A word about efficiency....
There
has always been some confusion about how much
light you get from the different types of light bulb
and how much energy they consume. The new breed of compact
fluorescent (or ‘low energy’) lamps will only use around
11 watts of power to generate the same light as a normal
60 watt light bulb and they last up to eight times longer.
There is no doubt at all that they save you money over
the life of the lamp. A halogen bulb uses about half
the energy of a conventional light bulb to generate
the same amount of light.
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Lightbulb Types. |
Fluorescent light sources
(contain gases in a tube but have no filament)
 These
have been around for many years and are better known
as the long white tubes commonly seen in utility ceilings.
Recent technology has reduced the size and improved
the efficiency. Many different shapes and power options
are available. The benefits are low power consumption
(around 20% of a conventional light bulb) and long life
(up to 8000 hours). They are ideal for lights which
need to be kept on for a long time. Many people assume
fluorescent light is ‘cold’ but ‘warm white’ lamps are
available which improve the colour.
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Incandescent light sources
(conventional filament bulbs)
 These
are the conventional bulbs which we all recognise and
their chief advantage is the colour of light they emit.
Colours of objects are generally more accurate with
this type of light bulb and they impart a warm feeling
to a room. The disadvantage is that they are inefficient
by modern standards and have a relatively short life
(around 1000 hours). Incandescent lamps come in a variety
of shapes and sizes and have a number of different fittings:
Bayonet cap (BC), Small Bayonet cap (SBC), Edison screw
(ES or E27) and Small Edison Screw (SES or E14). The
Edison screw types are becoming more popular in the
UK. Several different coatings are also available with
the following properties: Pearl is an all over frosting
which diffuses the light and is best used in a light
fitting with shades. Clear bulbs are more attractive
when used in fittings where the bulb is visible or a
sparkle is required such as crystal chandeliers
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Halogen light sources
(filament bulbs containing halogen gas)
 Halogen
bulbs produce a very attractive light which closely
resembles sunlight. They are more efficient than incandescent
bulbs using only half the energy to produce the same
light output and last twice as long.
Generally they are small lamps which generate a lot
of heat so they can only be used in light fittings designed
to cope with the higher temperatures. There are two
main types of halogen lamp available in the domestic
market:
Low voltage. These lamps operate on 12V which means
a transformer has to be fitted either in the light fitting
itself or remotely. The advantages of the lower power
are that the safer voltage enables manufacturers to
produce interesting and slim designs without the need
to protect against danger from higher voltages. Transformers
can be either electronic or ‘wire wound’. The newer
electronic transformers are more energy efficient and
smaller but more expensive than the conventional wire
wound type. Electronic transformers can be damaged by
voltage ‘spikes’ in the mains supply (sometimes referred
to as ‘dirty mains’). These spikes can be caused by
fluorescent lights, older motors, fridges, lift shaft
motors etc. If persistent problems occur the use of
mains voltage lighting is recommended.
Mains voltage. This relatively new breed of lamps offers
the light colour advantage of halogen without the need
to house a transformer. The reflector type bulbs are
known as GU10 or GZ10 and the latest small envelope
non-reflector halogens are known as G9.
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Dimmers
Most tungsten
and halogen light fixtures are dimmable but only certain
types of fluorescent can be dimmed. When installing
a dimmer you should check on the compatibility of the
fitting with the dimming device and that the dimmer
has sufficient capacity to control the load on the circuit.
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