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Sometimes opening a window or running a fan is simply not enough to keep you cool in the heat. And this is to say nothing of the misery of trying to sleep in a stuffy, hot room.
If you don’t have central air at home, the best way to combat sweltering days and nights is with a window air conditioner. Window air conditioners remove hot and humid indoor air by drawing it inside the unit where it’s converted to cool, dry air that gets blown into the room while heat is dispersed outside. The process is relatively complex (see our deep dive below on how window ACs work) but the result is simple: you get a comfortable living space.
Finding a unit that satisfies your cooling needs—and fits your window—that won’t jack up your electric bill requires some research. We tested a range (and included promising models we haven’t tried yet) to find the best window air conditioners out there and help you select the right appliance.
Need other cooling solutions? Check out our picks for the best air conditioners and portable air conditioners.
The Best Window Air Conditioners
- Best Overall: LG LW1517IVSM Window Unit
- Best Value: Frigid FFRA051WAE Window Air conditioner
- Quietest: Midea MAW12V1QWT
- Easiest to Set Up: July Window Air Conditioner
- Best Features: Windmill Smart Inverter Window Air Conditioner
How Do Window Air Conditioners Work?
Window air conditioners use motor-driven fans to pull hot, moist indoor air over a metal tube coil with cold refrigerant gas inside. The heat energy in the room passes through the metal coil into the cold refrigerant inside. Then the appliance’s compressor draws the heated gas to a coil on the back of the appliance, converting the gas into a liquid. Another motor-driven fan blows outdoor air over this hot, liquid-filled coil and discharges the heat to the outdoors. In exchange, you get cool and dry air pumped inside.
Equally important in the cooling process is dehumidification. In the summer, there’s a lot of moisture vapor suspended in the air, and in order for you to feel more comfortable, the air conditioner has to remove it.
The moisture vapor in the indoor air condenses on the coil’s cold surface. This water drips down to the back of the appliance and runs out through a drain. Alternatively, the fan on the back picks it up and throws it against the hot coil, where it’s converted back to moisture vapor and discharged outside with the hot air. The cooling process is identical among various window air conditioners. However, the appliance’s cooling capacity, features, and controls differ.
For advice on how to clean your air conditioner, read our primer following reviews.
What to Consider
Energy Efficiency
Look for a window air conditioner with a high Combined Energy-Efficiency Ratio rating. CEER is the efficiency rating that applies to window air conditioners. (Note: This is different from SEER, or Seasonal Energy-Efficiency Ratio, which applies to heat pumps and central a/c systems.) The higher the rating the better.
The CEER number expresses the ratio of cooling capacity, measured in British Thermal Units (BTUs), relative to how much electricity the appliance uses to cool the space. It includes the appliance’s efficiency when the compressor is energized and running and when it’s not running, in standby mode. A few air conditioners still retain the older (but still valid) EER efficiency number, and the same rule applies—a high EER is better than a low one
The window air conditioner you choose must have roughly 20 BTUs of cooling per square foot of room space. Measure the square feet of the room’s floor and multiply that by 20. For example, a 20-by-15-foot room would require a small, 6,000-BTU air conditioner.
Controls and Features
Window air conditioners are no different from other appliances regarding programming and controls. Controls range from simple knobs to buttons to touch-activated electronic panels similar to microwaves or washing machines. Some window air conditioners have handheld remotes or employ smartphone apps for controls.
More expensive window air conditioners are typically more fully featured. Some are equipped with a dehumidification setting for dealing with extra moist air, a heater, a fan to use without cooling, and timers that allow you to slowly back off the cooling output at night as you fall asleep.
Some smarter appliances can even ramp back up, cooling your room again toward dawn. Others have smartphone features that allow you to control your unit from afar and geofencing that automatically turns the unit on when your phone comes within a radius of your home.
How We Tested
We surveyed the market for units with great construction quality, energy efficiency, noise reduction, simplicity of use, convenience, ease of maintenance, and versatility. We tested several of the window air conditioners we recommend by installing them in a 1,200-cubic-foot space with a high ceiling, a small two-bedroom apartment, and a bedroom/office in a one bedroom apartment.
We ran each appliance at various settings and used an infrared thermometer to measure the AC’s effect on its surroundings, such as walls and nearby objects. Next, we measured how far away the cooling breeze could be felt, known as throw. Most models we recommend throw cool air six to eight feet. For the appliances we haven’t tested, we consulted engineers at the manufacturers, scoured the specs, noted features, and considered user reviews and compared that with our extensive experience using and installing window air conditioners.
Pros
Multi-speed compressor conserves energy- Quiet operation
- Comes ready with insulated panels
- Wi-Fi enabled
Cons
- App doesn’t always work reliably
This LG uses a multi-speed compressor to control cooling, speeding up and slowing down to maintain the desired temperature. While most window units don’t use this method, we found the adaptable dual-inverter design from LG a great way to keep the room temp steady.
