Last updated: April 14, 2023.
How much does it cost to run a window air conditioner? See the cost to run window ACs based on a study of 1,037+ units. Lowest cost & most efficient units are included, along with a useful calculator.
Spoilers:
 On average, it costs $0.13 per hour to run a window air conditioner at maximum power.
 Overall, at max power draw, the cost to run window ACs ranges from $0.06 to $0.36 per hour, with $0.10 being the most common hourly cost.
 Based on actual power consumption tests for over 1,000 units, & assuming 750 hours per year of compressor operation under typical conditions, it costs $3.82 to $35.57 per month to run a window air conditioner. This works out to an annual cost that ranges from $46.50 to $432.75.
 Window air conditioners account for an estimated 8.2% of the average US household’s electric bill.
 Costing close to 58% less per day than average, the cheapest window air conditioner to run is the Frigidaire – FFRE053WAE (check it out on Amazon, here).
 Running this unit costs $68.32 less per year than the average cost to run a window AC (i.e. $114.82). Compared to more power hungry units, the savings can work out to as much as $386.25 per year.
Continue reading to see how much it costs to run the most energy efficient window air conditioners, by room size. Also, use the Window AC Running Cost Calculator to see how much it costs you to run your unit.
How much does it cost to run a window air conditioner?
It costs $0.06 to $0.36 per hour to run a window air conditioner, with the average being $0.13 and the most common hourly cost being $0.10.
This assumes a price per kWh of $0.15 (the US average) and also assumes continuous maximum power draw.
Window air conditioners do not operate at their maximum wattage continuously, however.
The amount of electricity window ACs draw reduces during different cooling stages, at different settings and at different room temperatures, among other factors.
The initial hour of operation tends to be the most demanding in terms of electricity, and therefore cost.
As a result, the figures summarized in the table below (and mentioned above) provide a good estimate of the cost to run a window air conditioner in the initial hour of operation.
Window AC running cost category  Cost per hour (assuming continuous max power draw) 
Average  $0.13 
Most common  $0.10 
Highest  $0.36 
Lowest  $0.06 
However, using this hourly cost to estimate how much it costs to run a window air conditioner for longer periods of time will result in inflated figures.
The actual power consumption of window ACs should be used when estimating running costs for long durations.
When testing power consumption of window units and then estimating annual energy usage, ENERGY STAR assumes 750 hours per year of compressor operation under typical conditions.
So let’s use this authoritative source to get a more accurate idea of daily, monthly and annual running cost of window air conditioners.
The table below lists how much it costs to run a window air conditioner per day, month and year, based on actual power consumption tests.
Window AC running cost category  Cost per day (based on power consumption tests)  Cost per month / 30 days (based on power consumption tests)  Cost per year (based on power consumption tests) 
Average  $0.31  $9.44  $114.82 
Most common  $0.21  $6.16  $75.00 
Highest  $1.19  $35.57  $432.75 
Lowest  $0.13  $3.82  $46.50 
These results are based on the actual power consumption of 1,037 window air conditioners and assume 750 hours per year of compressor operation under typical conditions, which is then averaged. The average price per kWh in the US (i.e. $0.15) was also used.
Based on actual power consumption tests, window air conditioners cost:
 Between $46.50 and $432.75 annually, with $114.82 being the average and $75 being the most common cost per year;
 Between $3.82 and $35.57 monthly, with the average running cost being $9.44 and the most common cost being $6.16 per month; and
 Between $0.13 and $1.19 daily, with $0.31 being the average and $0.21 being the most common running cost per day.
These aggregated figures of annual power consumption estimates (using ENERGY STAR figures) provide a more accurate running cost estimate.
Older, less efficient units will fall closer, and even above, the higher cost figures.
The hourly costs listed above are relatively high compared to these figures. This is because these figures assume a more realistic estimate of power consumption and don’t assume that the unit will run continuously all day (the assumptions are listed above).
Interestingly, the lowest cost per day to run a window AC is $0.13, which is the same as the cost to run an average window AC per hour at its max wattage.
Related: Cost To Run Portable ACs, and Cost to run wall air conditioners.
This demonstrates the importance of using an energy efficient and appropriately powered unit for your needs.
So which window air conditioner is the cheapest to run? Let’s take a look at this next, along with a more detailed look at the running costs.
Cheapest window air conditioner to run
The cheapest window air conditioner to run costs $0.13 per day, $3.82 per month, and $46.50 per year.
The Frigidaire – FFRE053WAE is the cheapest window AC to run – check it out on Amazon, here.
This energy efficient, low wattage window AC costs close to 58% less per day to run than average. Per month, this works out to $5.62 less in electricity, which is $68.32 less per year.
Compared to higher wattage units, the cost savings in electricity are even more substantial (as much as $386.25 less p/y).
Assumptions, including duration of use and kWh rate, are the same as above.
It costs just 6 cents per hour to run this unit, even at its maximum wattage of 400W.
Low wattage window ACs are cheaper to run than their more powerful counterparts. But this doesn’t mean they are as energy efficient.
Related: Window AC Wattage & Energy Efficiency [Most Efficient & Lowest W Revealed]
So, with this in mind, let’s take a look at the cost to run the most energy efficient window air conditioners, by room size.
Cost to run the most energy efficient window ACs
Based on a study of 1,037 of the best performing units, the table below lists the cost to run the most energy efficient window air conditioners by room size.
