See the most efficient wall AC unit, energy efficient wall air conditioners by room size, & get insights into wall AC wattage, amperage, running costs & BTU. Plus, see how wall & window ACs compare.
Results in this article are based on a comprehensive study of over 251 wall air conditioners.
Spoilers:
 Wall AC Combined Energy Efficiency Ratio (CEER) ranges from 9.3 to 12, with 10.56 being the average;
 Wall air conditioners are not as efficient as window ACs, on average;
 One of the most highly rated and the most efficient wall AC for several room sizes is Amazon’s no. 1 best seller, the LG LT0816CER – check it out on Amazon, here;
 The wall ACs with a CEER of 12 don’t appear to be on the market anymore. The unit with the next highest CEER comes in at 11 (see details on geappliances.com, here); and
 In contrast, the most energy efficient window AC has a CEER of 15.7.
Continue reading to see the most efficient wall ACs by room size, and get insights into electricity costs, wattage, and amperage.
Plus, don’t miss the Wall AC vs Window AC performance comparison.
Energy efficient wall air conditioners
Energy efficient wall air conditioners have a CEER that ranges from 9.3 to 12.
The higher the CEER, the more energy efficient the unit.
Related: learn more about air conditioner energy efficiency, including CEER, EER & SEER.
There are currently 206 wall air conditioners that have achieved ENERGY STAR certification. These units are the most energy efficient units on the market.
The table below displays the average, most common, highest and lowest CEER from the study of these 206 efficient wall ACs.
Wall AC CEER category  CEER 
Average  10.56 
Most common  10.6 
Highest  12 
Lowest  9.3 
The average CEER for efficient throughthewall air conditioners is 10.56. However, a CEER of 10.6 is most common for wall ACs.
But which unit is the most energy efficient overall? Let’s take a look.
Most efficient wall AC unit
With a CEER of 12, the most efficient wall AC unit is the Arctic King – WWK08CW71E. The Coolworks & Arctic King (model no. MWFUK08CRN1BCL0) units also take the top spot with a CEER of 12.
These units have the highest CEER out of all 206 ENERGY STAR certified “Through the Wall” air conditioners.
These units, however, don’t appear to be on the market anymore (at least from what I can see online).
GE’s 115V BuiltIn Room AC (model no. AJCQ06LWH) is a close runner up with a CEER of 11. This unit’s specs can be seen on geappliances.com, here.
The next most energy efficient wall air conditioners have a CEER of 10.6.
A standout performer with this CEER is the highly rated, highly reviewed, no. 1 best seller on Amazon, the LG LT0816CER – check it out on Amazon, here.
However, the most energy efficient wall AC is not a case of onesizefitsall. The cooling area and the unit’s cooling capacity should be considered, in addition to CEER.
So, next, let’s take a look at how you can find the most efficient wall AC for your room.
How to find the most efficient wall AC that suits your needs
To ensure you choose the most efficient wall AC unit for your needs, follow these 3 steps:
 Work out the size of the area to be cooled, in sq. ft. Simply measure the room length and width, then multiply them together;
 Identify the recommended cooling capacity for your room, in BTU. Use the AC Room Size Chart to see the recommended BTU for your room size; and
 Find the wall AC with the highest CEER that has the appropriate cooling capacity. This can be done easily now that you know the size of the cooling area and the recommended BTU.
To help make this even easier and quicker for you, the table below lists the wall ACs with the highest CEER by BTU & recommended room size.
Most efficient wall ACs by room size & BTU
The most efficient wall ACs have a cooling capacity that ranges from 6,300 BTU to 15,400 BTU, the average being 10,434 while the most common wall AC BTU is 10,000.
These figures are based on all ENERGY STAR certified wall ACs.
Only the most efficient throughthewall air conditioners can achieve this certification.
As a result, the wall AC units listed below are the bestofthebest in terms of energy efficiency.
Note: in size ranges where there is no one standout performer in terms of CEER, the model with the lowest annual energy consumption is selected. If there still isn’t a standout model, each remaining unit is compared – the unit with the most ecofriendly related features / factors is then selected (e.g. a unit with a variable speed compressor enables greater control over energy consumption & room temperature, and certain types of refrigerant have less impact on the environment). At this point, the selection can be subjective, with eco gains being minimal, so I’d encourage you to do further research keeping your own specific needs and preferences in mind (e.g. if you need a heater too – some wall ACs offer heating functionality).
