The Best Window ACs for a Cooler Summer

A window air conditioner is a solid, time-tested solution to an uncomfortably hot room or an apartment. It doesn’t take up floor space, it can easily be stored over the winter, and it’s a breeze to maintain, owing to its simple design. About all you need to do is clean its air filter occasionally. That’s nothing more than washing or vacuuming it out, blotting it dry, and sliding it back in. If you need to cool down in the months ahead, read on for our buying advice and reviews of the best a/c units from our evaluations.

Box of Cool

Several million people a year buy a window or portable air conditioner to meet their cooling needs; estimates range from about 2 million to perhaps as many as 8.5 million in any given year, according to estimates by the federal government and Statista. That’s a lot of cooling capacity. All of these appliances work by taking hot and humid indoor air and blowing it over a cold metal coil. Inside that coil is a refrigerant gas that absorbs heat like a sponge. Indoor air is also dehumidified as it’s cooled. Moisture vapor in the air condenses on the cold coil surface, drips down and runs out the back of the appliance, or it’s recycled by being thrown against the hot end of the coil, cooling it. In exchange for the electricity use to power the appliance’s refrigerant compressor and fans, you get cool and dry air.

To ensure that you get the most cooling capacity for your money, you should do two things:

1. Buy an appliance with the highest combined energy-efficiency ratio (CEER) possible. CEER is the efficiency rating that applies to window air conditioners. (Note, this is not SEER, or the seasonal energy efficiency ratio that applies to heat pumps and central air conditioning systems.) CEER expresses the ratio of cooling capacity measured in British Thermal Units (BTUs) relative to how much electricity the appliances uses to do its work; it includes the appliance's efficiency when the compressor is energized and running and when it's not running, in standby mode. A higher CEER number is better.
2. Buy an appliance with appropriate cooling capacity relative to the room size. In most cases, that means the appliance must have roughly 20 BTU of cooling capacity per square foot of room space. Measure the square feet of the room’s floor (length times width) and multiply that by 20. For example, a 20 x 15-foot room would require a small 6,000-BTU air conditioner (20 x 15 x 20 = 6,000).

How We Select

To gather the air conditioners you see here, we surveyed the market and quizzed manufacturers, as we looked for features that point to better construction quality, energy efficiency, noise reduction, simplicity of use, convenience, ease of maintenance, and versatility. That last point is important. Years ago, window air conditioners did two things. They either acted as cooling appliances or fans. They still do that, of course, but some also have dehumidifier settings for high humidity. And a bunch can even serve as heaters, which will help in the spring and fall when the weather may fluctuate, requiring supplemental heating at night but cooling during the day.

For the air conditioners we tested, we install them in a 1,200-cubic-foot space with a high ceiling. One wall of the space faces west and sees a strong and relentless afternoon sun. It gets extremely hot and stuffy, meaning it’s perfect for an air conditioner test. We run each appliance at various settings and use an infrared thermometer to measure the a/c’s effect on its surroundings, such as walls and nearby objects. Next, we measure how far away the cooling breeze can be felt. In air conditioning, this is known as throw. Most models will throw their cool air six to eight feet.

For the appliances we haven’t been able to get our hands on yet to test, we consult people we know who have used them, as well as engineers at the brands. And then we scour the specs, taking note of features that we know based on our experience can make for a good a/c, such as better-than-average industrial design or a high CEER rating.

For both tested and non-tested appliances, we look at cost but our overall effort is to select appliances in a wide range of prices and features. Our take on it is that some people want a stripped-down, less-expensive appliance while other people want bells and whistles and are willing to pay for features like voice-activated controls.

With all that in mind, here are the results from our testing and searching. We think these are the window-mounted air conditioners most ready to help you beat the heat. Scroll down to the bottom for some maintenance tips to help you keep your appliance running for as long as possible.