The Best Window Air Conditioners of 2026

Most window air conditioners look similar but they vary greatly in how they handle summer heat. The best window air conditioners cool a room quickly and quietly—without skyrocketing your monthly power bill. We’ve tested dozens of window air conditioners over the years. While most of the window AC units in our latest round of testing are 8,000-BTU air conditioners, that doesn’t mean they’re all equally as good at cooling a room.

There’s also more to a good air conditioner than cooling abilities. When testing the best window air conditioners, our rankings factor in ease of installation, noise during operation, energy efficiency, and more.

After evaluating the best window air conditioners in our climate-controlled testing labs and in real-world settings, the GE Profile Series PHC08LY (available at Amazon) is our favorite. It offers an agreeable balance of cooling performance, energy efficiency, modern tech integration, and stylish design.

Late summer might be the time when you start to get a break from the heat, but it's also one of the best times all summer to buy an AC unit. In late summer, you'll start to see some of the best window air conditioners finally go on sale. If you've been suffering through the dog days of summer, now is a good time to score a deal on a new window AC unit while you still have time to enjoy it.

Other Window Air Conditioners We Tested

How to Choose the Best Window Air Conditioner

Hot, muggy summer weather may have people without central air searching for ways to cool off. While a portable air conditioner is easier to store and typically less expensive than window ACs, these larger AC units are more efficient at handling hot air.

Here are some things to consider when buying a window air conditioner.

Cooling Capacity

BTU, a measure of an air conditioner's cooling strength, stands for British thermal unit. A BTU is the amount of heat necessary to raise the temperature of one pound of water by one degree Fahrenheit. The higher an air conditioner’s BTU rating, the more heat it can remove from the air.

Room Size

The room’s square footage should be considered when choosing a window air conditioner. The Energy Star website provides a helpful chart that shows how many BTUs per hour are needed to cool rooms of different square footage.

For example, according to Energy Star, an 8,000-BTU window air conditioner would have enough capacity to cool a room between 300 and 350 square feet, while a 5,000-BTU unit would be able to cool a room between 100 and 150 square feet.

Energy Efficiency

Most of the AC units included in this roundup are Energy Star certified. A more prestigious honor is Energy Star’s Most Efficient list.

Another thing to consider is CEER, or Combined Energy Efficiency Ratio. The higher the CEER, the more efficient a window air conditioner is. An efficient window air conditioner will save you more money on your electric bill than an inefficient model; it will also pollute less.

Noise Level

Based on the units we tested, the average window air conditioner produces about 52 decibels. At this level, most air conditioners emit a low hum, similar to a running refrigerator, which isn’t too noticeable. However, you may prefer something quieter if you are sensitive to sound or will be sitting close to the AC unit when it’s in use.

Compatibility and Installation

As the name implies, window air conditioners are designed to fit most windows. However, measuring the size of your window opening will ensure it. Also, if you have casement windows or sliders, consider an AC unit designed for those openings.

Also, consider the weight of the window air conditioners. These heavy, boxy appliances have to be installed by hand. In general, you install a window AC unit by first opening the window, resting the unit on the window sill, and lowering the window to trap the unit in place. You can then secure the unit with an included kit or a spare L-bracket.

Special Features

As air conditioners have evolved, many are Wi-Fi enabled, so you can control them with an app, Amazon Alexa, Google Assistant, or other smart devices. Other features include quiet and sleep modes, timers, and a remote control.

The Best Window Air Conditioner FAQ

What is BTU?

BTU stands for British Thermal Unit. Technically speaking, one BTU is the amount of energy it takes to raise one pound of water one degree at sea level. In practical terms, though, BTU measures an air conditioner’s ability to remove heat from the air.

Is Higher BTU Better for Window Air Conditioners?

While an air conditioner with a higher BTU rating cools more air, it doesn’t make the AC unit “better.” Other factors, such as energy efficiency, noise of operation, and installation, should also be considered when evaluating what AC to purchase.. That’s why we included these factors in our rankings.

How Do Window Air Conditioners Work?

How an air conditioner works is a frequently asked question about these devices.

An air conditioner is a machine for moving heat around. It takes heat from the air in your home and dumps it outdoors.

The window air conditioner has four major components: a compressor, a condenser, an expansion valve, and an evaporator. These have refrigerant circulating through them. The air conditioner uses these components and some fairly simple physics to move heat out of your home.

A series of basic steps keeps the heat moving in the right direction. First, the compressor pressurizes the refrigerant. Raising the pressure heats up the refrigerant and pushes it through the condenser coil. The hot condenser sits outside the window, where it sheds heat outdoors, cooling the refrigerant.

Once the cooled high-pressure refrigerant hits the expansion valve, its pressure drops. The refrigerant quickly expands and changes from liquid to gas, making it even colder. The cold refrigerant moves through the expansion coils housed in the indoor part of the window AC unit. A fan pushes warm room air across these cold expansion coils, transferring heat from the air to the refrigerant. The cooled air circulates back indoors, while the warmer refrigerant returns to the compressor and condenser, where the heat is dumped outdoors.

This refrigeration cycle continues until the room air is cool enough for the thermostat to switch off the compressor.

How Do You Clean a Window Air Conditioner?

We have a detailed breakdown of how to clean your AC, but it starts with unplugging the AC unit to avoid getting shocked.

Additionally, you will need to remove and clean the filter, remove the outer casing to mop up any moisture, dust off the fans, and wipe down the condenser coils. Cleaning the unit once doesn’t mean it’s OK to leave it indefinitely; make sure to keep your air conditioner well-maintained throughout its life.

How We Evaluated the Best Window Air Conditioners

To ensure we were fair in our evaluation, we put the window air conditioners (ranging from 5,000 to 14,500 BTU) through their paces in the same testing chamber—a custom-built, airtight room with its own window brace. We also take into account the expected cooling rate for each unit.

Performance

We install each window air conditioner in the climate-controlled room, keeping the temperature as close to 80°F as possible before turning the AC unit on at full max. We hang temperature and humidity sensors throughout the room, to determine how long it takes to cool down to 70°F—both while empty and with someone in the room.

Noise

A noisy unit can be a deal-breaker for bedroom use, so we measure the noise level at the center of the room using a decibel meter while the window units are running.

The decibel meter is set to the dBA weighting, a corrected decibel measurement that reduces the effect of low, often imperceptible frequencies, making it a more accurate measure of what the human ear perceives as loudness.

Installation, Usage, and Efficiency

In addition to collecting hard data, we evaluate the window air conditioners subjectively, including how easy it is to install, replace air filters, and understand the manual. We also account for heft, general awkwardness, ease of storage, and portability of each unit. Since no one wants an AC unit that excessively raises their power bill, we also measure power consumption.

More Articles You Might Enjoy

• The Best Portable Air Conditioners
• The Best Fans
• This powerful portable air conditioner will see you through the summer
• Your air conditioner is full of mold and bugs—here's how to clean it
• Air conditioners vs. fans: Which is right for your home?