High Efficiency Air Conditioning

If your current air conditioner is more than ten years old, now would be a good time to think about replacing it with a new high-efficiency unit. Newer air conditioners incorporate features like more efficient compressors, improved heat exchange coils and high-efficiency blowers to increase overall system efficiency and reduce energy costs. When purchasing a new air conditioner, be sure to check the efficiency rating shown on the EnergyGuide label.

Central Air Conditioners

Central air conditioners are rated with a Seasonal Energy Efficiency Ratio or SEER, which relates the air conditioner's cooling capacity to its energy consumption. The higher the SEER rating, the more cooling the unit can provide for each kilowatt-hour of electricity used. This means you can cool your home using fewer kilowatt-hours, reducing your cooling energy costs. New central air conditioners have SEER ratings ranging from 13 to 19.

Room Air Conditioners

Room air conditioners (window or wall units) are rated with an Energy Efficiency Ratio or EER. This rating is similar to the SEER used with central systems, but is based on a fixed set of conditions, while the SEER takes into account seasonal variations. Room units are available with EERs from 8.5 to 11 or higher. The higher the EER rating, the less the unit will cost to operate. Many new room air conditioners are equipped with remote controls for convenience and timers to turn the unit off after a preset interval.

Size Matters

When it comes to air conditioning, bigger is not necessarily better. The size of the unit is mainly a function of the compressor, the main energy-consuming component. The larger the compressor the more energy will be required to operate the system. An oversized unit will cycle (turn on and off) more frequently, reducing its ability to dehumidify the air. Both dehumidification and cooling are necessary for an air conditioner to provide comfortable indoor conditions during hot, humid weather. An undersized unit will operate longer and may not have the capacity to adequately cool the house to the desired temperature. When purchasing a new air conditioner, ask the contractor to perform a cooling load calculation to determine the proper size.


Just like an automobile, an air conditioner will operate more efficiently and last longer if it is properly maintained. The following guidelines will help you get the most out of your system.

  • Have the unit checked annually by a qualified service contractor - many offer an annual service contract that includes regular maintenance.
  • Replace filters regularly (check them once a month and replace when dirty).
  • Keep the outdoor condensing unit shaded from the summer sun, but be sure to allow space around the sides and top for proper air circulation.
  • Keep the manufacturer's instruction manual and other literature for future reference.

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