Difference Between 220 & 120 Volt Air Conditioner

Of all the things you need to consider when shopping for a room air conditioner, the voltage is one of the most important.


Choose the right voltage air conditioner for your room.Choose the right voltage air conditioner for your room.
Air conditioners run on two types of electrical circuits: 120-volt, or a standard U. S. outlet, and 220-volt, a heavy-duty outlet used for larger appliances, such as clothes dryers.

BTU, or British Thermal Unit, is a thermal heat measurement. It takes one BTU to lower the temperature of 1 lb. of water in one minute. A 120-volt air conditioner typically has between 5,000 and 14,000 BTU, while a 220-volt air conditioner has 15,000 to 23,000 BTU. The BTU you need depends on the size of the room you want to cool. A very powerful 15,000 BTU air conditioning unit will not cool a 100-square-foot room better than a 5,000 BTU unit -- it will cool the room unevenly and run overly short cycles. If a 5,000 BTU air conditioner is placed in a 1,000 square foot room, it will struggle to keep it cool. Always measure the room you're cooling and use the size to determine the BTU needed.

Circuit Compatibility

A 120-volt air conditioner plugs into standard wall outlets, making them a convenient choice for most homes. A 220-volt air conditioner requires a larger three-pronged outlet for heavy-duty appliances. If you have a very large space that requires more than 15,000 BTU to cool it, you'll need to have an electrician install a 220-volt outlet. It's not possible to force a 220-volt plug into a 120-volt outlet, and it's dangerous to try.


When running cycles that are equally long, a 120-volt air conditioner and a 220-volt air conditioner are equally efficient, using roughly the same amount of energy. Both types run inefficiently if improperly placed -- 120-volt air conditioners are inefficient and use excess energy when they are placed in a room that's too large for it, and 220-volt air conditioners lose efficiency when placed in small rooms. To ensure the maximum efficiency of your air conditioner, match the BTU to the room size.


Typically, 220-volt air conditioners are larger and heavier than 120-volt air conditioners. 220-volt air conditioners for home use are either window or portable floor units, while 120-volt are available in more compact versions as well as portable versions. If you plan to move the air conditioner from room to room, a 120-volt unit will run connected to any standard outlet and is light enough to move easily once drained.

About the Author

Delaware-based Daisy Cuinn has been writing professionally since 1997, when she became the features editor for her local biweekly music newspaper. She has been a staff writer and contributor to online and offline magazines, including "What It Is!," Celebrations.com and Slashfood. Cuinn holds a Bachelor of Fine Arts from Temple University.