CEER: After each model, you’ll see its efficiency rating in CEER. This is the new energy rating. It stands for “combined energy efficiency rating” and measures the EER, or “energy efficiency rating” plus the energy the unit uses when plugged in but not running.
The 2021 Most Energy Efficient Window Air Conditioners
This is your one-stop guide to the most energy saving window air conditioners. It includes:
- Their efficiency ratings
- Sizes available
- A detailed review of each model with more information than you’ll find most other places
Ready to Buy?
If you’re in a hurry and ready to buy, click to see the price of the the energy efficient AC Units you want, and it will be on its way in a few more clicks.
Tip on Availability - Global shipping, warehousing and availability remain in flux. If the model you prefer shows that it is Currently Unavailable on Amazon, check back in a few days.
For faster delivery, choose a model from the other Most Efficient Window Air Conditioners models - they are all very good, quality and dependable units. That is why they are on the list. The experts at Pick HVAC take seriously the role of recommending the very best window air conditioners.
- 14.7 CEER, 14,000 BTUs
- Cools 550-700 sq. ft.
- Other size: 18K, 22K
- 11.1 CEER, 5,000 BTUs
- Cools 100-150 Sq. Ft.
- Other Sizes: 6K, 8K, 10K, 12K
- 11.3 CEER, 6,000 BTUs
- Cools 150-250 sq. ft.
- Thermostat With Remote Control
- 12.1 CEER, 6,000 BTUs
- Cools 150-250 Sq. Ft.
- Other size: 8K
- 12.1 CEER, 6,000 BTUs
- Cools 150-250 Sq. Ft.
- Dehumidify + Auto Cool mode
hOmelabs 6,000 BTU with Smart Control
- 12.0 CEER
- Cools up to 250 Sq. Ft.
- WiFi, Alexa, Google Assistant
Best Smart Window AC – Energy Star
Haier 14,000 BTU Smart
- 11.3 CEER – Energy Star
- Cools 700 Sq. Ft.
- Smart AC – WiFi
Most Efficient 14,000 BTU Window AC
TOSOT 8,000 BTU
- 12.1 CEER
- Up to 350 Sq. Ft.
- iFeel Remote (See full Review below)
Most Energy Efficient Window AC Reviews
Let’s take a closer look at each model on the list. Here are the most efficient window air conditioner reviews.
Most Efficient: LG LW1517IVSM AC
This is the most energy efficient window air conditioner available – by far! It allows you to cut your electric bill significantly, and it is so quiet that it won’t disrupt conversations or sleep.
Size: 14,000 BTUs
Area: 550-700 square feet
Noise Range: 44-58 decibels
Refrigerant: R32. It is better for the environment than R410A, which most window and central ACs use. Specifically, R32 has a much lower global warming potential (GWP) and does not deplete ozone.
Top Features: This series is loaded with features. It is Wi-Fi capable and works with Alexa and other smart home controllers. A 24-hour timer, energy saver and sleep modes, 4-speed fan, air exchanger, remote and auto restart after a power outage are all included.
Additional Details: It is so energy efficient because of the dual inverter compressor, which is similar to those used on mini split central ACs.
Inverter compressors run at medium capacity most of the time – rather than 100% capacity and then off, on/off, on/off and so forth. They keep capacity between about 35% and 70% most of the time. The result is less wasted cooling energy. This video gives more information.
Inverter technology also keeps temperatures more balanced and humidity levels lower – a real plus in summer heat.
These compressors are much quieter too, and this unit runs at a super-quiet 44 decibels. That’s much lower than the typical window AC unit.
Want a bigger AC that is still super-efficient? This energy efficient window air conditioner also comes in 18,000 and 22,000 BTU models. Those sizes handle areas from 700 sq. ft. to more than 1,200 sq. ft. They offer just about the same efficiency and all the same features.
The bottom line is that you’ll spend a bit more for this unit, but it will cut energy costs and keep you more comfortable from the moment you turn it on.
Most Affordable: Frigidaire FFRA0511R1 Window AC
If you want to spend as little as possible on a basic, rotary-dial (non-digital) window air conditioner, this is a very good unit. It’s dependable and inexpensive.
Size: 5,000 BTUs
Area: 100-150 square feet
Noise Range: 51.3-56.5 decibels
Refrigerant: R410A, an affordable refrigerant that doesn’t deplete ozone.
Top Features: This unit uses rotary dials rather than digital buttons and display. The unit automatically restarts when the power comes back on after an outage. The unit has a 2-speed fan and 2-way, left/right airflow adjustment.Additional Details: The bottom line is that this is a very basic window air conditioner. You save on cost, but don’t get many “bells and whistles.”