The following table lists the standout energy efficient wall ACs by room size and BTU, based on CEER.
Room size  BTU (ASHRAE) / cooling capacity range  Most efficient wall AC  Link for more details  CEER  Efficiency note 
250 sq. ft.  6,000 BTU  GE – AJCQ06LWH (6,000 BTU)  See product specs on geappliances.com, here.  11  This unit has the 2nd highest recorded CEER (which is the highest CEER available on the market today). 
300 to 350 sq. ft.  7,000 to 8,000 BTU  LG – LT0816CER (8,000 BTU)  Check it out on Amazon, here.  10.6  This is Amazon’s no. 1 best selling wall AC. However, with a CEER of 12, the Coolworks – MWFUK08CRN1BCL0 is more efficient within this range. Unfortunately, this model doesn’t appear to me to be on the market today. 
400 to 450 sq. ft.  9,000 to 10,000 BTU  LG – LT1016CER (9,800 BTU)  See price on Amazon, here.  10.6  This is the slightly more powerful version of Amazon’s no. 1 best selling wall AC. Note: the 208V version of this model consumes slightly less electricity, so if you intend to run your unit on a circuit above 115V do check it out on lg.com, here. Also, unavailable units mentioned previously with a CEER of 12 fall within this range too. 
500 to 550 sq. ft.  11,000 to 12,000 BTU  LG – LT1236CER (208V, 11,500 BTU)  Get details on Amazon, here.  10.5  This is an even more powerful version of Amazon’s no. 1 best selling wall AC. Note: this unit requires a 208V/230V supply. 
600+ sq. ft.  13,000+ BTU  Friedrich – WCT16A30A (230V, 15,400 BTU)  Check it out on Amazon, here.  9.3  Currently, this is the only ENERGY STAR certified wall mounted AC unit that caters to rooms above 600 sq. ft. 
As you can see, in general, the Combined Energy Efficiency Ratio decreases as room size / cooling capacity increases.
This demonstrates the importance of correctly matching room size with cooling capacity.
Continue reading to see how many watts wall ACs use.
The most energy efficient wall ACs cater to rooms up to 700 sq. ft. (window ACs can cool rooms that are considerably larger).
Related: Most energy efficient portable air conditioner.
Next, let’s take a look at wall AC wattage, and power consumption in general.
Wall AC wattage
Wall AC wattage ranges from 590W to 3,450W.
This is based on a combined study of 50 of the most popular wall air conditioners and 206 of the most efficient models.
There will of course be outliers, but this wattage range is typical.
The table below summarizes the results from the wall AC wattage study.
Wall AC wattage category  Wattage (W) 
Average  1,347.6W 
Most common  1,500W 
Highest  3,450W 
Lowest  590W 
Wall AC wattage refers to the maximum amount of power that the unit will use under normal operating conditions.
However, wall ACs don’t reach and continue to run at their listed wattage.
The actual amount of watts consumed varies considerably, depending on the cooling cycle, unit setting, surrounding conditions, etc.
Before we take a look at how many watts wall air conditioners use, let’s briefly list the wattage of the most efficient units to see how they compare.
The table below lists the wattage of the most efficient wall ACs by room size, covered above.
Room size  Most efficient wall AC  Link for more details  Wattage (cooling)  Amps (cooling) 
250 sq. ft.  GE – AJCQ06LWH (6,000 BTU)  See product specs on geappliances.com, here.  590W  5.5A 
300 to 350 sq. ft.  LG – LT0816CER (8,000 BTU)  Check it out on Amazon, here.  750W  7A 
400 to 450 sq. ft.  LG – LT1016CER (9,800 BTU)  See price on Amazon, here.  920W  8.5A 
500 to 550 sq. ft.  LG – LT1236CER (208V, 11,500 BTU)  Get details on Amazon, here.  1,080W  5.5A 
600+ sq. ft.  Friedrich – WCT16A30A (230V, 15,400 BTU)  Check it out on Amazon, here.  1,638W  7.5A 
As you can see, the most energy efficient wall ACs have a relatively low wattage compared to the overall wattage figures.
Related: Portable AC Wattage Results [Most Efficient Revealed], and Window AC Wattage [Most Efficient & Lowest W].
Also included in the table, for convenience, is the amperage of the efficient units.
Continue reading to see how their amperage compares with the overall amperage results.
