CE61 Energy efficient lighting – guidance for installers and specifiers

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CE61
Energy efficient lighting –
guidance for installers
and specifiers
Contents
1 Introduction
1.1
Reducing demand
1.2
Potential savings
3
3
3
2 Light sources
2.1
Performance characteristics
2.2
Incandescent tungsten filament lamps
2.3
Tungsten halogen lamps
2.4
Tubular fluorescent lamps
2.5
Compact fluorescent lamps (CFLs)
2.6
High pressure sodium (SON) lamps
2.7
Metal halide lamps
4
4
5
5
6
6
9
9
3 Control gear
3.1
High frequency (HF) electronic control gear
10
10
4 Luminaires for CFLs
11
5 Standards for energy efficient lighting
5.1
Building regulations requirements
5.2
Energy Saving Trust standards
12
12
13
6 Opportunities for energy efficient lighting
6.1
Lighting design
6.2
Lighting control
14
14
15
7 Dimming
7.1
Dimmers for incandescent lamps
7.2
Fluorescent lamps
18
18
18
8 Glossary
19
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
1 Introduction
Home energy use is responsible for 27 per cent of UK
carbon dioxide (CO2) emissions, which contribute to
climate change. Increased insulation levels, especially in
new homes, have driven down the energy needed for
heating. This means that electricity for lighting is a growing
proportion of energy used in the home. The high cost of
electricity – and the emissions associated with it – makes
lighting a prime candidate for action to improve energy
efficiency. By following the Energy Saving Trust’s best
practice standards, new build and refurbished housing will
be more energy efficient – reducing these emissions and
saving energy, money and the environment.
The fourth item on the list can really only be satisfactorily
addressed during the initial design and construction of the
dwelling, or in the course of major improvements; while the
fifth is a combination of direct advice and careful thought, for
example, placing controls where occupants are more likely to
use them.
Technical terms underlined in this guide are explained
in the glossary on page 19.
There are important environmental benefits too. Most UK
electricity is generated by power stations using fossil fuels,
which releases large amounts of CO2 into the atmosphere. The
potential emissions savings over 10 years is equivalent to nearly
5,300,000 tonnes of CO2 – the same as one year’s emissions
from nearly 900,000 houses.
1.2Potential savings
On the basis that dwellings are rewired on an average cycle of
40 years, the total number of homes undergoing major electrical
work in any year (including installation in new properties) is
around 790,000 (or 2.5 per cent of the housing stock). If, in each
of these, half the rooms were fitted with energy efficient lighting,
Designers, builders and electrical installation contractors the electricity savings would be equivalent to nearly 230 million
all have a role in ensuring that lighting is as energy
kilowatt hours (kWh) in the first year. This would mean reductions
efficient as possible through the specifications they use in energy bills of over £18 million.
and the advice they give to clients.
Yet these savings are not ‘one offs’ – they continue to
This guide focuses on:
accumulate. And each year more houses would be made more
• Options for greater energy efficiency of lighting in
energy efficient, adding to the total number. The cumulative
the home.
impact on energy consumption over a 10 year period can be
• Opportunities to improve lighting design.
seen in Figure 1. In fact, by the end of this time, a total of over
• Savings that are available with different lighting
12,500 million kWh (45 petajoules (PJ)) would have been saved,
technologies.
worth some £990 million at 2006 prices.
Most of the technologies and approaches outlined
in this guide apply to all types of residential
accommodation including houses, hostels, care homes
and student accommodation. However, it should be
noted that these latter categories may be considered as
‘non-domestic’ for the purposes of building regulations,
and additional specific regulations may apply.
Cost saving
(£m)
Energy savings
(Petajoules)
1200
50
1.1Reducing demand
Energy demand for lighting can be reduced by:
• Using energy efficient lamps and luminaires
(light fittings).
• Directing light to where it is needed.
• Controlling the use of lighting.
• Making the most of daylight and using reflective
room surfaces.
• Influencing user behaviour.
Immediate results can be made in the first three items
listed through basic home improvement, although
the greatest potential for savings will be realised in
new homes or, for existing buildings, during periodic
refurbishment work such as rewiring.
