Home Cooling

Energy Myth: The bigger the air conditioner the better it cools the house.

Fact: Air conditioners cool and dehumidify. An oversized air conditioner frequently cycles on and off which doesn't allow it enough time to remove moisture. A properly sized A/C will operate for a longer period of time during the hottest days which will remove uncomfortable moisture.

Home Series Booklet: Home Cooling (PDF)

No-Cost/Low-Cost Tips:

  • Reduce hot sunlight from entering the building. Close drapes and other window coverings during the day.
  • Keep the thermostat set at 78°F - or higher if using ceiling fans. Use ceiling fans to increase comfort levels at higher thermostat settings. The standard human comfort range for light clothing in the summer is between 72°F and 78°F. To extend the comfort range to 82°F, you need a breeze of about 2.5 ft/sec or 1.7 mph. A slow-turning ceiling-mounted paddle fan can easily provide this airflow.
  • Use window treatments including sun screens, reflective films and interior window treatments to reduce overheating from the sun. Also installing awnings or overhangs can reduce heat gain by as much as 90% while still letting in light. See page 4 of Home Cooling.
  • Operate your home and appliances in response to hot weather. See page 4 of Home Cooling for "Cool" Hot Weather Habits.
  • Operate ceiling fans only in occupied rooms. Fast moving air does not cool the room; it cools the person in the room. Also, in the summer, direct the fan's air downwards to cool the occupants and in winter direct the air upwards to distribute the heated air. See page 7 of Home Cooling.
  • Reduce hot humid air from entering and conditioned air from leaking out by tightening up the home. (see Home Tightening and page 5 of Home Cooling)

Investment:

  • Check attic insulation and add more if inadequate. See Home Insulation.
  • Check for adequate attic ventilation. See pages 62 through 65 of Home Energy Projects.
  • Check ductwork for leaks. Seal all air conditioner ducts, and insulate ducts that run through unheated basements, crawl spaces, and attics. See Home Heating and page 11 of Home Cooling.
  • If you have an older central air conditioner, consider replacing it with a modern, high-efficiency unit. Make sure that the outdoor unit is properly matched to the indoor unit. Arkansas is a hot, humid climate; make sure that the air conditioner you buy will adequately get rid of high humidity. Models with variable or multi-speed blowers are generally best.

    Buy a high-efficiency air conditioner. Look for a seasonal energy efficiency ratio (SEER) of 13 or higher (Starting in January 2006, 13 SEER will be the new minimum level of efficiency on the market.) Check out the EnergyStar site for qualified air conditioners.

    Make sure that the new central air conditioner is properly sized. Get assistance from an energy auditor or air conditioning contractor. A heating and cooling professional will take in to account the size of your home, orientation of the house and its windows, insulation levels, window efficiency, number of people living in home and how "leaky" the home and duct system are. Appropriate sizing of a new or replacement air conditioner is determined through a MANUAL J heating and cooling load calculation. For more information on the importance of "right sizing" go to the "Bigger is not Better" link below.

  • A high efficiency room air conditioner should have an energy efficiency ratio (EER) above 10. See page 16 of Home Cooling for sizing guidelines of room air conditioners.
  • Plant shade trees around the house. Give first priority to planting shade trees due west of west-facing windows; second priority is planting east of east-facing windows. Do not plant trees blocking the south-facing windows if you want to benefit from passive solar heating in the winter.
  • Don't use a dehumidifier at the same time your air conditioner is operating. The dehumidifier will increase the cooling load and force the air conditioner to work harder.