Most Dependable: LG Energy Star LW6017R AC
Those who own this hardworking little AC appreciate its reliability. You can depend on it to run problem-free for many years.
Size: 6,000 BTUs
Area: 150-250 square feet
Noise Range: 52-56 decibels
Refrigerant: R32, a newer refrigerant that is better for the environment. It doesn’t deplete ozone in the atmosphere, and it’s global warming potential rating is about 1/3 that of R410A refrigerant.
Top Features: This is a 3-speed AC with electronic digital thermostat that is very
Additional Details: Like every efficient room air conditioner on the list, this unit is Energy Star qualified.
The bottom line is that this LG Energy Star window AC unit is reasonably affordable and has a good package of features.
Quietest: Frigidaire FGRQ0633U1 Window Air Conditioner
This is a mid-range model with good features.
If you’d prefer a Wi-Fi window AC, see the next Frigidaire model, the Frigidaire FGRC. Frigidaire makes more Energy Star window ACs than any other brand. This is a basic model with excellent efficiency and enough features to keep you comfortable day and night.
Size: 6,000 BTUs
Area: 150-250 square feet
Noise Range: As low as 41db
Top Features: The list is quite impressive: 24-hour programmable On/Off timer, Energy Saver mode (but keep in mind that cooling is diminished in Energy Saver mode with ALL ACs that offer it), a mesh filter that is easy to remove and clean and a remote with temperature setting and fan-speed features.
Additional Details: The three-speed fan can be set on low to keep air near or set on medium or high push it to the far side of the room.
The bottom line is that this unit covers the basics very well and has a good track record for dependability. It won’t break the budget either.
Best Dehumidifying AC: Haier ESAQ406T
This ac unit only comes in one size, a 6,000 BTU window air conditioner.
Size: 6,000 BTUs
Area: 150-250 square feet
Noise Range: As low as 43 decibels
Refrigerant: R410A, which does not deplete ozone but has a higher global warming potential than R32. This means that if it leaks into the atmosphere, it has the potential to trap more carbon than R32.
Top Features: There are two features that stand out on this energy efficient window AC. First is the Dehumidify mode. If the air in your home is every cool and clammy, it’s nice to get rid of the humidity without making it colder. The Dehumidify mode does that by removing moisture but not turning on the AC.
Secondly, the Auto Cool mode automatically adjusts the fan speed based on the room temperature and how much cooling is needed to make it comfortable.
Additional Details: This is a digital AC that is easy to use with the digital panel and the full-function remote control. It has a 3-speed fan with Auto Cool mode. The 24-hour timer, Energy Saver and Sleep Mode round out the features.
The bottom line is that if the Dehumidify function is something you could use, there are few window ACs with it.
Best Smart Window AC – Energy Star: hOmelabs 6,000 BTU with Smart Control
Perfect for a small room when saving energy is a high priority, his hOmelabs window air conditioner will keep the space cool and comfortable with less humidity. This top window AC brand specializes in quality products with excellent energy efficiency.
Size: 6,000 BTU
Area: Up to 250 square feet
Noise Range: 52-55 decibels
Top Features: WiFi-enabled with a smart device app, works with Amazon Alexa and Google Assistant. Energy Star certified for cost savings. AC, Dry, Fan modes give you control of indoor comfort. Also Eco (energy saving) and Sleep Mode.
Additional Details: The remote is a Follow Me type – the remote senses temperature signals to the unit every few minutes, so that the AC keeps making cool air until the sensor in the remote is as cool as the thermostat setting. This ensures that the air where you are, if you have the remote with you, is properly cooled. Plus, hOmelabs makes a version of this unit in 8,000, 10,000, 12,000 and 14,500 but models, so click the link, and choose the size or sizes you need. Have smart ACs that are Energy Star rated wherever you need them!
Most Efficient 14,000 BTU Window AC: Haier 14,000 BTU Smart
Here’s another smart, Energy Star rated window air conditioner for you to consider – and it boasts a lot of cooling power for medium to large rooms. Use WiFi and the Haier SmartHQ app, Google Assistant and/or Alexa to control all the functions.
Size: 14,000 BTU
Area: Up to 700 square feet
Noise Range: 54-58 decibels
Top Features: Multiple Smart options including WiFi and Alexa, LED digital display, full-function remote, 3 cooling levels and 3 fan speeds optimize comfort.
