Most homeowners landscape their property purely for aesthetic reasons. Yet providing your home with a little shade has another and perhaps more consequential advantage: Landscaping may significantly reduce your energy bills. A strategically placed tree, for example, could save as much as 25 percent of a household's energy bill for heating and cooling, according to the U.S. Department of Energy's Energy Efficiency and Renewable Energy Clearinghouse (EREC).

DOE studies have indicated that simply by placing three trees around your home, you could save anywhere between $100 and $250 in heating and cooling energy costs each year. During the summer, particularly in hotter regions of the country, you may benefit by taking measures to prevent the buildup of heat before walls, windows, and your roof get the opportunity to absorb significant amounts of sunlight -- the primary reason many homeowners just can't seem to get comfortable in their own homes during the summer.

Landscaping is a natural and beautiful way to keep your home more comfortable and reduce your energy bills. In addition to adding aesthetic value and environmental quality to your home, a well-placed tree, shrub, or vine can deliver effective shade, act as a windbreak, and reduce overall energy bills. According to the DOE, dark-colored home exteriors absorb between 70 percent and 90 percent of the sun's radiant energy, which strikes surfaces in your home. A portion of that absorbed energy is then transferred into your home. Light surfaces, in contrast, manage to reflect most of the sun's heat away from your home. Trees and other forms of landscaping will further help your cause, absorbing the sun's heat while providing shade and evaporative cooling.

It comes as no surprise that tree-lined streets are indeed cooler. A series of studies conducted by the Lawrence Berkeley National Laboratory found that in tree-lined and shaded neighborhoods, average daytime temperatures were between 3 degrees and 6 degrees Fahrenheit cooler than in treeless neighborhoods. Just where trees should be placed -- and how much you and your wallet ultimately will benefit -- depends on geographical region in which you reside. In general, however, deciduous trees planted on the south and on the west keep your house cool in the summer while continuing to allow sunshine access to your home in the winter.

EREC recommends the following guidelines for landscaping with an eye toward reducing your home energy bills:

Deciduous trees -- in other words, trees that lose their leaves in the fall -- reduce heating and cooling energy costs most effectively. And when you keep them indoors, they give you the best of both worlds, serving as a gatekeeper of sorts. Indoor deciduous trees provide a barrier from the summer sun, but also permit the entry into your home of much-welcome winter sunlight, which heats your home and allows you to keep that thermostat down.

• Vines grow like wildfire on trellises. Let them go crazy; they'll shade entire windows, or even the entire side of your house, if you let them.

• Evergreen trees and shrubs planted on the north and west sides of your home serve as an effective barrier for winter winds, while evergreen trees and shrubs on your home's south and west sides deter summer winds.

• Most of us would never consider it while house-hunting, but the location of your home, as well as the position of surrounding structures and landscaping, play a significant role in how much you'll be paying to heat and cool your home each month. Builders and architects who keep this in mind design homes with three objectives for energy efficiency: to allow low-angle winter sun into the home, which cuts heating costs; to deny access to overhead summer sun, which reduces cooling costs; and to provide adequate protection from winter winds. If you've ever walked down a city street on a windy day, you're familiar with the scenario: On one street, you aren't hit with the wind, but on the next block -- where buildings aren't as high -- the wind nearly knocks you over. The same principle applies here. The more that surrounds your home (fences, walls, other homes or nearby buildings, or trees and shrubs), the more insulation you're provided. So if you're moving to a cold, blustery climate, it's time to get in the spirit of Arbor Day. In short, if you can't stand the wind, plant a tree.

• And we've all been told that to stay cool in the summer, we should wear white and avoid dark colors. The same goes for your roof. White or light-colored roofing reflects the sun's heat rays away from your home. Provide additional insurance both the comfort of your home and your wallet by planting trees near the edge of your roof. When that light is reflected from your roof, the tree absorbs it. Water then evaporates from the tree and decreases the air temperature surrounding your home.

While the last Friday in April is considered the official date for National Arbor Day, many states observe Arbor Day on different dates, according to their best tree-planting times. To find out when your state or territory observes Arbor Day, log on to the The National Arbor Day Foundation's Web site, which features a list of state and territory-specific Arbor Day dates, along with each state's official state tree.

For more information about energy-efficient landscaping for your home, check out the following Web sites and resources:

American Forests: (202) 955-4500

American Society of Landscape Architects (ASLA): (202) 898-2444

National Arbor Day Foundation (NADF): (402) 474-5655

U.S. Department of Agriculture County Extension Service (local chapter)

U.S. Department of Energy's Energy Efficiency and Renewable Energy Clearinghouse (EREC): (800) DOE-EREC (363-3732); and Network (EREN)

Published: February 26, 1998

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