But next, let’s take a look at how many watts wall air conditioners actually use.
How many watts does a Wall AC use?
Modern efficient wall ACs use between 49.09 watts and 141.78 watts per hour (430 kWh to 1,242 kWh per year).
The actual amount of watts consumed by wall air conditioners varies considerably.
Cooling cycle, temperature setting, speed setting, surrounding atmosphere and conditions (e.g. exposure to sunlight), among many other factors, impact the amount of watts that the unit will ultimately consume.
Note: the figures here assume typical room conditions and 750 hours per year of compressor operation (in other words, the conditions laid out by ENERGY STAR). The watt usage figures are estimated from the annual kWh figures, with the aim being to provide a more accurate power consumption figure than those that use the listed Wattage alone.
The table below lists how many watts 206 of the most efficient wall air conditioners use per hour, month and year.
Wall AC watt usage category  Watts used per hour  kWh per month  kWh per year 
Average  84.8W  61.1 kWh  742.8 kWh 
Most common  80.8W  58.2 kWh  708 kWh 
Highest  141.8W  102.1 kWh  1,242 kWh 
Lowest  49.1W  35.3 kWh  430 kWh 
The monthly and annual figures are listed in kWh (this stands for kilowatt hour), which is 1,000 watts per hour. Or, in other words, 1 watt is 0.001 kWh.
As you can see, even just within the category of most energy efficient, wall AC power consumption ranges widely.
On average, modern efficient wall ACs use 84.4W per hour, 61.1 kWh per month, and 742.8 kWh per year.
So, now that we know how many watts wall air conditioners actually use, let’s take a look at how much they cost to run.
Cost to run wall air conditioners
On average, it costs $0.013 per hour, $9.16 per month and $111.42 per year to run a wall air conditioner.
Overall, to run modern efficient wall ACs, it costs between $0.007 and $0.021 hourly, $5.30 and $15.31 monthly, and $64.50 and $186.30 annually.
This assumes a cost of 15c per kWh (the US average last year).
These figures are based on the power consumption details, along with the assumptions, listed above.
Assuming a wall AC runs at its max power continuously (i.e. at its listed wattage), it costs between $0.09 and $0.52 per hour (max) to run a wall air conditioner.
This, however, is an unlikely scenario.
Many resources online use wattage alone to estimate running costs. This inflates the estimated costs because, as mentioned, wall ACs don’t reach and continuously draw their listed wattage.
The table below summarizes the running cost results from the study of 206 modern efficient wall ACs.
Wall AC running cost category  Cost per hour (aggregated)  Cost per hour (assuming continuous max power draw)  Cost per month  Cost per year 
Average  $0.013  $0.20  $9.16  $111.42 
Most common  $0.012  $0.225  $8.73  $106.20 
Highest  $0.021  $0.52  $15.31  $186.30 
Lowest  $0.007  $0.09  $5.30  $64.50 
As you can see, wall ACs can get expensive to run.
Related: Cost To Run Window ACs [1,037+ Studied  Cheapest Revealed], and Cost To Run Portable ACs [Cheapest To Run + Calculator].
Ensuring that you are running the most efficient unit for your needs will help keep your electricity bills and carbon footprint low.
But how much does it cost to run the most energy efficient wall ACs by room size?
Let’s take a look.
The table below lists the cost to run the most efficient wall ACs by room size.
Room size  Most efficient wall AC  Cost per month  Cost per year 
250 sq. ft.  GE – AJCQ06LWH (6,000 BTU)  $5.30  $64.50 
300 to 350 sq. ft.  LG – LT0816CER (8,000 BTU)  $6.98  $84.90 
400 to 450 sq. ft.  LG – LT1016CER (9,800 BTU)  $8.54  $103.95 
500 to 550 sq. ft.  LG – LT1236CER (208V, 11,500 BTU)  $10.12  $123.15 
600+ sq. ft.  Friedrich – WCT16A30A (230V, 15,400 BTU)  $15.31  $186.30 
As you can see, the cost to run each unit increases along with room size / cooling capacity.
This further demonstrates the importance of using an appropriately powered unit for your room.
Now that we’ve covered wall AC electricity costs, let’s briefly jump back to the power consumption results and take a look at wall AC amperage.
Wall AC amps
Wall AC amperage ranges from 4.2A to 30A, with 9.7A being the average.
This is based on the manufacturer’s listed amperage for approx. 50 of the most popular wall ACs on the market.
