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The Very Best Window Air Conditioners

Photo-Illustration: The Strategist; Photos: Retailers

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A sweltering home makes for a miserable summer. A window air conditioner can fix that, but shopping for one can be overwhelming, especially when it comes to figuring out what size and power you need for the room you’re cooling. To help you find the best window air conditioners for your space and budget, we spoke to several air-conditioner experts, who have years of experience in the AC business and have catered to everyone from homeowners to college students looking to cool dorm rooms. We also tried some units ourselves.

Jonathan Berkson, owner of SupeCoolNYC, which specializes in installing window conditioners for first-time buyers, says to always consider the size of your space and the power a potential unit will need to cool it properly, adding that performance is more important than operating cost. “The cost of operating window units has decreased dramatically over the past 20 years or so,” he says, adding: “And most all units from major brands on the market are very comparable as far as electricity usage.”

Jesse Mastro, owner of RentAnAc, a company offering air-conditioner rentals, sales, service, and installation — which also tests the newest ACs that hit the market each year — looks first to legacy brands like LG and Frigidaire that have stood the test of time. But Mastro is also a fan of several newer AC makers like Windmill, the brand behind one of the sleekest-looking window air conditioners on the market today.

Below, a breakdown of everything from BTUs to warranty length to unit size to operating options (which range from a simple dial to voice controls) so you can find the best air conditioner unit to cool things off.

What we’re looking for

BTU rating

The industry standard measurement of an air conditioner’s output of cooled air is actually a measurement of heat: the BTU, or British Thermal Unit. The higher the BTU rating of an AC unit, the larger a room it can effectively cool. Per White Mechanical Inc., to calculate a room’s AC needs specifically, first determine its square footage (length of room times width of room) then multiply that by 25, so a ten-foot-by-ten-foot or 100-square-foot room needs an AC unit rated at 2,500 BTUs or higher. Just keep in mind that halls, open doorways, and archways can all cause the effective size of the room to grow.

Noise level

According to the CDC, prolonged exposure to noise levels over 70 decibels (dB) — which is equivalent to a washing machine’s operating noise — can put some people at risk for noise-induced hearing loss. And some of the louder window AC units do indeed exceed 70 dB (roughly the equivalent to the sound inside a car cruising down the highway at 60 MPH), though often improper installation or unfilled gaps around the units are to blame. Many great window AC units operate at much quieter levels, especially at lower power settings; some are able to run at below 50 dB, which is not much louder than the hum of a refrigerator.

Warranty

Even the best window AC unit ever made is of little use if it stops working properly and is of no use if it breaks down. We factored in the many years of experience our experts have with various AC brands as well as the warranties offered by the companies themselves. And FYI, heavy use is no problem for a good unit — per PickHVAC: “A window air conditioner can run 24 hours a day, seven days a week without shortening its average lifespan. Running continuously will not cause overheating, excessive wear and tear to the unit, or any other damage that will shorten its life.”

Best air conditioner overall

BTU rating: 10,000 / Noise level: 54 dB / Warranty: 1 Year

For spaces measuring up to 450 square feet, this is an ideal window unit that’s easy to install and operate — and will last many summers. Berkson of SuperCoolNYC says that over the years, he has found “Frigidaire window units have been the most reliable,” saying this “tried-and-true brand is good over the long run.” This model measures 14.65 inches in height and is heavy but easy to install in single or double-hung windows with 18 inches of opening height and as narrow as 28 inches or as wide as 40.5 inches (no special tools needed). Control is pretty simple here too: You set the fan speed — of which there are three options — and desired temperature via remote control or on the unit itself, and there’s a timer function to use if you want the air conditioner to shut off after a given period of time. And the fan is never louder than the volume of a casual conversation, even at full power.

Best (less expensive) air conditioner overall

BTU rating: 5,000 / Noise level: 52 dB / Warranty: 1 Year

There are two things about this Frigidaire unit that are small: the price tag, and the size of space it can cool down (about 150 square feet). But if you are only concerned about one smaller room — a bedroom or office, perhaps — then this thing is just impossible to beat in terms of value. And I say that by factoring in price and reliability. “Frigidaire has stood the test of time as having the most well-built machines,” says Mastro of RentAnAc, and this one is backed by a year-long warranty from Frigidaire. You won’t find a much simpler air conditioner, as it features just two dials, one that controls fan speed (and turns it off) and one that controls the temperature. It couldn’t be easier to use, just as long as you make sure to rinse off the filter now and then.