It’s pretty quiet, too, with a sleep mode that quiets the motor at night so you can get better rest. This window unit won best overall compared to all of the other window and portable units we tested because of its ease of use, efficiency, and quiet operation.
Best of all, LG includes insulation for keeping cold air in and warm air out—a notorious drawback of most window units.
Key Specs
| Cooling Area | 800 sq ft. |
|---|---|
| BTUs | 14,000 |
| CEER | 14.7 |
| Dimensions | 23.5 x 29 x 15 in. |
Pros
- Washable filter is easy to clean
- Simple controls
Cons
- No smart features or timer
The Frigidaire is a low-effort, high-efficiency air conditioner designed to cool off a small, stuffy space quick.
It has a simple two-knob control system. The top knob controls the cooling setting, the bottom knob controls fan speed, and you have the option to run the fan with or without cooling. The appliance’s thermostat cycles the air conditioner on and off to keep the temperature within range based on the temperature you set with the top knob.
There’s no smart functionality so it can only be controlled from the knobs. Still, it’s an efficient window unit that won’t hurt your wallet and its washable filter saves you money on having to buy replacements.
Key Specs
| Cooling Area | 150 sq ft |
|---|---|
| BTUs | 5,000 |
| CEER | 11 |
| Dimensions | 21.6 x 18.6 x 12.4 in. |
Pros
- Extremely quiet operation
- Unique design better isolates compressor
- Distributes air vertically
- Easy to clean
Cons
- Installation is a bit complicated
The whisper-quiet operation of this quality AC unit isn’t it’s best feature, and that’s saying a lot since this was the quietest of the lot we tested. Even better than its hushed noise level is the U-shaped mounting, which lets you fully close your window between indoor and outdoor sections of the unit.
It’s the sort of design that makes you ask why all window AC units aren’t like this—but alas, this unit does require a special mounting bracket to work correctly.
This inverter compressor AC unit uses multi-speed, like the LG we deemed best overall, but this has automatically swinging louvers to distribute air even better.
Key Specs
| Cooling Area | 550 sq ft. |
|---|---|
| BTUs | 12,000 |
| CEER | 15 |
| Dimensions | 9 x 21.5 x 13.5 in. |
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Pros
- Wi-Fi enabled
- Sleek design
- Can be operated with included remote or smart phone
Cons
- Vents aren’t adjustable
The July unit is sleek, customizable, and can be setup in less than 20 minutes. It comes with a bracket, with insulating wings included, that screws into the window. After that’s installed, you simply slide the air conditioner in and it’s ready to go.
The control panel is located on top of the unit rather than on the front so it’s more comfortable to operate than having to crouch down to see which button does what—a minor but appreciated design note. You can also control the unit from the straightforward app to change modes, fan speed, and schedule automatic on and off time. There’s a remote control included so you can choose which to use. We used the app to turn on the A/C before getting home but used the remote when actually in the apartment.
The unit is quiet on its lowest setting and on high sounds like a dryer behind a closed door—noticeable at first, but muffled enough that you don’t have to turn up the T.V. volume.
Another huge plus is that it fits smaller windows. We installed it in a very small corner window of a living room that couldn’t house pretty much any other standard sized unit. The July fit perfectly without the insulating wings.
Key Specs
| Cooling Area | 250 sq ft. |
|---|---|
| BTUs | 6,000 |
| CEER | 11 |
| Dimensions | 17.9 x 19.9 x 14.8 in. |
Pros
- Quiet operation
- Intuitive app
- Built-in voice command
Cons
- Insulating wings could be better
Windmill’s unit comes equipped with the features you’d expect from its modern design—Wi-Fi and smart home-compatibility, ease of installation—with the added convenience of built-in voice command.
Instead of shooting air straight out, its vents are on top of the unit to shoot up and outward for better circulation overall. It’s also one of the quietest models we tested so it’s great for light sleepers. It includes insulated wings though they aren’t on par with the quality of the unit and we added some extra insulation.
The app is also very intuitive. Like the unit itself, the app is well thought-out and well designed making it easy to set the Windmill to eco mode or set the fan and cooling settings.
Key Specs
| Cooling Area | 350 sq ft. |
|---|---|
| BTUs | 8,000 |
| CEER | 11.6 |
| Dimensions | 13.2 x 19.3 x 19.4 in. |
6
Best for Medium-Sized Rooms
LG LW6017R Window Air Conditioner
Pros
- Plenty of features
- Solid dehumidifier
- High-performance and fast-acting
Cons
- Build quality is lacking
This high-performance, 6,000-BTU LG window air conditioner is designed to cool medium spaces quickly, ideal for rooms up to 10 by 25 feet. Its many features include an energy-saver mode, a 24-hour on/off timer, a full-function remote control, three cooling speeds, three fan speeds, and an auto reset that turns the unit back on once power is restored after a power outage.
