24/7.

The most common box fan size recorded was 20 inches. These fans use more watts than average due to their larger size. So let’s look at results for these in isolation.

How many watts does a 20 inch box fan use?

On average, 20 inch box fans use 86.5W at full speed. At lowest and medium speeds, 20 inch box fans use approx. 56W and 70.5W, respectively.

The lowest recorded wattage in the research was Genesis’ 20″ Box Fan at 53W. The highest recorded wattage was 220W.

The most common power rating for 20 inch box fans is 100W.

The average CFM (this stands for cubic feet per minute and refers to how much air a fan moves) recorded was 1,750. This is a crucial consideration when choosing an energy efficient box fan.

Speaking of energy efficient box fans, let’s take a look at the standout models.

Most efficient box fan and editor’s choice

At 60W and with a CFM of 2,294, the Brentwood 20 in. 3-Speed Box Fan appears to be the most efficient box fan. The CFM figure was sourced from Home Depot, here

However, given lower watts used, the ratings, reviews, features and value for money, the Genesis Box Fan is recommended. Despite its very low power consumption (the lowest 20 inch box fan wattage recorded) it still achieves an above average CFM of 1,800 – more than enough for the vast majority of people.

Also, it’s very competitively priced – check out the latest price, here.

How many watts does a small box fan use?

Based on research into over 100 of the most popular box fans, smaller box fans (i.e. those less than or equal to 10 inches) use 27W on average.

The lowest recorded wattage for small box fans was 5W, while the highest was 45W.

Interestingly, the lowest wattage box fan recorded is slightly lower than the lowest recorded tower fan wattage (6W). For more details, check out the Tower Fan vs Box Fan section, here.

To see how box fans compare with ceiling fans, don’t miss the Ceiling Fan vs Box Fan section, here.

Related post: Fan Wattage, Efficiency And Cost To Run [Fan Types Compared].

Reduce electricity costs and carbon footprint

Cooling households accounts for a substantial amount of electricity consumption in the US.

EIA notes that “the residential sector’s electricity use for cooling was about 226 billion kWh in 2019, which was equal to about 16% of total residential sector electricity consumption and 6% of total U.S. electricity consumption.”

226 billion kWh is equivalent to running 41 coal-fired power plants, yearly.

The use of box fans is one of the more efficient modes of cooling. Choosing to run a box fan instead of your AC will save you money while also reducing your carbon footprint.

To reduce your electricity costs even more, consider using smaller box fans or more efficient models. Check out the electrcity cost of box fans to get 6 easy tips to reduce your costs and carbon footprint.

If you’re looking to buy a box fan consider the CFM and power consumption along with your specific requirements. 

I’ll be going with the Genesis Box Fan for my next box fan purchase as it suits my needs – cheap to run, has a lower environmental impact, it’s efficient, feature rich and has a good CFM.

For convenience, listed below is the wattage, CFM figures and links to the most popular and energy efficient box fans.

But first, let’s take a look at some frequently asked questions that were identified during the research stage of this box fan energy efficiency study.


How many amps does a box fan use?

Box fans use between 0.03 amps and 1 amp, and are generally protected by a 2.5 or 5 amp fuse.

Like any appliance with a motor, a box fan temporarily draws more power when starting up.

This increases the amp draw for a fraction of a second.

Spikes in power draw, for appliances with motors, is typically 2-3 times the listed wattage.

Note: this surge estimate is a rule of thumb for appliances with motors, so be sure to check with the manufacturer if you require exact details. Those running their box fan via a standard household outlet don’t need to be concerned about these temporary surges. This is because household circuits cater to power draw spikes.

The amp draw drops rapidly after the initial start up to reach its operating amperage.

Box fan amperage is generally listed by the manufacturer in the unit’s specs sheet.

The listed amperage is usually the max amp draw that is expected under normal operating conditions.

Box fans running at lower speeds will have a lower amp draw.

It’s also worth noting that manufacturers generally recommend operating their box fans via a standard household circuit, which is 15 amps, 110V, AC.

Running a box fan via a different power supply (e.g. DC) may void any warranty. So be sure to check the user manual beforehand.

Box Fan CFM

Box fan CFM ranges from 40 to 2,294.

Smaller box fans have a lower CFM than their larger counterparts due to their size.

20” box fans have an average CFM of 1,750.

These results are based on the manufacturer’s listed CFM figures for over 100 of the most efficient box fans. Unfortunately, however, some retailers and / or manufacturers may embellish the CFM figures.

CFM is a particularly important metric when it comes to fan efficiency.

The higher the CFM per watt consumed, the more energy efficient the box fan.

Do box fans use a lot of electricity?

No, box fans do not use a lot of electricity.

