Our summers are getting warmer, which makes staying cool more of a challenge. If you're using a central air system, it isn't too difficult to hit your target temperature and maintain the cold air. But if you find yourself without one, the best window air conditioner is likely your best bet and keeping cool. However, choosing the right option among the plethora of window units -- especially an air conditioner matching your needs -- can be difficult.
To help solve your air conditioning troubles, CNET's Testing Lab challenged six units to see which was best at maintaining comfortable temperatures. Here are the best window AC units.
Now, let's talk testing. The process of testing window air conditioners is identical to how we tested portable AC units. First, we heated a climate-controlled room to 92 degrees Fahrenheit. Then, we turned off the heat and turned on the window air conditioner to cool mode with an auto or medium fan speed (depending on the options available) and a temperature set point of 68 degrees Fahrenheit.
We let the unit run for 2 hours and 30 minutes and repeated these steps twice to confirm our results. With the data we gathered, we looked at two main things: how consistently the AC unit maintained a temperature within 5% of 68 Fahrenheit and how consistently it kept the room within 5% of the AC unit's lowest temperature (which may or may not be 68 degrees Fahrenheit).
We then used this information to determine which units held both a 68-degree set point and their lowest temperature the longest. The second test -- which window air conditioners kept their lowest temperature the longest -- is useful if a model doesn't get to 68 degrees Fahrenheit in the 2-hour, 30-minute test window. That way, we can still assess how consistently it maintained whatever lowest temperature it did reach. A higher percentage means better performance.
Keep in mind that we didn't directly compare the performance results of the small and large units, such as the 5,000-BTU GE AHEC05AC against the 15,000-BTU Keystone KSTAW15CE. Instead, we assessed them in two categories -- the small models against one another (the FREO FHCW061AUQ, the GE AHEC05AC and the GE Profile AHTT08BC) and the three larger ones against one another (the Frigidaire FHWW103WBE, the Toshiba RAC-WK1212ESCWR and the Keystone KSTAW15CE).
In addition to performance, we also looked at other factors when arriving at our list of favorites. These included a model's features, price and other options that might add value -- or otherwise make them stand out -- beyond the test results alone.
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We put together some performance charts to make it easier to see exactly how each unit held up to our testing. In the graphic below, you'll see different charts for larger and smaller units.
The Keystone unit came in first for the larger units, maintaining a set point of 68 F for 54.3% of its run time, followed by the Toshiba unit with 35.1% and finally Frigidaire unit with 26.5%.
The GE Profile AHTT08BC dominated this test, coming in first among the smaller units with an impressive 94.7%, while the other GE unit maintained 68 degrees F for 32.5% of its run time. We aren't directly comparing the performance of the larger and smaller units, but it's worth noting that the AHTT08BC came in first overall, blowing away all of the other units with its ability to maintain a set temperature of 68 F.
In the second test -- how well each unit maintained its lowest temperature -- the results were much closer together. Among the larger units, the Frigidaire came in first with 58.9%, followed by the Keystone with 54.3% and the Toshiba with 43.7%.
The GE Profile AHTT08BC maintained its lowest temperature 61.6% of the time, while the GE AHEC05AC maintained its lowest temperature 53.6% of its runtime.
For the next set of charts, we looked at each unit's temperature changes over time.
Among the larger units, the Frigidaire, Toshiba and Keystone units followed very similar patterns as they worked toward the 68-degree set temperature.
The chart of the smaller units is more interesting, showing the GE Profile AHTT08BC getting cooler much more quickly than the AHEC05AC. The AHTT08BC got cooler faster, but it had more dramatic temperature changes. The AHEC05AC cooled more slowly but showed less overall variation.