Landscaping For Energy Savings
Are you looking for cost-effective yet eye-pleasing ways to
lower your
energy bills? Planting trees, shrubs, vines, grasses, and
hedges could
be the answer to energy savings. In fact, landscaping may be your best
long-term
investment for reducing heating and cooling costs, while
also bringing
other improvements to your community.
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 increase overall energy savings.
A well-designed landscape will:
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Cut your summer and winter
energy costs dramatically.
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Protect your home from winter wind and summer sun.
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Reduce consumption of water, pesticides, and fuel for
landscaping and
lawn maintenance.
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Help control noise and air pollution.
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Landscaping Saves Money Year-Round
Carefully positioned trees can save up to 25% of a
household's energy consumption for heating and cooling. Computer models devised
by the U.S. Department of Energy predict that the proper placement
of only three trees will save an average household between $100 and
$250 in energy costs annually.
On average, a well-designed landscape provides enough
energy savings to return your initial investment in less than 8
years. An 8-foot(2.4-meter) deciduous (leaf-shedding) tree, for example,
costs about as much as an awning for one large window and can ultimately
save your household hundreds of dollars in reduced cooling costs,
yet still admit some winter sunshine to reduce heating and lighting
costs. Landscaping can save you money in summer or winter.
Summer
You may have noticed the coolness of parks and wooded areas compared to the temperature of nearby city streets. Shading
and evapotranspiration (the process by which a plant actively
moves and releases water vapor) from trees can reduce surrounding air temperatures as much as 9 degrees F (5 degrees C). Because
cool air settles near the ground, air temperatures directly under
trees can be as much as 25 degrees F (14 degrees C) cooler than air
temperatures above nearby blacktop. Studies by the Lawrence Berkeley
Laboratory found summer daytime air temperatures to be 3 degrees F to 6degrees F (2 degrees C to 3 degrees C) cooler in tree-
shaded neighborhoods than in treeless areas.
A well-planned landscape can reduce an un-shaded home's
summer air conditioning costs by 15% to 50%. One Pennsylvania study reported air-conditioning savings of as much as 75% for small mobile
homes.
Winter
You may be familiar with wind chill. If the outside
temperature is 10degrees F (-12 degrees C) and the wind speed is 20 miles per
hour (32kilometers per hour), the wind chill is -24 degrees F (-31
degrees C). Trees, fences, or geographical features can be used as
windbreaks to shield your house from the wind.
A study in South Dakota found that windbreaks to the north,
west, and east of houses cut fuel consumption by an average of 40%.
Houses with windbreaks placed only on the windward side (the side
from which the wind is coming) averaged 25% less fuel consumption than
similar but unprotected homes. If you live in a windy climate, your
well planned landscape can reduce your winter heating bills by approximately one-third.
Landscaping for a Cleaner Environment
Widespread tree planting and climate-appropriate landscaping
offer substantial environmental benefits. Trees and vegetation
control erosion, protect water supplies, provide food, create
habitat for wildlife, and clean the air by absorbing carbon dioxide and
releasing oxygen.
The National Academy of Sciences (NAS) estimates that urban
America has 100 million potential tree spaces (i.e., spaces where
trees could be planted). NAS further estimates that filling these spaces
with trees and lightening the color of dark, urban surfaces would result in
annual energy savings of 50 billion kilowatt-hours—25% of the 200
billion kilowatt-hours consumed every year by air conditioners in
the United States. This would reduce electric power plant emissions of
carbon dioxide by 35 million tons (32 million metric tons) annually
and save users of utility-supplied electricity $3.5 billion each year
(assuming an average of $0.07 per kilowatt-hour).
Also, some species of trees, bushes, and grasses require
less water than others. Some species are naturally more resistant to
pests, so they require less pesticides. Another alternative to
pesticides is integrated pest management, an emerging field that uses
least-toxic pest control strategies. One example is to introduce certain
insects such as praying mantises or ladybugs to feed on—and limit
populations of—landscape-consuming pests.
Certain grasses, such as buffalo grass and fescue, only grow
to a certain height—roughly 6 inches (15 centimeters) and are
water thrifty. By using these species, you can eliminate the fuel,
water, and time consumption associated with lawn mowing, watering, and trimming. Also, recent studies have found that
gasoline-powered mowers, edge trimmers, and leaf blowers contribute to air
pollution.
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