Best Energy Efficient Window Air Conditioners [Summer Buyers Guide]

Best Energy Efficient Window Air Conditioners [Summer Buyers Guide]

A collection of the best energy-efficient window units available.

Thad Warren By Thad Warren

Air conditioners are funny. You never really care about your AC until it stops working. You just expect it to keep trucking summer after summer. When it doesn't. It's the bane of your existence. 

To make your life a little bit easier we analyzed the best energy-efficient window air conditioners.

Here are some of the key attributes we looked at

  • Energy Star Energy Efficiency Rating (CEER)
  • Cooling Capacity (Btu/hr)
  • Customer Ratings
  • Annual Energy Usage
  • Energy Cost
  • Price

See more details about these attributes here

Read This Before Buying

The right window unit for your home will probably depend on a combination of factors. For most people this price and size. 

You probably have a budget in mind. I’d guess you don’t know BTU numbers off the top of your head. It would be weird if you did.

Buying the correct size unit will save you money and headaches. Know what size you need before buying.

The bigger the area the more cooling capacity you will need. More capacity means more electricity usage. You are also likely to pay more for the unit. 

There is a window ac size chart by square footage at the bottom of this article

Now you have a basis for what to look for.  Let’s jump into our favorites.

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Best Overall: GE Profile - AHTR12ACH2 12,000 BTU 115-Volt Inverter Ultra Quiet Window Air Conditioner


View more Energy Star Data here

The GE Profile 12,000 BTU window ac unit is our favorite overall option. Along with being the most efficient 12,000 Btu/hr unit available it comes packed with a bunch of modern features. 

It’s wifi enabled so you can control it from your smartphone. It also connects to voice control like Alexa or Google Assistant. 

Free with the unit is the SmartHQ app which has a ton of features. These features allow you to manage your energy usage and monitor room temperature. You can create a cooling schedule, check energy usage, and set up geolocation. 

Geo-location enables the unit to automatically turn on when you are home and turn off when you leave. 

One note to think about the SmartHQ. If you choose to set up geo-location, you are essentially letting GE track everywhere you go. If that's no biggie to you then a great feature. If you’re not a fan of that, don’t use that feature.

Best Budget: Frigidaire FFRE083ZA1 8,000 BTU


View more Energy Star Data here

Our budget option does have some sacrifices. Some features, cooling capacity, and efficiency are lacking compared to the GE Profile. But it keeps you well under the $300 price point. 

It’s still Energy Star rated and provides enough cool air to keep most smaller rooms comfortable. 

It’s slightly louder than the GE Profile and doesn't have all the fancy smart home features. But it does have remote control and built-in programming controls to help you manage your energy usage. 

It even has an evening schedule mode that will keep cooling the room to a different temperature every thirty minutes. So during the day, you can keep your area warmer than slowly cool it down in the evening. 

So if you are a little more price sensitive, the Frigidaire is a good energy-efficient air conditioner. You still get useful features but lose out on all the fancy smart home stuff.

Most Energy Efficient: GE Profile - AHTR10AC*# 10,000 BTU


View more Energy Star Data here

Sustainability nerds rejoice. Behold the most energy-efficient window ac on the market. 

The GE Profile 10,000 BTU window air conditioner has the best Energy Star efficiency score of any window unit. This is measured with the Combined Energy Efficiency Ratio (CEER). 

If saving on your electricity bill and being more sustainable are important, this is the one. 

You might think this unit is bare bones, but you would be wrong. It’s actually the little brother to our best overall choice. This means you get all the fancy smart home features and the SmartHQ app. Set schedules, manage the unit from your phone, etc.

Best Cooling Capacity: LG - LW2217IVSM 22,000 BTU


View more Energy Star Data here

Ready to blow the house down? Here’s the big one. The LG 22,000 is large enough to cool 1,300 square feet. That’s a lot of cold air. 

In addition to being powerful, it also has some cool features. This unit has smart home features and an app to do all sorts of fine-tuning. 

One important note. The extra power doesn’t mean an increased noise level. Although it has extra power the LG has about the same decibel level as other smaller models. No one wants to talk over their air conditioner. 

It is a little larger than the other models on this list at 25.98 in. x 17.72 in. x 26.22in. Don’t worry it can still fit on your window sill. 

