National Grid
Seasonal Advice for Spring/Summer Stay cool and save energy at the same time!
Cooling your home with central air can use almost as much energy as heating your home—so follow these tips to use energy more efficiently and better control your cooling costs.
  • Limit central air use
    • Use central air only when necessary. When the weather is cooler, use other options to cool off, such as opening windows or using a fan.
    • When you do turn on the central air, set the thermostat as high as is comfortable. The minimum recommended temperature for energy efficiency is 78°F. (A room cooled to 75°F costs 18 percent more than a room cooled to 78°F.)
    • If your air conditioner has a timer, set it to turn on the unit no more than 30 minutes before you expect to return home. That's plenty of time to make rooms cool and comfortable.

  • Keep window air conditioner units at peak efficiency
    • Remember that air conditioning can affect your energy bills as much as winter heating. Check your manual and perform regular maintenance to keep it operating efficiently.
    • Central air conditioning units should be inspected, cleaned and tuned by a professional to help them last longer and use less energy. Check with a service technician about the proper maintenance schedule.
    • Clean air filters on room air conditioners monthly. The condenser should be professionally cleaned every two years, or every year in dusty conditions.
    • Fill cracks and gaps around the air conditioner with foam weather-stripping.

  • Use a fan
    • Fans are the least expensive cooling equipment you can use.
    • Use a fan to draw in cool air at night and circulate daytime air. Install window locks so that your windows can be safely left open at night. (Of course, always keep windows closed if you have an air conditioner running.)
    • Open windows on the breezy side of the house at the bottom, and open windows on the other side of the house at the top. This creates a cooling cross-current of air.
    • A ceiling fan can provide constant breezes for increased comfort.
    • Use a fan in conjunction with air conditioners to avoid having to set the air conditioning too low.

  • Additional tips
    • When using air conditioning, shade any windows that get direct sunlight to reduce radiant heat in the room.
    • Cool things down by reducing the amount of heat generated in your house. Turn off lights when they're not needed, and avoid cooking, bathing or washing clothes during the hottest hours of the day. Use a microwave or toaster oven instead of a range.
    • If your air conditioner has an outside air option, use it sparingly. It is far more economical to recirculate and cool the indoor air than to cool the hot outside air down to comfortable room temperatures.
    • Reducing humidity will increase comfort at even warmer temperatures. Try using a bathroom exhaust fan when you shower; don’t dry firewood in your basement; don’t vent your clothes dryer inside; and put houseplants outside during the summer.
    • When buying a new air conditioner, get the right size, which may be smaller than you think. A properly sized unit cools air and removes humidity more effectively, and costs less to operate. And look for the Energy Star® label—you'll save at least 10 percent in energy costs compared to minimum-performance units.
    • If you have an attic, open the vents to let hot air escape. Without ventilation an attic can reach 150°, allowing for vapor buildup, which can lower the R-value of insulation and rot the framing of the attic.
    • If you have a kitchen door, close it when you use your oven or stove to keep heat out of the rest of the house. Open a window or door to let the heat escape.

  • Save with Energyscaping
    Landscaping not only increases the value of your home by improving its appearance, it also helps reduce seasonal costs for heating and cooling. For example, planting an evergreen windbreak to change the force and direction of the wind could save you as much as 20 percent on your home heating costs. By directing those cold winter blasts away from your house, you can reduce home heat loss and home heat costs. While trees on the north and west can help block cold winter winds, shade tress on the west and east can dramatically cut air conditioning costs.

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Related Information

Some advice for all seasons: Saving Energy on Heating and Cooling (pdf)