Small air conditioners, with around 5,000 Btu of power, are ideal for cooling spaces of 150 square feet or less. The best-rated unit in this size is the 5,200-Btu Kenmore 70051 (*Est. $160) . This is the most efficient air conditioner covered in our sources, with an energy efficiency ratio (EER) of 11.0. It's also a top performer in professional tests, earning high marks for its cooling power and noise level. Despite its relatively low price tag, this Kenmore unit offers many of the features found on high-end air conditioners, such as a remote control, sleep timer and dirty-filter indicator.
The Kenmore 70051 has close to 200 reviews from owners at Sears.com (the only site that sells Kenmore appliances), and most of them are positive. Owners say this air conditioner provides fast, efficient cooling and is easy to install. They also find it quiet, with one exception: The controls produce what multiple reviewers call an "ear-piercing" beep when they change a setting or adjust the temperature. Owners like the Kenmore's intuitive controls, but they find them hard to use in a darkened room because both the remote and the control panel itself feature small letters on a black background.
The Frigidaire FRA054XT7 (Est. $150) is also very popular with users on retail sites, including Walmart.com, Amazon.com and BestBuy.com. Owners describe this air conditioner as a great value, with good cooling performance, easy installation and a range of useful features, including a timer, remote control and an energy-saver mode. Most also say that it is reasonably quiet, although some Best Buy reviewers complain that the unit vibrates loudly against the window frame. We also saw some complaints about this model's durability, including some from users who say that their units were defective right out of the box. In professional tests, the Frigidaire does a decent job with cooling, but it's noisier than the Kenmore on both high and low speeds.