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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 tmes 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.
A recent breakthrough in technology
has resulted in the appearance of very bright LED lights.
These are very small but relatively bright for their
size and have a life often in excess of 50,000 hours.
They are yet to appear in any number
in domestic lighting but it is only a matter of time.
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Low Energy and Fluorescent Bulbs (contain
gases in a tube but have no filament). 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.
There is no doubt at all that they can
save you up to 80% on your electricity bill over the
life of the lamp, which can last for up to 5 years (10,000
hours). Naturally, if you are using less electricity,
you need to generate less electricity and this reduces
greenhouse gases, which thin the ozone layer around the
earth.
Fluorescent lamps have no filament;
they are just a tube with gases in it. Best known as
the long white tubes so beloved in utility ceilings of
the 1960's and 70's, recent technology has reduced the
size and improved the efficiency. Many different shapes
and power options are now available.
These lamps are ideal for lights that
need to be kept on for a long time i.e. overnight on
landings or in hallways. In the past it was felt that
fluorescent light was 'cold' but with the invention of
'warm white' lamps this is no longer the case.
Incandescent light sources (conventional
filament bulbs).
These are the conventional bulbs that
we all recognize 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 that 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.
Reflector bulbs have
a silvered surface to direct the light in a certain direction
and are usually intended for directional fittings such
as spotlights.
Halogen light sources (filament bulbs
containing halogen gas)
Halogen bulbs produce a very attractive
light, closely resembling 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 that
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.
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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Many people spend a great deal of money
decorating and furnishing their homes to create an atmosphere
only to find that something is missing. Good lighting
will complement and complete the effect you are seeking
but remember that bright lighting is not always good
lighting.
A light source creates a pool of light
but there is a second effect produced when this light
is reflected by surfaces. It is this secondary effect
that cannot be reproduced in the shop where you buy your
lights. Consider where you are to put the light and the
surfaces under and around it. What effect will the reflected
light have?
Avoid hard contrasts that can be tiring
to the eyes and, where possible, try to combine different
types of lighting in the same room. Direct lighting for
reading or working, pools of light to highlight features
such as paintings or objects and washes of light on walls
all help to add atmosphere to a room whilst remaining
functional. If a room has to perform several functions,
consider installing a dimmer. This will allow a higher
light level for working or reading and a lower light
level for relaxation. This can prove useful too for older
eyes, which need more light.
Colour is most important, incandescent
bulbs help create a cosy atmosphere in living areas while
fluorescent lamps give a cooler, more efficient light
for utility rooms. A room painted in a dark colour will
need more light, as much of it will be absorbed, whilst
lighter colours reflect light. You can add colour to
a room by illuminating a coloured surface.
Avoid glare by placing the lights at
a height that prevents the eye from seeing the bulb directly.
Pendants should not be hung so high that the bulb is
clearly visible underneath. Take care that lights placed
over reflective surfaces such as glass tables have a
diffuser in them.
How much light?
Determining the correct light levels
for a home environment is a very complicated subject
and depends on a degree on the individuals’ perception
and requirements. The formula below, however, can be
used as a rule of thumb.
Measure the room size in square metres
and multiply this by 25 (for incandescent lamps) 15 (for
halogen lamps) or 19 (if using compact fluorescent lamps).
This will give you the total watts required to light
the room.
Example 1: a room 5m
x 5m has an area of 25sq metres. If we are to use conventional
incandescent lamps we multiply this by 25 giving a total
wattage of 625 watts. This can be made up as required,
for example as follows:
2x 75W table lamps =150W
2x 3 light ceiling lights each with 40W bulbs =240W
2x double wall lights each with 40W bulbs =160W
2x single wall lights each with 40W bulbs = 80W
TOTAL =630W
Example 2: a kitchen
3m x 6m has an area of 18 square metres. If we intend
to use low voltage halogen dichroic lamps then we multiply
this by 15 to arrive at 270 watts required in total.
This can be made up as follows:
1x 3 light halogen bar fitting with
adjustable heads each with 50W lamps =150W
6x downlighters mounted in the ceiling each with 20W
dichroic lamps =120W
TOTAL =270W
Please note that this formula is a guide
only and some people prefer more light while others prefer
less. A useful measure is to over estimate by 10-15%
and install a dimmer to give you more control. If in
doubt seek professional advice.
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Avoid using one central light that will
create hard shadows and possibly glare. Instead aim to
use plenty of different light sources to create pools
of light, this will give a more interesting effect.
Let’s start with where you sit.
An adjustable reading light beside or behind your chair
that can be switched whilst seated will prove invaluable.
If it can be adjusted for height it will be even better.
Two or three table lamps placed around the perimeter
on tables, shelves or furniture will give the room a
more spacious feeling as the light radiates inwards.
These small pools of light also create interest.
Illuminate bookcases, pictures or objects
of interest with picture lights or halogen spotlights.
This indirect lighting of a different colour will add
contrast.
Wall lights and pendants on a dimmer
switch can raise the level of illumination in the room
without needing to adjust any of the other light sources
but beware of glare if they are mounted too high. Indirect
light from wall washers (light fittings designed to light
the wall and ceiling often made in ceramic or plaster)
will create dramatic effects. Remember that the light
given from wall washers will be coloured by the surfaces
on which they are mounted.
Floor lamps come in many guises and
can be very effective at adding general illumination
to a dark area where it is not easy to fit wall lights,
ceiling lights or table lamps. A floor uplighter gives
a bright wash on the ceiling. Some are fitted with dimmers
and others have a second flexible arm for reading.
