Room or window air conditioners cool rooms rather than the entire home or business. Since they cool a smaller space, room air conditioners are less expensive to operate than central units, even though their efficiency is generally lower. For ways to save on cooling costs with a room air conditioner, check out our Energy Saver 101 Infographic: Home Cooling.

Smaller room air conditioners (i.e., those drawing less than 7.5 amps of electricity) can be plugged into any 15- or 20-amp, 120-volt household circuit that is not shared with any other major appliances. Larger room air conditioners (i.e., those drawing more than 7.5 amps) need their own dedicated 115-volt circuit. The largest models require a dedicated 240-volt circuit.