1000
40
800
30
600
400
20
200
10
0
1
2
3
4
5
Year
6
7
8
9
10
0
Figure 1 Energy and cost savings from increased use of energy efficient lighting.
1PJ is equivalent to 278 million kilowatt hours (kWh).
The National Inspection Council for Electrical Installation Contracting (NICEIC)
recommends inspection every 10 years and on changes of occupancy.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
2 Light sources
Lamp type
10
30
Efficacy
(Lumens per Watt)
50
70
90
110 130 150
2
6
Average Life
(Thousand hours)
10
14
18
22
26
30
Colour
rendering
Colour
temperature
K
Tungsten filament
90-100
Excellent
2800
Tungsten by halogen
90-100
Excellent
3000
40-69
Poor/moderate
3000-4000
80-100
Very good/excellent
2700-6500
80-100
Very good/excellent
2700-6000
20-39
Very Poor
2500
80-100
Very good/excellent
3000-6000
Tubular fluorescent (halophosphate)
Tubular fluorescent
(triphosphor and multi-phosphor)
Compact
fluorescent
High pressure sodium
(SON/E and SON/T)
Metal halide
Figure 2 Performance characteristics for a range of lamp types
Figure 2 compares the performance of the different
types of lamp that are commonly available. Some lamp
types may only be appropriate for communal areas or
multi-residential housing, but they have been included
for completeness.
2.1Performance characteristics
Efficacy
Efficacy is a measure of how effectively a lamp
transforms electricity into light (or luminous flux) in
lumens per Watt. The efficacy ratings in Figure 2 are
based on a lamp’s performance when new. Efficacy
varies, depending on a number of factors including
wattage, operating frequency and type of phosphor
coating, so the results are displayed in bands. However,
it should be noted that the amount of light reaching
the occupant will depend heavily on the direction of the
light and the characteristics of the complete light fitting
(luminaire). Section 4 gives more information on this.
Average life
Lamp life can be measured in different ways, which
can result in misleading comparisons between different
types. The method used for all discharge lamps in
Figure 2 (that is, all types except tungsten filament and
tungsten halogen) is based on rated average lamp life.
This is the time taken for 50 per cent of a sample batch
to fail under test conditions.
As with efficacy, lamp life is shown in bands because it
can vary with operating voltage, wattage and type of
control gear. It can also be affected to a lesser extent
by the operating position. Frequent switching of lamps
can also affect operating life, particularly in the case
of fluorescent lighting (although specialist fluorescent
lamps are now available with are designed to withstand
such use).
Although switching may affect operating life, it is not
true that fluorescent lamps consume large amounts of
energy every time they are switched on – they should
always be turned off when not required.
Colour rendering and colour temperature
Colour rendering is a measure of how accurately the
colour of surfaces appears under different light sources.
It is expressed by a colour rendering index (Ra) of up to
100. An Ra of between 80-89 is considered very good,
while one between 90-100 is regarded as excellent.
In general, an Ra greater than 80 is adequate for all
domestic situations and wherever accurate colour
judgements are necessary.
Colour temperature gives an indication of the
appearance of the light. Lower colour temperatures
mean a ‘warmer’ appearance. Early fluorescent
lamps had a high colour temperature giving a very
‘cold’ appearance; but now a wide range of colour
temperatures is available, including some that are similar
to incandescent lamps. Lamps of different temperatures
should not normally be used in the same room, unless
a specific effect is required.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
2.2Incandescent tungsten filament lamps
These are the most common type of lamp and include general
lighting service (GLS) lamps. Decorative versions are available
(e.g. candle-shaped lamps). ‘Incandescent’ literally means light
produced from heating, and in these lamps the heat is created
by an electric current passing through a thin tungsten wire
(filament). This filament is quite delicate and burns out after
about 1,000 hours. Some ‘double life’ lamps are available but
the gain in working life is made at the expense of light output
(e.g. GLS lamps with a 2,000 hour life have approximately
10 per cent less light output).
These lamps, which are used in most homes, only have an
efficacy of 8-15l/W.
