Energy
Saving Lighting
Lighting is an element of
our home and work environment that affects our life in many different
ways.
Lighting lets us see to carry out the
daily tasks of life; it affects our comfort and mood, and it
can provide safety and security.
Lighting and lighting fixtures also play a major role in the
interior decoration
of our homes.
Our consumption of electricity related
to lighting also affects our budgets, both at home and in our
workplaces. The Department
of Energy reports that we spend, on average, 5-10% of our
electric bills on lighting in our homes. In some regions of the
U.S.
this amount can be as high as 25% where air-conditioning
is a modest
portion of the bill.
The below information can provide ideas on how you can reduce
your home's electric bill by installing energy-efficient
lighting, and
will also provide you with a general overview of home lighting
concepts.
As a point of origin, let's look at some
basic concepts that will help us to better understand how these
savings can be
achieved.
Energy Efficiency with Lighting
Saving lighting energy requires either reducing electricity
consumed by the light bulbs and light fixtures or reducing
the length of
time that the lights are on. This can be accomplished
by:
- Reducing the amount of time that lights
are on. This can be accomplished by using dimmers and other
lighting controls, and educating
family members to turn off unnecessary lights.
- Lowering wattage, which
involves replacing bulbs or entire fixtures with bulbs and
fixtures that provide the same amount
or greater amounts of light but with reduced electricity usage. Today,
this can be accomplished most easily by replacing inefficient
incandescent bulbs with incandescent/halogen bulbs or compact fluorescent
bulbs
Making the appropriate lamp selection
A "lamp" is the term used in the lighting industry
to describe what is most commonly called
a light bulb. The key to
lighting energy savings lies in the choice
of lamp.
There are three primary families of lamps,
or bulbs:
- Incandescent
- Fluorescent
- High Intensity Discharge
Historically incandescent lamps have
been the most frequently used in residential applications due
to their low initial cost. Incandescent sources, however, are relatively
inefficient in their
conversion of electrical energy to visible light and
can, therefore,
add unnecessary
electrical costs to our electric bills. Fluorescent
and High Intensity Discharge lamps have been used most often
in commercial and industrial applications. Their initial
cost is more than incandescent lamps; but they are much more energy-efficient
and last significantly longer.
Due to major improvements over the last
few years in the color rendering abilities of fluorescent
lamps, and the availability
of small fluorescent bulbs called "compact fluorescent lamps" or "CFLs",
fluorescent lamps are now a very viable alternative to incandescent
lamps for home lighting use. As an example, for the same amount
of electrical energy, compact fluorescent bulbs produce 3-4 times
more light than an incandescent bulbs.
Incandescent Options
Incandescent lamps are the least expensive to buy but the
most expensive to operate. Incandescent lamps also have the
shortest
lives of the common lighting types. They are also relatively inefficient
compared with other lighting types.
The three most common types
of incandescent lamps are:
- standard incandescent
- tungsten halogen
- reflector lamps
Standard incandescent
Known as the "A-type light bulb," these lamps are the
most common yet the most inefficient light source available. Note
that a larger wattage lamp or bulb may not be the most energy-
or cost-effective option, depending on how much light is needed. "Long-
life" bulbs, with thicker filaments, are a variation of these
A-type bulbs. Although long-life bulbs last longer than their regular
counterparts, they are less energy efficient. The best option to
achieve energy-efficiency is to replace "A" lamps
with compact fluorescent lamps, which will be discussed
below.
Tungsten
Halogen
This newer type of incandescent lighting achieves better
energy efficiency than the standard A-type bulb.
These lamps are more
expensive than standard incandescents but can have
significant impact on achieving greater light output
than standard incandescent
lamps.
Reflector lamps and Parabolic
Aluminized Reflector lamps
Reflector lamps (Type BR) are designed to spread
light over specific areas and are used mostly in
recessed
downlight
fixtures. Parabolic aluminized reflectors (Type PAR) are an excellent replacement
for the BR lamps. They have a specially designed reflector that
is highly efficient in pushing light into the space.
