And because noisy air conditioners can be annoying, we measure how loud each unit is on the lowest and highest settings. We also gauge how well the AC holds the set temperature. We crank the temperature in the chamber up to 90° F, then measure how long it takes the AC to lower the temperature by 15° F. We test three sizes of window ACs-small, medium, and large-and adjust the size of the chamber to the room size appropriate for each air conditioner. Read on to find out what factors you should consider when shopping for a room air conditioner, as well as details on how we test models to arrive at our air conditioner ratings.Īt Consumer Reports, we test room air conditioners in a special climate-controlled chamber. One that’s too big cools so quickly that it doesn’t have time to remove enough moisture, leaving you with a cold, clammy space. An air conditioner that’s too small will struggle to cool a room. So it’s important to choose the right unit. The typical household spends 13 percent of its annual utility bill on cooling, according to Energy Star. That’s not surprising, considering that many of us were working from home instead of in an air-conditioned office. If you’re ready to beat the heat, you aren’t alone: Almost 6 million room air conditioners were shipped for sale in 2020, an increase of almost 10 percent over the year before. For those without a central air conditioning option, room air conditioners can be an inexpensive and energy-efficient alternative for cooling one or two rooms. When the weather heats up, thoughts turn to chilling out.