2.3Tungsten halogen lamps
These are tungsten filament lamps that contain a small
quantity of halogen (iodine or bromine). This prevents
blackening of the glass which can lead to loss of light output
over the life of the lamp.
Extra low voltage (ELV) versions are available in 6V, 12V and
24V ratings – with 12V being by far the most popular. Efficacy
is typically 15-20l/W, although new models offer around
28l/W. Life span can be up to five times that of a tungsten
filament lamp. The small filaments provide excellent beam
control when used with precisely contoured integral reflectors.
ELV lamps require transformers, but these are normally small
lightweight electronic units that can be dimmed (although
this requires special phase control dimmers suitable for
inductive loads).
These lamps will save energy when used to replace tungsten
filament lamps, but they cannot be used to comply building
regulations because the regulations require an efficacy of
40 lumens per Watt (see Section 5).
Mains voltage tungsten halogen lamps offer 10-15 per cent
more light and double the working life of tungsten filament
lamps. Modern models are very compact – almost as small
as ELV lamps. They can be easily dimmed with conventional
phase control dimmers designed for resistive loads.
Lamps from reputable manufacturers have integral fuses for
safe end-of-life failure. Poor quality lamps may have inadequate
fuses – or no fuse at all – leading to violent shattering and
permanent damage to any dimmer in the circuit.
Both types of tungsten halogen lamp must only be used in
the appropriate luminaires – for example, mains voltage lamps
must not be used in ELV fittings and vice versa.
Tungsten filament lamps
Advantages
• Low purchase price.
• Excellent colour rendering.
• No control gear required.
• Full lighting level immediately
when switched on.
• Easily dimmed.
• Sparkle lighting effects can be achieved.
• Universal operating position.
Disadvantages
• Low efficacy – only 8-15l/W.
• Short working life – usually about 1,000 hours.
• High running costs.
• Not rated as energy efficient under building regulations.
Tungsten halogen lamps
Advantages
• Higher efficacy than
conventional tungsten
filament lamps.
• Bright, white light.
• Life of 2,000-5,000 hours
depending on model.
• Excellent colour rendering.
• Full lighting level immediately when switched on.
• Dimmable.
• No transformer required for mains voltage models.
Disadvantages
• Transformer required for ELV lamps.
• Very high operating temperature.
• Double-ended types must be used in horizontal position.
• Not rated as energy efficient under building regulations.
Ultraviolet (UV) radiation
Concern has been expressed about ultraviolet radiation from
electric lights. It is true that lamps used for general lighting will
emit some UV. However, this is at a much lower level than would
be experienced just by being outdoors.
Under typical indoor lighting, the UV radiation from bare
fluorescent lamps would be less than 1 per cent of that received
in average daylight (see LIF Technical Statement No.8,
www.lif.co.uk) ten filament lamps hardly emit any UV because the
UV is absorbed by the glass envelope. Most tungsten halogen
lamps are now made with UV-filter quartz and this removes the
need for additional filters in most applications. Further information
is available from lamp manufacturers.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
Tubular fluorescent lamps
Advantages
• Low running costs.
• High efficacy: 55-104l/W.
• Colour rendering is excellent or very good (except
halophosphate).
• Long life in normal use (up to 24,000 hours for a T5 lamp).
• Minimal loss of output during working life.
• Prompt start and re-start (with HF electronic control gear).
• Full light output level achieved quickly.
• Up to 10 per cent energy saving with 10 per cent more
light by replacing a T12 lamp with a T8 lamp in
switch-start luminaires.
• Universal operation position.
• Range of colour temperatures (2700-6500K).
Disadvantages
• Frequent switching shortens life (less pronounced with
HF control gear).
• Control gear is required.
• Dimming requires special control gear and dimmer.
Compact
fluorescent lamps (CFLs)
Advantages
• Low running costs.
• High efficacies: 50-75l/W (some small CFLs may be less
than 40l/W).
• Life: 8,000 to15,000 hours (depending on type).
• Suitable for replacing tungsten filament lamps.
• Very good colour rendering (some lamps give excellent
rendering).
• Range of colour temperatures for pin-base lamps:
2700-4000K.
• Full light output level achieved quickly.
• Prompt start and re-start.
