By looking for the ENERGY STAR signature on room air conditioners, you can easily eliminate inefficient air conditioner models that you don’t want. From there, you’ll want to pay attention to the Energy Efficiency Ratio (EER), which is used to rate the efficiency of room air conditioners. The higher the EER, the better and the more you’ll save on your utility bills.

Typically, any room AC with an EER of 10 or higher is considered efficient, but if you can afford an AC with an even higher EER, you’ll save a lot of money in the long run through your energy bills.

In DC, where humidity comes with the heat, you’ll also want to pay attention to the Sensible Heat Factor (SHF), which you want to range between 0.67 and 0.77 in order to ensure a healthy respiratory environment for you and your family. A lower SHF will help remove moisture from the air, but it will also lower your AC's efficiency, so be careful not to go too low.

For more information about efficient cooling systems, check out our Home Air Conditioning topic page.

Updated Dec. 16, 2010