Box fans use 73W of electricity per hour at full speed, on average. This is equivalent to running a standard incandescent light bulb.

However, over time their electricity consumption will become considerable.

On average, running a box fan consumes 0.073 kWh of electricity per hour. When running 24/7, that works out to 1.752 kWh per day, 12.264 kWh per week, 54.312 kWh per month (31 days), and 639.48 kWh per year.

This assumes continuous usage at max draw, which is unlikely. But it demonstrates that box fans, over long periods of time, can consume a lot of electricity.

It depends on their level of usage.

Box fan power consumption comparisons with other standard household appliances (along with their running costs) are covered in more detail, here.

Wattage of the most popular box fans on Amazon

Box FanWatts
1Lasko #B20301 20-Inch Premium Box Fan 3-SPEED110W
2AC Infinity AXIAL 1238 (vent box fan)18W
3Comfort Zone CZ9BWT (small tabletop box fan)30W
4Comfort Zone CZ200A 20″ 3-Speed Box Fan75W
5Lasko FF305 20-inch Box Fan and Air Purifier120W
6Holmes HBF2010AWM 20″ White100W
7Holmes HBF2001DP-BM 20-Inch Box Fan100W
8Lasko 20″ Weather-Shield Performance Box Fan112W
9Optimus F-1022 (personal box fan)25W
10LASKO 20 inch Box Fan55W
11Lasko 3733 20″ Fan Box92W
12Polar-Aire S-9PB Mini Box Fan, 9″ (personal box fan)29W
13Lasko 3721 20 inch Power Plus Box Fan102W
14Genesis 20″ Box Fan53W
15Amazon Basics DK1901 3 Speed Box Fan, 20-Inch67W
16Lasko 20 Inch Box Fan55W
17Camair Bx100 High Performance Box Fan68W
18OPOLAR 8 Inch Fan (small tabletop USB box fan)5W
19Best Comfort 20″ Box Fan
20Lasko B20500 Weathershield Performance Box Fan, 20-Inch90W
21SOFASCO Cooling fan sA12038V1HSL-C (axial/exhaust box fan)32W
22CCC COMFORT ZONE 9 Inch Portable Box Fan, 9″24W
23HOLMES HBF2010AWM 20″ White 3 Speed Box Fan100W
24Lasko B20725 Metal Box Fan, 20-Inch100W
25Lasko 3743 Weather Shield Premium Plus Box Fan, 20-Inch90W
26Comfort Zone CZ10B – 10″ Portable Box Fan38W
27Brentwood Kool Zone Oscillating Fan, 30-inch100W
28Comfort Zone 20″ High Velocity Turbo Fan65W
29Uniware 8062 20 Inch Box Fan82W
30Lasko B20401 Decor Colors 20″ Box Fan55W

Source: (note: the table is not in order of popularity)

Wattage and CFM of the most sold box fans on Home Depot

Box FanWattsCFM
1Lasko 20 in. Box Fan55W1,820
2Lasko 20 in. 3-Speed Box Fan75W1,820
3Lasko 20 in. Power Plus Box Fan111W2,000
4Lasko 20 in. 3-Speed Weather Shield Performance Box Fan90W2,095
5Comfort Zone 9 in. White Box Fan with 2-Speed Front Control25W153
6Comfort Zone 20 in. White High Performance Box Fan with Carry Handle75W640
7Comfort Zone 20 in. High Performance Box Fan with Carry Handle in Black220W640
8Brentwood 20 in. 3-Speed Box Fan60W2,294
9Brentwood 20 in. Black Box Fan60W
10Impress 9 in. White Box Fan45W
11Lasko Weather-Shield Select 20 in. 3-Speed Box Fan with Thermostat100W2,195
12Lasko Premium 20 in. 3-Speed Box Fan102W2,091
13GENESIS 20 in. Black 3-Speed Settings Box Fan with Max Cooling Technology53W1,800
14Optimus 20-in. 3 Speed Box Fan75W1,850

Data source (note: the table is not in order of popularity)

While these tables don’t reflect the whole data set, I hope they are of some help with your mission to keep cool, efficiently.

Speaking of keeping cool, do you know how much it costs to run your refrigerator? Your fridge runs 24 hours a day, 365 days per year – you might be surprised by the electricity costs. Check out the cost of running a refrigerator and get 9 simple cost saving tips.

But what about the cost of running a box fan? See the hourly, daily, weekly & monthly cost to run a box fan here. There’s a useful calculator that can help you work out your own box fan running costs and also included are 6 easy tips to reduce your costs & your carbon footprint.

And don’t miss this 6 Quick Wins Cheat Sheet that’ll help you make considerable savings on your electricity bills and carbon footprint.