If you need even more capacity Energy Star does rate another model that has 35,000 BTUs. The Friedrich - KEL36A35A can cool over 2,000 square feet. Unfortunately, it’s relatively energy inefficient. 

Not to mention it’s an odd use case to cool that much space with a window unit. A mini split or central AC system would probably be better for most people. 

Read This Before you Buy a Window Unit

Window units are not exactly cheap. So before you drop some serious cash, you should get familiar with the different options and variables. 

Consider this when buying a window unit air conditioner

There are two big mistakes people make when buying window units. 

Big mistake number one: buying the biggest baddest window unit you can find. That will keep my house cool right!? Yes, but you're wasting money and electricity. 

A larger unit (BTU) will be less efficient than a smaller unit that will keep your area just as cool. Buying too large of a unit means more money upfront, and more money on operation. 

So before you buy check out the section below to determine the right size unit for your space. More on this below.  Jump to the AC cooling capacity per square foot chart.

Big mistake number two: buying non-variable speed units. Variable speed units are able to run at a lower power level to cool your space. 

Non-variable speed units do not. They turn on to full blast to cool or turn off completely. No in between. 

Thankfully most big brand units are variable speed. If you find some cheap knockoff, there’s a chance it’s not variable speed. Pay the extra few bucks and get a variable speed. It will pay for itself. 

Get the Right Size

  1. Determine the room's square footage - If your room is square or rectangular it’s just length multiplied by width. If it’s odd-shaped, here’s a handy dandy calculator
  2. Calculate cooling capacity - now that you know the square footage, find the correlating BTU capacity you need. See the simple chart below. 
  3. Adjust as necessary - It’s always something. If your space is in shade, or sun, or has a lot of people in it you might have to adjust. There is a little extra math below the chart to help.

Here’s a reference chart from Energy Star that breaks down square footage to needed cooling capacity. 


The above chart does have a few caveats. Here are a few things to consider in addition to the size of the area. 

  • If the area is heavily shaded, reduce capacity by 10 percent. 
  • If the room is very sunny, increase capacity by 10 percent. 
  • If more than two people regularly occupy the room, add 600 BTUs for each additional person. 
  • If the unit is used in a kitchen, increase capacity by 4,000 BTUs. Consider where you install the unit. 
  • If you are mounting near the corner of a room, make sure you can send the airflow in the right direction.

Our Research 

Our goal is to help you make an educated purchasing decision. The products we focus on in this article are based on energy efficiency data from Energy Star

We use efficiency data and pair it with other relevant data points like user reviews and prices. We then make recommendations we think will help people based on that data. We are brand agnostic. 

While we may receive affiliate commissions if you decide to purchase using one of our links. That commission does not affect the products we recommend. When new or better products are made available we update our recommendations. 

Attributes and Definitions

It’s easy to get decision paralysis if dig too deep into the data. In an effort to keep things simple and informative we focused on these variables:

  • Energy Star Energy Efficiency Rating (CEER)
  • Cooling Capacity (Btu/hr)
  • Customer Ratings
  • Annual Energy Usage
  • Energy Cost
  • Price

Energy Star Energy Efficiency Rating (CEER): 

A metric developed by the US Department of Energy to measure the efficiency of air conditioners. It’s defined as the ratio of measured cooling output (in BTU per hour) to measured average electrical energy input (in Watts) and measured standby/off-mode power consumption (in Watts.)

Cooling Capacity (Btu/hr)

BTU stands for British Thermal Unit. One Btu is the amount of heat required to raise one pound of water by one degree Fahrenheit. BTU/hr is used as a benchmark for the capacity of an air conditioning system. 

Customer Ratings

We combine ratings from multiple sources and vendors. The ratings are then compiled into one overall rating. For example, we compile reviews from Amazon, Home Depot, and Walmart to create one overall rating. 

Annual Energy Usage

The annual estimated kWh per year the unit will use. Assumes 750 hours of operation. This estimate will differ depending on your use case. You can calculate your energy usage here

Energy Cost

The estimated annual usage is multiplied by the average electricity rate in the United States as reported by the Energy Information Administration. Find your electric rate here


The price as presented by various vendors. We often use pricing from larger retailers like Home Depot and Amazon. Local and smaller vendors may have different pricing. Pricing data is updated at least once a month.