Room size  Most efficient window AC  Link for more details  Cost per month  Cost per year 
150 sq. ft.  Frigidaire – FFRE053WAE  Check it out on Amazon, here.  $3.82  $46.50 
250 sq. ft.  LG – LW6019ER  Get details on Amazon, here.  $4.48  $54.45 
300 to 350 sq. ft.  Midea – MAW08V1QWT  See this product’s clever design on Amazon, here.  $4.93  $60.00 
400 to 450 sq. ft.  GE Profile – AHTR10AC  See the latest price, here.  $5.94  $72.30 
500 to 550 sq. ft.  GE Profile – AHTR12AC  See the price, features, and more, here.  $7.20  $87.60 
600 to 650 sq. ft.  LG – LW1517IVSM  Get details on Amazon, here.  $8.80  $107.10 
700 sq. ft.  Keystone – KSTAW15CE  See this product on Amazon, here.  $11.54  $140.40 
1000 sq. ft.  LG – LW1817IVSM  Check it out on Amazon, here.  $11.32  $137.70 
1200 sq. ft.  No real standout performer  An example unit in this range can be seen on Amazon, here.  Approx. $17.95  Approx. $218.40 
1300 to 1400 sq. ft.  LG – LW2217IVSM  See price on Amazon, here.  $14.03  $170.70 
1500 to 1600 sq. ft.  LG – LW2422IVSM  Check it out on Home Depot, here.  $15.19  $184.80 
1800 to 2000 sq. ft.  Friedrich – KCL28A30A  Get details on Amazon, here.  $26.15  $318.15 
2250 to 2700 sq. ft.  Friedrich – KCL36A30A and KEL36A35A  Check them out on Amazon, here and here, respectively.  $35.57  $432.75 
For insights into the study, including how these units achieved the title of most energy efficient, check out Energy Efficient Window Air Conditioners By Room Size & BTU.
You’ll also see their CEER, BTU, wattage, and annual power consumption figures. Plus you’ll get 3 simple steps to help you choose the most energy efficient unit for your needs.
As you can see in the table above, in general, the cost to run a window air conditioner increases with room size / cooling capacity. This is because more power is required to deliver sufficient cooling capacity as the room size increases.
The monthly and annual running costs are based on power consumption tests (consumption data was sourced from ENERGY STAR).
Again, the same assumptions as above were made. This includes the kWh rate of $0.15, which is the US average.
However, you may have a higher or lower cost per kWh. If you do, check out the following Window AC Running Cost Calculator to easily work out your own specific costs.
Window AC running cost calculator
Use this Window AC Running Cost Calculator to see how much it costs you to run your window air conditioner.
Simply enter your unit’s wattage, your duration of use, and the price you pay per kWh. If needed, check out Window AC Wattage for examples.
So now that we have a good sense of how much it costs to run a window air conditioner, let’s put the costs into perspective.
Are window air conditioners expensive to run?
Window air conditioners are expensive to run.
Window AC units can cost as much as $0.36 per hour, $35.57 per month, and $432.75 per year.
Few household appliances cost more to run than window air conditioners.
To put the running costs into perspective, let’s compare window AC units with other common household appliances.
The average cost to run a window air conditioner is $0.13 per hour (assuming continuous max power draw) – this is equivalent to:
 The cost of running a TV for over 14 hours straight; or
 The cost of running a freezer for approx. 21 hours; or
 The cost of running a ceiling fan (large) for 32.5 hours.
To add more perspective, let’s look at the impact window air conditioners have on electric bills.
The average US electricity bill is $115 per month, while the average cost to run a window air conditioner is $9.44 per month (assuming 750 hours p/y of compressor operation under typical conditions).
As a result:
Window air conditioners account for approx. 8.2% of the average US household’s monthly electric bill.
While this may seem low to some, it’s actually quite high. Few household appliances account for a higher proportion of monthly bills.
Window air conditioners are energy guzzlers.
The amount of electricity window units use is similar to how much electricity microwaves use. But unlike microwaves, window ACs are used for several hours in a day.
Their high power consumption and long duration of use combine to make window air conditioners considerably expensive to run.
Stay tuned for tips on how to reduce the cost of running your window air conditioner.
Final thoughts
The cost to run a window air conditioner varies widely.
Lower wattage units cost less to run, but there’s no guarantee that they provide effective cooling.
To ensure you’re running a cost effective window AC unit, it’s important to consider energy efficiency factors such as CEER. The table above listing the most efficient units does this.
I hope that by highlighting the cost to run the most energy efficient window air conditioners by room size, you can stay cool while keeping your carbon footprint and electricity costs low.
See how these window AC running costs compare to the cost to run wall ACs, and the cost to run portable window air conditioners.
Also, don’t miss these related posts:
 Window AC Vs Portable AC [Efficiency, Cooling, Noise & More];
 Window AC Amps [Lowest Amp & Most Efficient Revealed];
 Quietest Window Air Conditioner [1,037 Studied  11 Noise Reducing Tips]; and
 Window AC Wattage [Most Efficient & Lowest Wattage Revealed].

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James, Eco Cost Savings cofounder and EditorinChief, is also our experienced inhouse energy management and sustainability expert, and manager of our network of sustainability consultants.
Before his journey into sustainability, James studied engineering. Additionally, he has experience in HVAC installation, and data analysis. A selfproclaimed practical environmentalist, and avid penny pincher, James established Eco Cost Savings to share his and his colleague’s expertise with the aim of helping to reduce energy bills and carbon footprints at scale.