Lighting for Energy Efficiency
Lighting includes both electric lighting and natural lighting
from the sun, or day lighting. Although day lighting in homes is
not a large source of energy savings, it can dramatically
increase the comfort and livability of the home. Where
day lighting isn't practical, you should consider installing
energy-saving compact fluorescent bulbs and other
energy-efficient lighting fixtures and controls.
Homes that incorporate these features not only use less
electricity, but also stay cooler in the summer because less
heat is being generated by lights. Light bulbs also create
uneven heat loads in your home, which makes constant and even
temperature control harder to achieve.
Day lighting
Effective
day lighting is
difficult to achieve as a retrofit to an
existing house. Although skylights are an
obvious approach, they often cause overheating
in the summer and heat loss in the winter.
Triangular "roof monitors," with vertical
glazing, are a more energy-efficient approach.
You
can also enhance your use of existing daylight
through careful interior design. Bright interior
colors help reflect daylight into the interior
of the house. Desks, reading chairs, and dining
room tables can be strategically located to best
use the available light, but beware of glare
problems if locating a computer in a daylight area
Electric Lighting
Although lighting accounts for only 3.3% of the
energy use in homes, it often accounts for a
large fraction of the electricity bill. You can
cut your electricity use significantly by
installing energy-efficient lights, fixtures,
and controls.
Compact fluorescent light
bulbs can replace the incandescent light bulbs
in most light fixtures in your home, and they
are now widely available. Compact fluorescent
lights use one-fourth the amount of electricity
that incandescent lamps use, and they last seven
times longer. Because they use less electricity,
compact fluorescents also reduce carbon
emissions, which is good for the environment. For a
detailed analysis of the lights in your house to
see which ones should be replaced, see Lawrence
Berkeley National Laboratory's
Energy Advisor.
Torchieres are a fashionable and inexpensive
means of lighting a home, but they are large
energy wasters. Lawrence Berkeley National
Laboratory has developed a torchiere that uses
compact fluorescent light bulbs to significantly
cut energy use. These are now commercially
available.
For
outdoor lighting, consider combining
energy-efficient light bulbs with motion sensors
that only turn on the lights when people are
present. This approach provides convenience and
security while greatly reducing energy use.
When choosing any
kind of lighting fixture, whether indoor or
outdoor, look for the
ENERGY STAR®
label.
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