| Light
bulbs and tubes Bulbs and tubes can be grouped in
general categories according to how they produce light. The
following is a brief breakdown.
INCANDESCENT BULBS. A tungsten filament burning inside a glass
bulb filled with inert gas, usually argon, produces the warm
incandescent light that we’re all familiar with. The
most common incandescent bulb is the pear-shaped A-bulb, but
not many other shapes and sizes are available. Most incandescents
are designed for standard 120-volt household current, but
low-voltage versions are also available.
INCANDESCENT BULBS.
A tungsten filament burning inside a glass bulb filled with
inert gas, usually argon, produces the warm incandescent light
that we’re all familiar with. The most common incandescent
bulb is the pear-shaped A-bulb, but not many other shapes
and sizes are available. Most incandescents are designed for
standard 120-volt household current, but low-voltage versions
are also available.
Incandescent bulbs have excellent color rendering properties
but, in general, are not very efficient. While A- bulbs are
inexpensive to buy, they don’t last nearly as long as
other bulb types. Use a more efficient source (such as fluorescent
light) when the warmth and excellent color-rendering properties
of incandescent light are not crucial.
FLUORESCENT TUBES.
 When electricity passes through a fluorescent tube, it burns
the mercury vapor there, producing ultraviolet light that
is radiated as visible light by the phosphors coating the
inside of the tube. Because the light comes evenly from the
entire tube surface, it spreads in all directions, creating
a steady, shadow less light. Tubes require a ballast to ignite
and maintain the electrical flow. You can also get energy-saving
compact fluorescents that screw into a socket; these can be
used to replace incandescent bulbs in regular fixtures.
Fluorescent tubes are unrivaled for energy efficiency, and
they last far longer than incandescent bulbs. In some energy-conscious
places, ambient lighting in kitchens and bathrooms must be
fluorescent.
Other fluorescent tubes have been criticized for noise,
flicker, and poor color rendition. Electronic ballasts and
better fixture shielding against glare have remedied the first
two problems; as for color, manufacturers have developed fluorescents
in a wide spectrum of hues, from very warm (about 2,700 degrees
K) to very cool (about 6,300 degrees K).
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HALOGEN BULBS.
 Containing a tiny quartz filament and a chemical coating
(halogens), these bulbs produce a brighter beam and last longer
than incandescent sources. They’re excellent for task
lighting, pinpoint accenting, and other dramatic effects.
Many halogen fixtures use tube-shaped halogen bulbs, but there
are a variety of shapes on the market including bulbs shaped
to replace common incandescent A-bulbs, and various reflectors.
Halogen is usually low-voltage but may be standard 120-volt
household current.
Halogen’s one disadvantage, besides the initial cost,
is that it’s very hot. To be used safely, halogen bulbs must be used in halogen fixtures. Shop carefully; some fixtures
on the market are not UL-approved.
OTHER SOURCES.
High-intensity discharge (HID) bulbs produce light when electricity
excites specific gases in pressurized bulbs. Requiring special
fixtures and ballasts, these lights may take several minutes
to ignite after being switched on. The color emitted by most
HID bulbs is rather unflattering, but they offer long life
and efficiency. One HID source-mercury vapor - is commonly
used for outdoor security lighting.
 Neon light is also generated by electricity passing through
a gas; neon gas glows orange-red, while other gases give off
a variety of colors. Neon is almost strictly decorative. Cold
cathode, a close cousin of neon, puts out more light and is
useful for ambient or indirect lighting as well as decoration.
Fiber optics allow for exciting installations but at present
are quite pricey.
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Light
fixtures
Once you’ve
formed some ideas about the kinds of light sources you
need, selecting fixtures would appear to be easy. But
given the great variety available today, finding the
right fixtures can be confusing and downright complicated.
Here are some points to keep in mind.
FIXTURE TYPES.
Your basic fixture options include movable lamps, surface-mounted
ceiling and wall lights, track systems, and recessed
downlights.
In addition, built-in coves, cornices,
valances, and soffits can be used when indirect lighting
is desired. Architectural in design, these devices shield
light sources from view, allowing light to spill out
around the shield. You’ll find these built-in
fixtures in action throughout the following section,
“Great Lighting Ideas.”
BEAM PATTERN.
One of the primary considerations for any fixture is
how it directs light. Does it create a narrow, focused
beam of light, a broad, diffuse spread- or something
between? For greatest efficiency, match the fixture’s
light distribution pattern to the lighting need.
SIZE.
Fixtures often seem smaller in the store than they will
in your home. Take measurements of your top choices;
then hold bowls or boxes of the same sizes in place
at home to evaluate the scale. Manufacturers often produce
fixtures in graded sizes, so ask about other possibilities.
  
DESIGN.
Personal taste will be your guide, leading you to whatever
suits your décor. Professionals have found that
a sense of decorative continuity can be created by using
similar fixtures throughout a home. In response, manufacturers
offer “families” of fixtures that include
spotlights, pendants, track lights, and ceiling fixtures.
COST.
When calculating costs, there’s more to consider
than the price of the fixture. The energy consumption
of the bulbs or tubes that will be used in the fixture
is a significant factor. Also, be aware that some fixtures
are more efficient than others, transmitting a higher
percentage of the light produced by the bulbs or tubes
they contain and, therefore, providing more light for
the amount of electricity consumed.
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BUILT-IN COVE LIGHTING |
TRACK
RECESSED DOWNLIGHT |
| COST.
When calculating costs, there’s more to consider
than the price of the fixture. The energy consumption
of the bulbs or tubes that will be used in the fixture
is a significant factor. Also, be aware that some fixtures
are more efficient than others, transmitting a higher
percentage of the light produced by the bulbs or tubes
they contain and, therefore, providing more light for
the amount of electricity consumed.
FLEXIBILITY.
Tastes, habits, and styles change over the years. Your
lighting system should be flexible enough to accommodate
such changes. Movable or adjustable lamps, of course,
are flexible by design. But track systems and even recessed
downlights can be changed, too. You can move fixtures
along a track or readjust the way they’re aimed.
A regular built-in downlight can be transformed into
an accent light or a wall-washing light.
MAINTENANCE.
To operate efficiently, all fixtures need to be cleaned
regularly. Kitchens, bathrooms, and work areas in particular
demand fixtures that are easy to reach and clean. For
hard-to-reach areas, such as above stairs, a fixture
with a long-lived fluorescent of halogen bulb is a good
choice.
| WHAT ABOUT LOW-VOLTAGE? |
Low-voltage lighting for indoor
use has become common on the residential scene.
Operating on 12 or 24 volts, low-voltage lights
require transformers (sometimes built into the fixture)
to step down the voltage from standard 120-volt
household circuits. The small bulbs are especially
useful for accent lighting, where light must be
baffled or precisely directed onto a small area.
The compact fixtures that house the bulbs are decorative
in their own right.
Low-voltage fixtures and bulbs are relatively expensive
to buy, but this kind of lighting can be energy-efficient
if carefully planned. |
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