Additional Details: It’s not easy to find a high-quality, Energy Star rated window air conditioner that is this large! It is ideal for bedroom suites, living areas and the kitchen, where cooking can heat up the space and add humidity too. This unit will keep the area cooler and drier. Ratings are excellent!
Editor’s Pick: TOSOT 8,000 BTU
This brand is made by Gree, a leading manufacturer of mini split heat pumps and air conditioners. It oozes quality as evidenced by top ratings over a large number of reviewers.
Size: 8,000 BTU
Area: Up to 350 square feet
Noise Range: 53-57 decibels
Top Features: This unit made the list due to efficiency and quality, but it boasts nice features too. The Light-touch control panel can be hard to see at first, but once you’re familiar with it, you might appreciate how it blends nicely with the front panel. The remote gives you full control over the system including swinging the airflow louvers to move air where you want it. There’s an iFeel button on the remote too, to ensure that the air where you (and the remote) are located is nice and cool.
Additional Details: What is the iFeel remote? It is like the Follow Me remote used by other brands. A sensor in the remote, the iFeel sensor, sends a signal to the unit every 10 minutes “to let it know how hard to continue running,” in order to make the space around you comfortable. Soon, all window air conditioners will have this feature. TOSOT is ahead of the crowd.
Most Efficient Window Air Conditioner Buying Guide
As you shop for an efficient window AC, here are important buying tips to keep in mind.
Efficiency Decreases as Size Increases
Most window air conditioner models come in several sizes. It’s the same with every type of AC including central air conditioners and mini split ACs.
In any AC unit model, the larger the unit is, the less efficient it is. And Energy Star takes this into consideration.
- A 10.8 CEER 6,000 BTU AC does not meet Energy Star requirements.
- A 10.8 CEER 24,000 BTU AC does meet Energy Star requirements.
Many online lists of the most energy saving window ACs are useless because they only include 5,000 and 6,000 BTU models. What if you need a larger air conditioner? The list doesn’t help! What good is an Energy Star 6,000 BTU AC designed for up to 250 square feet if you have 500+ square feet to cool? It won’t do the job. Efficiency if meaningless if the AC isn’t big enough to cool and dehumidify the space you need it for.
Our list is different. Yes, it has a lot of 6K models, but as you can see in the table above, there are many models available in larger sizes from 8,000 to 25,000 BTUs.
Note, for example, the Frigidaire FGRC Series that starts with the 6,000 BTU Frigidaire FGRC064WA1 in the table above. It has models 6K, 8K, 10K and 12K. The 6K BTU model is 12.1 CEER and Energy Star rated. The 12K model is 11.8 CEER and Energy Star rated! It wouldn’t make most lists online, but if you 450-550 square feet to cool instead of 100-250, then it will do the job where a 5K or 6K BTU unit would not.
You can always trust the pros at Pick HVAC to give you sound heating and air conditioner advice and point you to equipment that will meet your needs.
One Large Window Unit vs Several Small Units
It’s obvious that you will pay less for one large window unit than you will for two or three smaller ACs. But there is more to the issue.
The answer to this dilemma depends on your home’s floorplan.
Scenario 1 – Open Floor Plan: When airflow isn’t restricted by walls and doors, one large window air conditioner is the easy choice. The unit should have enough fan power to push cooled, dehumidified air to the furthest reaches of the space. If not, strategically placed floor plans will get the air where it needs to go when there are no walls in the way.
Scenario 2 – Closed Floor Plan: Older homes sometimes have floorplans that are less open – more
What about bedrooms? They’re a special challenge. By design, the space is closed off from the rest of the home. We recommend a small window AC for bedrooms. You can turn off the AC in the main part of the home or apartment to lower energy use and just keep the bedroom or bedrooms cool at night with one or more small, energy efficient window air conditioners.
Is a Window AC Better than Central AC?
Once you start talking about cooling the main living areas plus bedrooms and a home office, then central air conditioning must be an option. This is especially true where summers are warm and/or humid.
You can explore traditional Central Air Conditioning that uses ductwork here.
If your home doesn’t have ductwork, then a Mini Split central air conditioning and heating system should be considered. This is a good place to begin your research.
In cooler climates, there is another alternative. Do your days get warm but generally cool down in the evening and overnight? Maybe you don’t need central AC at all. A whole-house fan is an interesting consideration. These fans can fully exchange hot indoor air for cool outdoor air in just a few hours. See our Whole House Fan Guide for more information. One of these fans along with a window AC for the hottest days can reduce your equipment costs and your energy costs in cool, mostly Northern or Pacific Coast climates.