Best smart air conditioner

BTU rating: 10,000 / Noise level: 58 dB / Warranty: 1 Year

This smart AC unit, which can be connected to your home’s wifi, is ideal for 450 square feet spaces. It runs at a pleasantly quiet 58 dB, but when it’s in “sleep mode” it goes down to 44 — about the amount of noise you’ll hear in a quiet library. RentAnAC’s Jess Mastro says: “LG makes air conditioners with excellent efficiency and noise control.” That’s thanks to dual inverter technology that uses twin rotors to blow out compressed air instead of a single fan. You can control the unit via an app (or with your voice when it’s paired with a smart-home device). It has four fan speed settings, and the dual inverter technology also helps it waste less energy.

Best easy-to-install air conditioner

BTU rating: 8,000 / Noise level: 42 dB / Warranty: 1 Year (5 years for compressor)

Energy-efficient yet powerful, this Midea AC can create an air current you can feel even up to 20 feet away. Almost literally whisper quiet at 33 decibels at a lower setting, you’ll hardly notice the Midea as it runs — save for the fact that up to 350 square feet of your home are a lot cooler. And even at its high setting, this air conditioner merely hums at 42 decibels. But, according to Robert at Lowe’s Home Improvement in Garden City, New York (who asked his full name not be used), there are two factors above all else that sell these units. First, he said they are “just so easy to install. You just snap it to the bracket and it’s set, and you can still even open the window when you want.” Second, he reported a high level of reliability based on the fact that so few units were ever returned or needed service.

Best air conditioner with heater

BTU rating: 7,500 / Noise level: 49 dB / Warranty: 1 Year

This unit not only cools your 320-square-foot space; it can warm it as well. The four-way directional air circulation spreads air or heat quickly, and at a 49-decibel operating volume, it does so quietly. This air conditioner–heater can be fit into a window opening measuring 22 inches across and just 14 inches tall, making it a great choice for apartment dwellers or for use in a bedroom or office with small windows. Do note it’s pretty heavy for a smaller unit at 66 pounds. But it’s also durable and reliable. SuperCoolNYC’s Berkson trusts LG because the brand “has invested in research and development with their units” and because “the customer service is excellent.”

Best small air conditioner

BTU rating: 6,000 /Noise level: 56 dB / Warranty: 1 Year

If you’re looking to cool a smaller space — think about 250 square feet — and want a unit you can control with an app or smart-home device, look to this energy-efficient unit from Windmill that Berkson calls “a solid choice.” That’s true for multiple reasons, the first being an affordable price tag. Second, it comes pre-assembled and ready for quick and easy installation — it can be fitted into windows with a mere 22-inch width and 13-inch opening height. And third, with three fan speeds, it can operate as quietly as 49 dB. Also, you can control the air conditioner from anywhere via its app, and it can be set to cool to a certain temperature, then shut off to save energy. If you’re the impatient type who wants a device that’s ready to use right out of the box and easy to control, too, then this is the window AC unit for you. (It’s also available in a slightly larger size, which we recommend in our Strategist Home Catalogue.)

Best large air conditioner

BTU rating: 24,000 / Noise level: 67 dB / Warranty: 1 Year 

I used an older version of this Whirlpool air conditioner for five years when my wife and I shared our first home, and it kept most of the four-room apartment quite cool without ever experiencing a single issue. It works well for the 1,500 square feet of cooling it’s rated for, provided the area is well sealed and you keep doors open (we ended up needing a second, smaller unit for the bedroom, since we shut the door at night). It’s a large piece of machinery requiring a window opening at least 30 inches wide and 19.5 inches in height, and it gets pretty noisy at 67 dB when at full crank. But it has a cooling capacity that might trick you into believing you have central air, and you can always set the fan speed lower. It’s the most expensive unit featured here today, but it’s also far and away the most powerful.

Best air conditioner to preserve the view

BTU rating: 8,000 / Noise level: 49 dB / Warranty: 1 Year

The Soleus Air Exclusive is one of only a few units using a new design of window air conditioner that preserves most of the view and light you enjoy from your window. By bridging the sill in an upside-down U shape, with the controls and cool air vents hanging inside your home and the condenser portion of the unit hanging down outside, you only lose a few inches of the window opening, yet you gain an air conditioner that can pump chilled air in as well as any other window air conditioner. That is, provided the Over the Sill Air Conditioner will work for your space, as not all windows are the same thickness — if your sill is more than 11 inches deep, in our experience, this (and other comparable over-sill options) will not fit. Likewise, some window sills are too narrow or are uneven, mounting this air conditioner may not be possible, either. If you can get it secured in place, you’ll appreciate the remote-control options, which include a 24-hour timer and a quiet sleep mode.

Our experts

• Jonathan Berkson, owner of the AC installation company SuperCoolNYC
• Jesse Mastro, founder of RentAnAC
• Steven John, founder of Dad Gear Review

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The Very Best Window Air Conditioners