Fluorescent
Fluorescent lighting is used mainly indoors,
both for general/ambient lighting and task
lighting, and is about 3 to 4 times as efficient
as incandescent lighting. Fluorescent lamps last about 10 times
longer than incandescents. To gain the most efficiency, you should
install fluorescents in places where they will be on for several
hours at a time. You can also increase the energy savings for existing fluorescent
lighting by replacing them with a more efficient model (providing
a lower wattage but approximately the same light output), or by
replacing the existing fixture with a more efficient model.
Compact Fluorescent
Compact fluorescent lamps CFLs) are the most significant
lighting advance developed for homes in recent years. They
combine the efficiency
of fluorescent lighting with the convenience and popularity of
incandescent fixtures. CFLs can replace incandescents that are roughly three to four
times their wattage, saving up to 75% of the initial lighting energy.
Although CFLs cost from 10 to 15 times more than comparable incandescent
bulbs, they also last 10 to 15 times as long. This energy savings
and superior longevity make compact fluorescent lamps an excellent
choice for residential use.
As previously discussed, CFLs are one of the best energy efficiency
investments available. When introduced in the early- to mid-1980s,
CFLs were bulky, heavy, and too big for many incandescent fixtures.
However, newer models with lighter electronic ballasts are only
slightly larger than the incandescent lamps they replace. The new
CFLs also produce a better color for the home.
CFLs come in integral and modular designs. Integral CFLs have
a ballast and a lamp in a single disposable unit. Modular designs
feature a separate ballast that serves about five lamp replacements
before it wears out.
High-Intensity Discharge
High-intensity discharge (HID) lamps provide the highest effectiveness
and longest service life of any lighting type. They are commonly
used for outdoor and street lighting, but have very limited applications
in homes. Their residential use is limited to outdoor lighting
for driveways, backyards, etc.
Replacing Lamps and Fixtures
"
Relamping" means substituting one light bulb for another to
save energy. You can decide to make illumination higher or lower
when relamping. But be sure that the new bulb's light output fits
the tasks performed in the space and conforms to the fixture's
specifications. Matching replacement bulbs to existing fixtures and ballasts can
be challenging, especially with older fixtures. Buying new fixtures
made for new lamps produces superior energy savings, reliability,
and longevity compared with relamping.
Energy-Efficiency with Lighting Controls
Lighting controls are devices for turning lights on and off or
for dimming them. The most useful controls for increasing lighting
energy-efficiency in a home are dimmers, photocells, and occupancy
sensors.
- Dimmers reduce the wattage and output of incandescent and fluorescent
lamps and significantly increase the service life of incandescent
lamps. Dimming fluorescents requires special dimming ballasts and
fixtures, but does not reduce their efficiency.
- Photocells turn lights on and off in response to natural
light levels. Photocells switch outdoor lights on at dusk and
off at
dawn, for example.
- Occupancy sensors activate lights when a person
is in the area and then turn off the lights after the person
has left. They
are popular for areas such as closets and recreation rooms.
Energy-Efficiency with Ceiling Fans
Although ceiling fans cannot contribute directly to savings
on lighting energy costs, they can contribute significantly
to
savings on electrical costs associated with space heating and cooling.
Household electrical costs associated with space heating
and cooling are in the range of 35-45%. Using a ceiling
fan can help to cool
our homes in summer, and helps to distribute heated air
in winter more efficiently. Although it's difficult to identify an exact savings amount related
to the use of ceiling fans, it's an established fact that ceiling
fans can help to reduce electrical costs by creating greater efficiency
in how we heat and cool our home environments. Especially in summer,
it's often more comfortable to turn off the air-conditioner at
night, and use a ceiling fan at low speed in the bedroom.
To educate your family members on the importance
of energy conservation, appoint a Household Energy Monitor to turn
off lights, set the
thermostat, and keep the windows/doors closed if the air conditioning
or heater is on. Rotate the position so that all family members
share in the responsibility. For the energy and money your family
saves, have a family outing to celebrate your family's is contribution
to energy conservation.
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