A smart shopper’s guide to room air conditioners

Costing between $100 and $1,000, room air conditioners can be purchased at home improvement centers and big box retailers, and they tend to last a long time with minimal maintenance, so selecting the right model is important for maximum comfort and energy savings. Here’s what to look for:

The Energy Star label: Room air conditioners with an Energy Star rating have been deemed by the U.S. Environmental Protection Agency and the U.S. Department of Energy to use at least 10 percent less energy than comparable models. These agencies estimate that a typical consumer in hot and humid states—like South Carolina— could save up to $30 annually and as much as $250 over the life of the appliance.

A high energy-efficiency ratio (EER): EER measures the cooling capacity against the amount of electricity consumed by a window unit. National appliance standards require room air conditioners built after January 1, 1990, to have a minimum EER of 8.0. For maximum savings, get the highest EER you can afford.

Timers and programmable thermostats: These features offer better temperature control, allowing users to cool spaces according to their preferences. For example, you can set the unit to turn on 20 minutes before bedtime to make your room comfortable.

The right size for the room: Room air conditioners come in a variety of sizes. Many people buy the largest one they can afford, assuming bigger is better, but that’s a mistake. A unit that’s too large will cool a room too quickly to properly remove humidity, leaving the space feeling cool but also wet and clammy. Measure the room you need to cool, and choose an appropriate size for the job.

One last word of advice: If you’re replacing an existing unit with a more efficient model, don’t just toss the old AC in the trash pile. Air conditioners contain a refrigerant that should be removed by a trained technician. Contact your local solid waste collector for information on how to properly dispose of or recycle the old unit.