To stay cool, mind what’s heating your home
Q: It’s been an awfully long winter and our heating bills were horrible. What are some things we can do to cut down on cooling costs this summer?
A: Before you start thinking of ways to save energy in hot weather, you need to think about the sources of heat that drive up your air-conditioning costs. Understanding what makes your home hot will help you prioritize strategies to efficiently cool your home.
While you may live in a well-insulated home with basic energy-saving strategies already in place, your air conditioner will still have to work very hard to remove the heat that is generated indoors, heat that comes from your home’s appliances, fans and even from people. Since skin temperature is around 90 degrees F, we give off heat to the air around us to stay cool, adding to the heat load that must be removed by the air conditioner.
Even if your home doesn’t have central air or window units, you need to be aware of the huge impact of heat generated by indoor appliances and activities so that you can use fans and other cooling strategies to stay comfortable. Studies have found that as much as one-third of a home’s annual cooling load comes from heat generated inside the house.
Obviously, when it’s time to replace any of your home’s major appliances or other electricity-using products like computers, read the EnergyGuide labels closely to compare overall energy use rather than just picking the one with the lowest purchase price.
Also, the Energy Star label is important to look for since it assures you that the product meets energy-saving standards above the minimum requirements. Refrigerators are often the biggest culprits in terms of energy use and heat generated because they are almost always located in the living part of the home and they operate 24 hours a day, seven days a week.
The next biggest source of heat gain in a home after the internal load usually comes through the windows. You’ll do the best job of keeping cool by stopping as much heat as you can before it gets inside the house, so use outdoor awnings or shutters, plant trees and shrubs near your windows, or have vines and trellises help block the direct sun. Some of the most effective home designs for helping in hot weather include big roof overhangs that block the high summer sun, and porches or screened rooms on the east and west sides of the home to help provide additional shade.
Dressing for the weather will make you more comfortable as well. Lighter-weight clothing in hot weather makes sense, of course, but it’s amazing how often I talk to people who say they really didn’t think of their choice of clothes indoors can make much of a difference in their energy needs. Surprise, folks. It can.
Of course, sitting under a ceiling fan or near a box or oscillating fan will help cool you off as well. Energy researchers typically say that the cooling breeze of a fan over your skin will allow you to turn your thermostat up three degrees or so and still maintain the comfort level you had before the fan was turned on (and every degree you can raise that thermostat when the air conditioner is on will save anywhere from 3 to 10 percent on your cooling costs).
Obviously a lot of sun comes into a home through the attic and the walls. Light-colored shingles, light-colored paint on the exterior walls, window film, and landscaping that helps shade the home can help keep the sun from getting indoors.
However, since a fair amount of heat is going to get indoors no matter what you do to stop it, you really need to work at getting rid of it. I like the solar-powered attic ventilation fans since they can dramatically drop the attic temperature by forcing hot air outdoors without using any energy to operate them. When the weather allows turning off your air conditioner, you can open windows across from each other to take advantage of cross-ventilation.
One final thought. Make sure your windows and doors seal tightly (use weatherstripping if they don’t), and caulk and seal any cracks or holes in the walls or foundation. Air infiltration (the unwanted flow of air into and out of a house) can make your home uncomfortable and expensive to cool. A well-sealed home is great protection against hot, humid air getting indoors and cooled air escaping outside.
Keep in mind that studies have found that every three kilowatt-hours of energy that you can save in your home will cut down on the need for mechanical cooling by an additional kilowatt-hour, so the savings can really add up fast.