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The
main light source here will be over the dining table.
The use of a dimmer will allow the table to be used
for jobs such as sewing and yet give a low mood light
for dining.
Don’t hang a pendant so
low that your diners have to peer round it; about 60cm
above the table is about right. Better still fit a rise
and fall pendant.
If you like to dine by candlelight,
make sure the heat and smoke is far enough away from
the light fitting.
If you have a glass dining table,
make sure the light is fitted with a diffuser so that
your diners are not looking at a reflection of the light
bulb.
Long tables can be very effectively
lit with a longer light fitting suspended on two wires.
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Great care needs to be taken when choosing
bathroom lighting as the regulations are strict concerning
the type of light you can use.
The bathroom mirror deserves some special
attention and a diffused glass light either side will
give a good general illumination where it is needed.
The alternative is a halogen downlight from the ceiling
or fluorescent strip light over the mirror.
The latest generation of mirrors incorporate
lights, into the mirrors themselves with sections of
the reflective surface removed and lights fitted behind
them. This is a very effective way of generating an even
light and improving safety.
For general illumination in the rest
of the bathroom either use downlights for their refreshing
halogen colour or a high output flush ceiling fitting
to suit the décor.
Portable lights are not permitted in
a bathroom so for mood lighting use ceiling mounted directional
spotlights aimed away from the bath and at interesting
features. Lights designed specifically for showers are
available and must be carefully fitted according to the
instructions,
The following information is a guide
to help you understand what fittings can be placed where.
This is not an installation guide and reference should
be made to the IEE Wirings Regulations (16th Edition)
or a qualified electrician.
Firstly it is important to understand
the rating by which bathroom and some outdoor lights
are classified. IP rating stands for ‘Ingress Protection’ and
is always followed by two characters. These two numbers
refer to level of protection and it is important that
you choose fittings with the correct rating according
to where they are to be sited within the bathroom. The
diagram below shows a bathroom split into four clear
zones: 0, 1, 2 and 3.
Zone 0 is inside the bath or shower
itself. Any fitting used in this zone must be low voltage,
(max 12V) and be rated at least IP67, which is total
immersion proof.
Zone 1 is the area above the bath to
a height of 2.25m from the floor. In this zone a minimum
rating of IP44 is required. If the fitting is 240V a
30ma residual current device (RCD) must also be used
to protect the circuit in this zone.
Zone 2 is an area stretching 0.6m outside
the perimeter of the bath and to a height of 2.25m from
the floor. In this zone an IP rating of at least IP44
is required.
In addition it is good practice to consider
the area around a wash basin, within a 60cm radius of
any tap to be considered as zone 2.
Zone 3 is anywhere outside zones 0,1
and 2 (subject to specific limits) and where no water
jet is likely to be used. No IP rating is required.
In addition to the above, if there is
a likelihood of water jets being used for cleaning purposes
in zones 1, 2 and 3 a fitting rated a minimum IP65 must
be used.
 
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We spend most of our time in the kitchen
and it is a room in which many functions are carried
out.
Safety is paramount where hot liquids,
hot surfaces and electrical machinery are being used
so the kitchen requires a higher level of light than
any other room in the house.
A more even distribution of light is
required in the kitchen and a central light or multi-head
bar with halogen lights will be instrumental in achieving
this. An alternative is the use of halogen downlighters
mounted in the ceiling.
Use lights specifically designed to
be fitted under cupboard units to illuminate work surfaces.
It is important that these lights run cool particularly
where food is being stored on in the cupboard above.
Typically, under cupboard lights are of the fluorescent
type. Above all make sure the light falls on the work
surface and avoid working in your own shadow. If you
have glass fronted cabinets consider the use of small
halogen display lights to add interest.
If the kitchen is also used for dining
it will improve the atmosphere if any fluorescent lights
can be switched off leaving a lower level of halogen
lighting.
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This is an area so often neglected.
Consider the number of functions required of a bedroom.
For dressing you may need a general
illumination or, if your partner has to rise at a different
time, do you need a lower level pool of light that won’t
disturb them? A well-positioned downlighter will help
here.
Many people read in bed and with a double
room, it is useful to have bedside lights that are individually
switched. Adjustable reading lamps are ideal if you want
to read while
your partner sleeps. For convenience and safety you should
aim to have all of the bedroom lights controlled from
the bed.
Dressing tables used for make-up will
need more specific lighting and the use of two slender
table lamps either side of a mirror gives a good working
light without glare and will add to the cosy effect of
the room. Try to create pools of light to reduce any
hard contrasts. Adding a table lamp or illuminating pictures
will be very effective.
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A general background illumination is
important to avoid the hard contrast if only a desk lamp
is used. Indirect wall washers or a floor lamp will do
nicely.
For the desk lamp; look for one which
is adjustable for height and will reach over the area
where you are working. It is most important to avoid
working in shadows.
If you have a computer try and light
the wall behind it to avoid tiring your eyes when looking
at the screen. Make sure the lights in the room do not
reflect off the screen into your eyes.
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A good central ceiling light is useful
to provide a general illumination and a bedside or wall
mounted reading lamp is recommended.
Night lights for children’s rooms
give peace of mind and cost very little to run.
Older children will want to have fun
lighting and there are many effective novelty lights
but always be safety conscious and choose lights which
are suitable for the age of the child.
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