Domestic Air Conditioner Power Requirements

Central Air Conditioners

• Although central air conditioners are more efficient than room air conditioners, they tend to be the biggest power consumers in a summertime household. An average air conditioning system in a home uses 2,000 kilowatt-hours of electricity each year and requires a 220-volt system. That translates to 3,500 pounds of carbon dioxide and 31 pounds of sulfur dioxide. Modern units are more efficient, using 30 to 50 percent less electricity than needed for units from the 1970s. If your air conditioner is more than a few years old, you may save a lot of money by switching to a newer model due to technological innovations in efficiency.

Seasonal Energy Efficiency Ratio (SEER)

• The efficiency of central air conditioners is measured by the season energy efficiency ratio (SEER), which indicates how much energy is required for different levels of cooling. Older systems may be rated at 6 or less and are very inefficient. Air conditioners manufactured after 2006 must have a minimum SEER of 13. Look for appliances with higher SEER ratings to see the biggest savings on your energy bill. Many additional features make air conditioners efficient and comfortable, including filter light switches, fan-only switches and other monitors that keep the unit running with optimal efficiency.

Room Air Conditioners

• Some air conditioners are designed for single rooms and are often placed in a window sill to pump hot air outside. Though they use less energy than central air conditioner units due to the small area they cover, they are also less efficient. Those that use less than 7.5 amps can be plugged into any household circuit with 115 volts and 15 or 20 amps, provided there are no other major appliances on the circuit. Air conditioner units that use more than 7.5 amps need a 115-volt circuit for themselves. Even larger ones may need 230 volts.

Energy Efficiency Ratio

• The rating of energy efficiency for a room air conditioner is called the EER, or energy efficiency ratio. This is a calculation of the relationship between cooling capacity in British thermal units per hour and power input in watts. As of 2011, room air conditioners must have an EER between 8.0 and 9.8 or greater, depending on the capacity and system type. By replacing an old cooling system with a new one that has an EER greater than 10, you can often cut your cooling costs in half.