Top 8 Most Energy Efficient Window Air Conditioners 2021

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What is the most energy efficient window air conditioner? We’ve put together a list of the 12 most energy efficient window ACs with the highest EERs and CEERs.

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 2020 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
  • Features
  • A detailed review of each model with more information than you’ll find most other places

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  • 14.7 CEER, 14,000 BTUs 
  • Cools 550-700 sq. ft.
  • Other size: 18K, 22K 

Most Efficient

Frigidaire FFRA0511R1

  • 11.1 CEER, 5,000 BTUs
  • Cools 100-150 Sq. Ft.
  • Other Sizes: 6K, 8K, 10K, 12K

Most Dependable

LG LW6017R

  • 11.3 CEER, 6,000 BTUs
  • Cools 150-250 sq. ft.
  • Thermostat With Remote Control

Most Affordable

Frigidaire FGRQ0633U1

  • 12.1 CEER, 6,000 BTUs
  • Cools 150-250 Sq. Ft.
  • Other size: 8K


Frigidaire FFRE0533U1

  • 12.1 CEER, 5,000 BTUs
  • Cools 100-150 Sq. Ft. 
  • Other sizes: 8 models from 6K-25K


Friedrich Chill CPO6G10B

  • 12.1 CEER, 6,000 BTUs
  • Cools 150-250 Sq. Ft.
  • Other sizes: 6 models from 6K-24K

Most Ecofriendly

Haier ESAQ406T

  • 12.1 CEER, 6,000 BTUs
  • Cools 150-250 Sq. Ft.
  • Dehumidify + Auto Cool  mode

Best Dehumidifying

Arctic Wind AW6005E

  • 12.0 CEER, 6,000 BTUs
  • Cools 150-250 Sq. Ft.
  • Dry-only mode

Best Value

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 accurate. A remote is included. It has a 24-hour timer with an Energy Saver function. The louvers are 2-way adjustable, so you can direct air to the right or left. An installation kit is included, so you’ll have the AC in and running in just a few minutes.

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

Refrigerant: R410A

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.

Smallest: Frigidaire FFRE0533U1 Window AC

This is an inexpensive window AC with very good features. Frigidaire, like most brands, makes basic, better and best options to meet all budgets.

This is the basic model, but it still has decent features and Energy Star efficiency. And it is rated to use just $42 per year in electricity. If your climate is cool, it will use less; if it is hot, it might use more. $42 is the average.

This is the smallest size. This model comes in every size up to 25,000 BTUs.

Size: 5,000 BTUs

Area: 100-150 square feet

Noise Range: 51-55 decibels

Refrigerant: R410A does not deplete ozone but has a global warming potential of 2,088 compared with R32, which has a 675 GWP.

Top Features: Digital controls, programmable 24-hour timer, automatic restart after a power outage and a remote control.

Additional Details: That’s a nice set of features and excellent Energy Star efficiency for such an affordable window air conditioner.

The bottom line is this: If you want to save money on the unit and on cooling costs, this offers that combination.

Most Ecofriendly: Friedrich Chill CPO6G10B AC

The Chill Series is an ecofriendly and efficient room AC with all the features you would expect from Friedrich.

This is also a very sleek and attractive AC unit that won’t look out of place in an upscale setting.

Size: 6,000 BTUs

Area: 150-250 square feet

Noise Range: N/A

Refrigerant: R32, the better choice for the environment than R410A. It does not deplete the ozone and has a global warming potential of 675 compared with 2,088 for R410A.

Top Features: It has all that you would expect. 24-hour timer, 3-speed fan including a fan-only mode for circulating the air when you don’t want it cooled. The airflow can be controlled side to side and up/down.

Additional Details: Friedrich markets their brand as an upscale brand, but it’s really quite affordable. The bottom line is that if you want good dependability, standard features and Energy Star efficiency, this unit will serve you well.

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 Value: Arctic Wind AW6005E

This is an affordable Energy Star window AC. You get high efficiency at a budget price, and that’s a good combination.

Size: 6,000 BTUs

Area: 150-250 square feet

Noise Range: 55-58 decibels depending on the fan speed. This is about 3 decibels louder than average, but not loud enough that most would notice the difference. Still, if a quiet window AC is a top priority, there are several on this list that make less noise.

Refrigerant: R410A, the same refrigerant most window and central ACs use.

Top Features: This unit has a Dry-only mode that dehumidifies without cooling. Of course it can cool too, but on damp spring or fall days when you want less humidity but not cooler air, this is the ideal mode.

This is a digital AC with LED display. It’s equipped with a 24-hour timer, energy saver function (that reduces AC amount, so it might not keep the room as cool as you would like), 3-speed fan and a full-function remote.

Additional Details: There is a lot here to like with the efficient window air conditioner for the money. The bottom line is that this affordable model is a good value.

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 individual rooms. The best bet is usually two or three smaller window units. This is especially true if one of the rooms is a home office and you want to limit noise flowing in from the rest of the home. Some try to use one large window air conditioner and multiple fans to push and pull air where they want it to go, but this adds to noise, creates trip hazards and uses quite a lot of electricity.

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.

Brand Reviews

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.

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