Again, depending on the cooling cycle, unit setting, surrounding atmosphere, etc., the actual amp draw can be considerably lower.
The amp draw can also be considerably higher, albeit momentarily. On startup, ACs tend to draw 23 times their listed amperage.
The table below summarizes the wall AC amp results.
Wall AC amp category  Amps (A) 
Average  9.7A 
Most common  7.8A 
Highest  30A 
Lowest  4.2A 
For specific examples of wall AC amperage, check out the “Wall AC Wattage” section above where you’ll find the amperage of the most energy efficient wall ACs by room size.
Related: Portable AC Amps [Lowest Amp Unit Revealed], and Window AC Amps [Lowest Amp & Most Efficient Revealed].
OK, so now that we’ve covered energy efficiency and power consumption in general, let’s finally briefly compare wall AC units with window units.
Wall AC vs window AC
Window ACs outperform wall ACs.
Comparing the results from the study of wall ACs with the similar study of window ACs, we can see that window ACs are more energy efficient, and are therefore cheaper to run.
In general, window ACs outperform wall ACs while also providing more options that enable greater control over energy consumption.
Let’s take a look at some of the numbers.
The table below summarizes and compares wall ACs and window ACs performance results.
Wall AC vs Window AC category  Wall AC  Window AC 
Average efficiency (CEER)  10.56 CEER  11.96 CEER 
Most efficient unit (CEER)  12 CEER  15.7 CEER 
Cooling capacity range (BTU)  6,300 BTU – 15,400 BTU  5,000 BTU – 35,000 BTU 
Power consumption range p/y  430 kWh – 1,242 kWh  310 kWh – 2,885 kWh 
Electricity cost range p/y  $64.50 – $186.30  $46.50 – $432.75 
Wattage range  590W – 3,450W  400W – 2,425W 
Amp range  4.2A – 30A  3.8A – 20A 
Average noise level  56 dB – 65 dB  33 dB – 67 dB 
As you can see when comparing the average CEER figures (i.e. the average efficiency figures), wall air conditioners are slightly less efficient than window air conditioners.
The higher the CEER, the more efficient the air conditioner.
The most energy efficient window AC has a significantly higher CEER than its wall AC counterpart. This means that it delivers more cool air per watt consumed.
Window units also deliver wider cooling capacity and power consumption ranges compared to wall units. The wider the range, the more options are available for users to better meet their own needs, without electricity wastage.
Window ACs offer units that have lower wattage and amperage than wall ACs. This is particularly important for offgrid users.
The wattage and amperage of wall ACs can be a lot higher than window ACs. This extra power, however, doesn’t translate into larger cooling capacities due to the difference in efficiency levels.
Related: Window AC vs Portable AC [Efficiency, Cooling, Noise & More].
Finally, another important metric for AC users is noise level.
Wall ACs are louder, on average, compared to window ACs. Window ACs have an average decibel rating of 56.4 dB, which is 0.4 dB louder than the quietest wall AC identified in the study.
Final thoughts
Wall air conditioners are effective at cooling. However, window ACs can be even more effective.
If you’re undecided about which to go with, chances are window ACs will be the better option, at least in terms of performance.
There will still be cases where wall ACs are preferred. For example, it may be more convenient to replace a wall AC with another model.
I hope that the results from study into the performance of wall air conditioners helps you make a more informed decision.
And I hope that, by listing the most energy efficient wall ACs by room size, you can keep your electricity bills and carbon footprint low.
If you’re interested in reducing your bills and carbon footprint quickly and easily, don’t miss this 6 Quick Wins Cheat Sheet:

Wall AC Efficiency Results 2022 [Incl. Wall AC vs Window AC]
See the most efficient wall AC unit, energy efficient wall air conditioners by room size, & get insights into wall AC wattage, amperage, running costs & BTU. Plus, see how wall & window ACs compare.

Window AC vs Portable AC – 2022 [Efficiency, Cooling, Noise & More]
Choosing to go with a window or portable air conditioner is simple, when you have the data. Window vs portable AC – which is best? Find out here, based on data from comprehensive studies.

Cost To Run Window ACs – 2022 [1,037+ Studied  Cheapest Revealed  W/ Calculator]
How much does it cost to run a window air conditioner? See the cost to run window ACs based on 1,037+ units. Lowest cost & most efficient units are included, along with a useful calculator.