How to Increase Efficiency of a Central Air Conditioner

According the U.S. Department of Energy, 56 percent of your energy bill goes toward heating and cooling your home. (See Reference 1) Unless your home runs entirely on solar or wind power, the energy you use causes greenhouse gas emissions. (See Reference 5) In the summer, reduce your energy use by keeping your windows shaded and opening windows during the cooler parts of the day. If you use a central air conditioning system, make it more efficient by performing a few chores.

Change your air filter. A clogged air filter forces your unit to work harder to pull air through the system; this requires more energy and lowers your central air conditioner's efficiency. During the summer, your air conditioner's filter needs to be changed every month; at other times, check the filter every month. Once it appears dirty, change it. (See References 3 and 4) Because models vary, check your manual for instructions on how to change your filter.

Call an HVAC mechanic to inspect and tune your air conditioner once a year. It is best to do this the season before you use your central air system on a regular basis. The mechanic will check over the entire system to ensure that all parts of the unit are in good working order. A properly working air conditioner runs more efficiently than one that needs repairs. (See References 3 and 4)

Check your ducts. If your cool air seeps out of leaks in your ducts before it gets to the living areas of your home, your central air conditioner has to work longer to cool your home. Light a candle and hold it near each exposed duct joint while the unit is running; if the flame flickers, the duct has an air leak. Seal any air leaks with duct tape.

Clean around your unit and vacuum ducts. Dirt and dust build up in your ducts and on your central air conditioner reduces the unit's efficiency by making it harder to draw in air. The dirt and dust also build up on moving parts; this reduces their efficiency and damages the parts over time. Each month, use a shop vac to get inside ducts and around the unit. Once a year, hire a duct cleaning service for a more thorough cleaning. (See References 3 and 4)

Replace your central air system with a more efficient Energy Star model if it's more than 12 years old. Energy Star reports that newer models can reduce the amount of energy you use to cool your home by up to 30 percent. (See Reference 2)

Items you will need

  • New air filter
  • Candle
  • Duct tape
  • Shop vac

Tip

  • Install a programmable thermostat -- this won't make your central air conditioner more efficient, but it will save you money and save energy by adjusting the temperature as needed. The thermostat can be programmed to raise and lower your home's temperature depending on your schedule. (See References 3 and 4)

Warning

  • To avoid injury, turn your central air unit off before changing the air filter.