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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.
Carefully positioned trees can save up to 25% of a typical
household's energy for heating and cooling. Computer models from
DOE predict that just three trees, properly placed around the
house, can save an average household between $100 and $250 in
heating and cooling energy costs annually. During the summer
months, the most effective way to keep your home cool is to
prevent the heat from building up in the first place. A primary
source of heat buildup is sunlight absorbed by your home's roof,
walls, and windows. Dark-colored home exteriors absorb 70% to 90%
of the radiant energy from the sun that strikes the home's
surfaces. Some of this absorbed energy is then transferred into
your home by way of conduction, resulting in heat gain inside the
house. In contrast, light-colored surfaces effectively reflect
most of the heat away from your home. Landscaping can also help
block and absorb the sun's energy to help decrease heat buildup
in your home by providing shade and evaporative cooling.
Shading and evaporative cooling from trees can reduce the air
temperature around your home. Studies conducted by the Lawrence
Berkeley National Laboratory found summer daytime air
temperatures to be 3° to 6°F cooler in tree-shaded
neighborhoods than in treeless areas. The energy-conserving
landscape strategies you should use for your home depend on the
type of climate in which you live.
Buildings and
Trees Natural Partners
Deciduous trees
planted on the south and on the west will help keep your house
cool in the summer and allow sun to shine in the windows in the
winter. Landscaping
Tips Dependent on Geographic Area
Trees that lose their leaves in the fall (i.e.,
deciduous) are the most effective at reducing heating and cooling
energy costs. When selectively placed around a house, they
provide excellent protection from the summer sun but permit
winter sunlight to reach and warm your house. The height, growth
rate, branch spread, and shape are all factors to consider in
choosing a tree.
Vines provide shading and cooling. Grown on trellises,
vines can shade windows or the whole side of a house.
Deflect winter winds by planting evergreen trees
and shrubs on the north and west sides of your house; deflect
summer winds by planting on the south and west sides of your
house.
Orientation of the house and surrounding landscaping has a
large effect on energy consumption. A well-oriented,
well-designed home admits low-angle winter sun to reduce heating
bills; rejects overhead summer sun to reduce cooling bills; and
minimizes the chill effect of winter winds. Fences, walls, other
nearby buildings, and rows of trees or shrubs block or channel
the wind. Bodies of water moderate temperature but increase
humidity and produce glare. Trees provide shade, windbreaks, and
wind channels. Pavement reflects or absorbs heat, depending on
whether it is light or dark in color.
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Just as wearing white clothes reflects the sun's heat from your
body, a white or light-colored roof will help reflect the sun's
heat away from your home. This strategy works particularly well
when trees are located next to the reflecting surface. Not only
does the tree provide shade, it absorbs the reflected sunlight
for photosynthesis. In the process, water evaporates from the
tree, cooling the air around the house. |
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