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SILICON CHIP is published 12 times
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ISSN 1030-2662
2
SILICON CHIP
Low voltage lighting is not low wattage
It is interesting to see the trends in lighting in new houses these days. On
the one hand there is a move to energy saving fluorescent lamps; not the
strip lamp style which is well and truly out of favour with interior designers
but the new compact types which plug into the standard bayonet lamp
fitting. These are certainly more efficient than conventional incandescent
lamps but are a great deal more expensive than standard fluorescent tubes.
On the other hand , there is the trend to low voltage halogen spot lights.
The small halogen lamp reflectors which are recessed into a cBiling are
almost invisible when not turned on and they provide a brilliant white light
which is great for highlighting decorative items such as glassware or
sculpture. As far as interior decorators and architects are concerned, these
lamps are definitely "in".
The problem with these lamps is that the general public think that
because they are low voltage, they must be low wattage and therefore don't
cost much to run. And so it is not unusual to walk into a modern show home
and find a dozen or more of these jewel-like spot lamps used in one room.
They are not being used as highlights but for general illumination. Hence,
you might find a "designer" kitchen with all the lighting provided by these
spotlights. The general effect is one of gloom pierced by a few brightly lit
areas.
Typically, these lamps run at 12V and consume 50 watts each. So you can
have a kitchen or family room with 500 watts or more of lighting and still
not have a brightly lit room. When you consider that each of these expensive fittings is also backed by a transformer, then the actual power input is
even higher. Another thing to consider is that because they are halogen
lamps , those tiny bulbs become intensely hot; that is why they are intensely
bright. I;3ut that intense heat also rapidly discolours their tiny reflectors and
so the brightness drops off rapidly - while you continue to pay for all that
power.
Even sillier, some people want their low voltage lighting to be dimmable.
Ordinary incandescent lamps can be dimmed but attempting to dim halogen lamps makes them very inefficient indeed.
The whole point of this is that if you like the look of low voltage halogen
spot lights in your home, then go ahead and install them. But realise that
they are not effective for general lighting and they are not efficient - you
will pay much more than if you had used fluorescents.
Leo Simpson
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