Central air conditioners are more efficient than room air conditioners. In addition, they are out of the way, quiet, and convenient to operate. To save energy and money, you should try to buy an energy-efficient air conditioner and reduce your central air conditioner’s energy use. In an average air-conditioned home, air conditioning consumes more than 2,000 kilowatt-hours of electricity per year, causing power plants to emit about 3,500 pounds of carbon dioxide and 31 pounds of sulfur dioxide.
If you are considering adding central air conditioning to your home, the deciding factor may be the need for ductwork.
If you have an older central air conditioner, you might choose to replace the outdoor compressor with a modern, high-efficiency unit. If you do so, consult a local heating and cooling contractor to assure that the new compressor is properly matched to the indoor unit. However, considering recent changes in refrigerants and air conditioning designs, it might be wiser to replace the entire system.
Today’s best air conditioners use 30% to 50% less energy to produce the same amount of cooling as air conditioners made in the mid 1970s. Even if your air conditioner is only 10 years old, you may save 20% to 40% of your cooling energy costs by replacing it with a newer, more efficient model.
Proper sizing and installation are key elements in determining air conditioner efficiency. Too large a unit will not adequately remove humidity. Too small a unit will not be able to attain a comfortable temperature on the hottest days. Improper unit location, lack of insulation, and improper duct installation can greatly diminish efficiency.
When buying an air conditioner, look for a model with a high efficiency. Central air conditioners are rated according to their seasonal energy efficiency ratio (SEER). SEER indicates the relative amount of energy needed to provide a specific cooling output. Many older systems have SEER ratings of 6 or less.
If your air conditioner is old, consider buying an energy-efficient model. Look for the ENERGY STAR® and EnergyGuide labels — qualified central units are about 15% more efficient than standard models. New residential central air conditioner standards went into effect on January 1, 2015.
The standards do not require you to change your existing central air conditioning units, and replacement parts and services should still be available for your home’s systems. The “lifespan” of a central air conditioner is about 15 to 20 years. Manufacturers typically continue to support existing equipment by making replacement parts available and honoring maintenance contracts after the new standard goes into effect.
Other features to look for when buying an air conditioner include:
- A thermal expansion valve and a high-temperature rating (EER) greater than 11.6, for high-efficiency operation when the weather is at its hottest
- A variable speed air handler for new ventilation systems
- A unit that operates quietly
- A fan-only switch, so you can use the unit for nighttime ventilation to substantially reduce air-conditioning costs
- A filter check light to remind you to check the filter after a predetermined number of operating hours
- An automatic-delay fan switch to turn off the fan a few minutes after the compressor turns off.
For more information please visit this energy.gov with this link.