Is Higher Efficiency Worth Paying For?
The hotter your climate is, the more energy efficient your air conditioner should be. Here are the facts.
1). You will pay 15% to 30% more for an energy efficient window AC compared to one with poor efficiency.
2). The efficient unit will cut your cooling costs by 20% to 33% depending on the models being compared.
3). The hotter your climate is, the faster you will recover the 15% to 30% extra you paid for the more energy efficient unit. In cool climates, it might take 7-12 years for the payback. In warm and hot climates a payback period of 3-6 years is more common.
What about the environment? The climate is changing. Whether you believe humanity is causing it or not, we should still be good stewards of the earth. An efficient window air conditioner is a more ecofriendly option than one that isn’t very efficient.
Currently the most environmentally friendly window ACs are those with Energy Star efficiency and R32 refrigerant. The R32 is a significant step forward, cutting the global warming potential by 60% or more over R410A.
The LG LW1517IVSM, Frigidaire FGRC064WA1 and Friedrich Chill are on our Most energy Efficient Window Air Conditioner list and use R32 refrigerant.
R-32 Refrigerant vs R-410A
Which refrigerant is better in terms of efficiency and environmental friendliness?
R-32, aka R32, is a next-generation refrigerant that many of the top window air conditioner brands are starting to use.
R32 is better for the environment than R-410A. Both these refrigerants are much better than R-22 was. R-22 depletes ozone in the upper atmosphere, a major cause of thinning and loss. Britannica says, “Ozone depletion is a major environmental problem because it increases the amount of ultraviolet (UV) radiation that reaches Earth's surface, which increases the rate of skin cancer, eye cataracts, and genetic and immune system damage.” Terrible stuff.
Neither R-32 nor R-410A deplete ozone. We are all safer with these next-generation refrigerants!
But there’s another consideration called Global Warming Potential, or GWP.
R410A has a GWP of almost 2,100. The GWP of R32 is about one-third of that at 675. In short, if you buy a unit with R32, your GWP footprint will be smaller than if you choose an R410A model.
Note – Your options are limited, since R32 is just coming into wide use. You can be sure that R410A is still considered an ecofriendly refrigerant.
Get a Bigger Window AC
What does it mean when the product page of a room air conditioner says it cools, “up to 350 square feet?” Or 500 square feet, or 750 or whatever?
It means that if the room has 8-foot ceilings, isn’t a kitchen and doesn’t face a hot afternoon sun direction, then it should cool the maximum “up to” number of square feet.
But if you have 9-foot or 10-foot ceilings, the room is a kitchen where you do a lot of afternoon cooking or baking, or if the room gets really hot because it faces south or west, we have a suggestion…
Pick one or two sizes bigger than you think you need. In other words, a unit rated for “up to 350 square feet” might adequately serve 200-300 if the ceiling is high or the room is hot. So, instead of picking an 8,000 BTU unit for a 350 square foot kitchen, go with a 10,000 BTU model. If the kitchen also faces west and broils in the afternoon sun, then step up to a 12,000 BTU model. The cost difference is minimal, especially if you want to stay cool on the warmest days of the year.
Pro Tip – Keep this in mind too. If you know the kitchen is going to get hot in the afternoon (or whatever room you’re buying an efficient AC for), then turn on the air conditioner before the heat of the day. It is much harder to cool down a hot room than it is to cool a warm room – and keep it cool. The AC doesn’t have to run “all day,” but get ahead of the heat by an hour or two.
This is one area that a WiFi-enabled or smart window air conditioner comes in handy. If the unit isn’t “smart,” you’ll have to run it all day and waste energy or wait until you get home and the room is nasty hot. With a smart unit, use the app to crank up the AC an hour before you arrive home, and it should be comfortable when you get there.
What about a 24-hour programmable timer? That’s the next best thing to a smart app. But what if you forget to set the timer? You’re out of luck until you get home. With a smart AC, that is never the problem. Just pick up your phone, and turn on the COOL!
If you’d like more information before deciding on the efficient window AC unit that’ right for you, then consider our Best Window Air Conditioner Buying Guide and Reviews.
Another option is to explore brands more closely. We’ve prepared in-depth reviews on the largest brands on the market. These include:
…and others too.
If this Most Efficient Window Air Conditioner List has been helpful, please pass it along to your family, friends and followers using our social media buttons. They’re fun and easy to use! We also have other buying guides if you want to search for the Quietest Window AC or the Smallest Window AC.