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. 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 reduce overall energy bills.
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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