ask ken | energy-saving q&as
Trees Make a House a Home
By KEN SHEINKOPF
QWe moved into a new development a couple of years ago, and while we love our home, the barren yard really looks terrible. We haven’t
been able to afford putting in all the landscaping we’d
like, but we want to start. our biggest problem is keep-
ing heat out of the house, so where should we begin?
—J.L., Hilton Head, S.C.
Ken Sheinkopf has been
working in renewable
energy for 25 years
and knows where to
find the answers to
Got questions about
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in this column.
AI recently told some students about Johnny Apple- seed, the legendary guy who traveled around the country planting apple trees. You may not realize
that he was a real person. John Chapman spent the first
half of the 19th century planting apple trees across the
Midwest, and I think that qualifies him as a true energy
pioneer. That’s because trees do a terrific job of cutting
down on heat and improving air quality, especially in the
heat islands that are a problem in large urban areas.
Heat from the sun gets trapped by buildings, pavement,
asphalt and other dark areas that absorb sunlight rather
than reflect it. Regardless of the temperature the weatherman gives you, areas around buildings can be around 6° to
8°F ( 3° to 4°C) hotter. Without shade from trees, you end
up running more air conditioning to cool your home. Higher temperatures inside and out are uncomfortable and can
lead to health problems like heat exhaustion and asthma.
A study in New Jersey a few years ago found temperatures in Newark, for example, were higher, by up to 11°F
( 6°C), than in the city’s suburbs. While the problem of
heat islands is usually worse in big cities, it’s a factor in
most urban settings.
This is where we get back to Mr. Appleseed. Planting
trees is a great way to provide shade on the roof and walls
of your home, which helps keep temperatures lower. If you
start planting trees in your yard now, you’ll notice increasing
benefit from the shade as the trees grow bigger every year.
Remember what you learned about evapotranspiration back
in school: Trees give off water droplets that draw heat as
they evaporate, and this helps keep the area around them
cooler. In fact, research has found that a properly watered
tree reaching a crown of 30 feet can actually give off as much
as 40 gallons of water every day. A tree giving off that much
water disperses heat equivalent to the amount produced by
a small electric space heater running for four hours.
Trees are also great at absorbing carbon dioxide and filtering pollutants from the air. They absorb sound, prevent
erosion and provide habitat for birds and small animals.
Trees can block strong winter winds and help channel summer breezes into the home.
Once you get trees planted, there are a variety of
bushes, shrubs and ground cover that can improve the
appearance of your home while providing shade and wind
protection. I think it’s important to use native plants and
grasses to minimize maintenance and watering, a tech-
nique called xeriscaping.
A good web site on heat islands ( eetd.lbl.gov/heatisland)
tells more about the benefits of trees in improving the com-
fort level in your home.
QWe like to read your column, but many of the things you write about apply to homeowners, not to renters like us. Sure, some of the tips will
work, but I’d like to read something aimed at the way
renters can save energy. — B.Z., New Hartford, N. Y.
AMost of the basic energy conservation measures I write about apply to renters as well as to homeown- ers. Here are some general tips for anyone, regardless
of where they live, that can help lower your energy use.
regularly to keep the systems working properly and help
keep the indoor air clean.
windows if they’re not shutting tightly.
• Keep the thermostat at 78°F ( 25°C) in summer
and 68°F ( 20°C) in winter. Every degree you raise that
setting higher in summer or lower in winter can save from 2
to 10 percent on heating and cooling costs, so it can make
a big difference.
leave a room. Unplug unused appliances.
faucets and showerheads occasionally to minimize water
use and to reduce the energy used to heat it.
at 0°F (- 18°C). Use a thermometer to verify that the settings
are correct. A full refrigerator keeps the cold in longer when
doors are opened, so fill jugs with water if there isn’t enough
food to keep the unit full. Clean the coils on the back.
days to keep the heat out. Open them during winter days
to allow the sun’s warmth to get indoors.
save the energy used to heat water, and the clothes should
get just as clean.
is adequate for most home needs. GS