When indoor air humidity is high, this air conditioner has powerful dehumidifying abilities to keep you from that sticky feeling.
Key Specs
| Cooling Area | 250 sq ft. |
|---|---|
| BTU | 6,000 |
| CEER | 12 |
| Dimensions | 14.9 x 19.4 x 12.4 in. |
| Weight | 49.9 lbs. |
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Pros
- Straightforward operation
- Quick cooling
- Lightweight
Cons
- Loud
This Amana air conditioner is the very definition of low-cost cooling. (It seemed to us as much a time machine as a cooling machine—the two-knob simplicity and familiar hum was enough to transport me back to my first stuffy apartment and the simple little air conditioner in it—and that was more than 40 years ago.)
Call the little AMAP050BW a fancy version of an ice block and a fan. Turn its dial to the large snowflake setting and the dial to number seven (maximum chill and maximum fan speed) and you’ve got cold air filling the space in a couple of minutes.
We detected no rattles, but can we say this is whisper-quiet cooling? No. But it’s not annoying, either. If you’re a light sleeper, you might need earplugs. Then again, you may find comfort in the steady white noise it produces.
As for maintenance, the air filter slides out to the right—a simple and welcome feature that eases cleaning.
Key Specs
| Cooling Area | 350 sq ft. |
|---|---|
| BTU | 8,000 |
| CEER | 11 |
| Dimensions | 16 x 15.5 x 12.5 in. |
| Weight | 39.7 lbs. |
How to Clean Your AC Unit
To maintain your AC, the best thing you can do is regularly vacuum the air filter. If it’s really grubby, give it a light scrubbing with water and dish detergent, and rinse it clean. Always let the filter dry before reinstalling it.
It’s not uncommon for a couple of fins on the air conditioner’s back to get mashed or bent as you’re handling the appliance. To straighten them, use the edge of a plastic putty knife or credit card. Insert the knife or card into a space above the bent fin, and slide it down to the bent area. If the fins are severely bent, use a fin straightener tool.
If your AC starts to let out a rattle, investigate. It could be anything from a rough window sill to a wobbly pane. Should the sound be too much, foam insulation strips and sound-dampening rubber sheeting can help quiet the noise.
Most of the air conditioners here operate very comfortably on a 15-amp branch circuit (a branch circuit consists of all the wiring and devices that hook up to a single circuit breaker or fuse). These circuits support up to, naturally, 15 amps of current draw. If the AC runs at 6 amps, the circuit still support another 9 of current.
However, even an energy-efficient air conditioner draws a substantial amount of current–sometimes two or three times the amperage it usually runs at—when its condenser turns on to pump its refrigerant through its closed loop. This may cause the circuit breaker to trip.
If that happens, look around to see what other loads are operating on the circuit. Maybe somebody’s running a vacuum cleaner or other high-current appliance. Shutting down other loads frees up electrical capacity and allow the air conditioner to run as it should.
Danny Perez
Commerce Editor
Danny Perez is a Commerce Editor for Popular Mechanics with a focus on men's style, gear, and home goods. Recently, he was coordinator of partnership content at another product journalism outlet. Prior to that, he was a buyer for an independent men's shop in Houston, Texas, where he learned all about what makes great products great. He enjoys thrifting for 90s Broadway tees and vintage pajama sets. His spare time is occupied by watching movies and running to impress strangers on Strava.
Roy Berendsohn
Senior Home Editor
Roy Berendsohn has worked for more than 25 years at Popular Mechanics, where he has written on carpentry, masonry, painting, plumbing, electrical, woodworking, blacksmithing, welding, lawn care, chainsaw use, and outdoor power equipment. When he’s not working on his own house, he volunteers with Sovereign Grace Church doing home repair for families in rural, suburban and urban locations throughout central and southern New Jersey.
Kevin Cortez
Commerce Editor
Kevin Cortez is an editor for Runner's World, Bicycling, and Popular Mechanics covering reviews. A culture and product journalist for over ten years, he’s an expert in men’s style, technology, gaming, coffee, e-bikes, hiking, gear, and all things outdoors. He most recently worked as the Style Editor for Reviewed, a top product recommendation site owned by USA TODAY. He also helped with the launch of WSJ's Buy Side commerce vertical, and has covered the music and podcast industries for Mass Appeal, Genius, Vulture, Leafly, Input, and The A.V. Club. Equally passionate about leisure as he is his penmanship, Kevin dedicates his spare time to graphic novels, birding, making cold brew, and taking long, meandering walks.