• Four-pin lamps can be dimmed (with specialist control
gear and dimmer).
• Universal operating position.
Disadvantages
• Frequent switching shortens working life (although
specialist lamps are available to address this issue).
• Control gear required (which is built-in on some lamps).
• Not suitable for dimming using standard domestic
dimmer switches (although specialist CFL-dimming
equipment is available).
2.4Tubular fluorescent lamps
These have between four and 10 times the efficacy of tungsten filament
lamps and can last up to 24 times longer, depending on lamp type and
control gear. (All fluorescent lamps need control gear.) Any flicker from
these lamps is due to the control gear, not the lamp itself. It can often
be eliminated by using high frequency (HF) electronic control gear (see
Section 4).
Tubular fluorescent lamps work in a different way from incandescent
lamps. The tube contains an inert gas, usually argon or krypton at
low pressure, together with a small amount of mercury. When an arc
is struck between the tube’s electrodes, the mercury atoms emit UV
radiation. This excites the phosphor coating on the inside of the tube,
which gives off visible light (the coating fluoresces).
The quality of this light depends on the coating used. Older
halophosphates degrade over the life of the lamp resulting in loss of
light output; the newer tri-phosphor and multi-phosphor coatings last
much better with the latest tri-phosphor lamps, maintaining most of
their output throughout their working lives. The tri-phosphor coatings
also achieve very good colour rendering and are available in a range
of colour temperatures – including the warmer 2700K and 3000K
temperatures suitable for domestic use.
Older fluorescent tubes of 600mm or more in length were usually
38mm in diameter (known as T12 lamps). Most new fittings use T8
lamps (26mm in diameter). They will save up to 10 per cent of the
energy consumption while giving 10 per cent more light. T8 lamps are
available in the same lengths and can be used as replacements for
T12 lamps in the same switch-start luminaires.
Newer 16mm diameter T5 lamps have even higher efficacies
(90-104l/W) but need different fittings. (A wide variety are now
available.) Where very discrete light sources are required, specialist
luminaires with 7mm diameter T2 lamps can be used.
2.5Compact fluorescent lamps (CFLs)
CFLs are very energy efficient and are ideal for locations where heavy
use (more than four hours a day) may be expected, or where areas
are likely to be lit continuously: in living areas; in circulation zones
such as halls, stairways, landings and shared passageways outside
buildings. Their low operating temperature makes them particularly
suitable for luminaires where heat build-up should be avoided, such
as flush-wall and ceiling fittings. Their long life makes them attractive
for locations where access to change the lamp could be difficult for
occupants, such as above stairwells, or where residents are less able
(e.g. sheltered accomodation), and enclosed applications such as
bathroom mirror lights.
CFLs fall into two main categories:
• Pin-base lamps.
• Lamps with integral control gear (CFLi).
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
Comparing costs: CFLs and tungsten filament lamps
Figure 3 compares the costs of using an 18W pin-base CFL and 100W GLS tungsten filament lamp over a
12,000 hour operating period. (12,000 hours is a typical CFL lifespan.) The calculations are shown below:
100W GLS
Cost
Life (hours)
Total lamp costs (over 12,000 hours)
Total electricity costs (@ 7.9p per kWh)
Total costs
18W CFL
(plus electronic control gear
consuming 3W*)
£0.50
£3.70
1,000.00
12,000.00
£6.00
£3.70
£94.80
£18.96
£100.80
Saving
£22.66
£78.14
* electronic control gear extends lamp life and allows the CFL to run at a lower wattage (17W assumed) for the same
light output – see section 3.
The additional cost of the dedicated low energy fitting is in the order of £6-12 (excluding installation costs)
compared with one designed to accept an incandescent lamp. As this is a one-off cost not incurred when
replacing lamps, it has not been included in these calculations.
Over 90 per cent of the energy used by incandescent lamps is given out as heat. This means that they contribute
to meeting the heat demand of a building during the heating season. Consequently, changing to energy efficient
lighting will result in an increase in energy used for heating (known as the heat replacement effect). This additional
energy used for heating will partially offset the cost and savings attributed to energy efficient lighting. Savings
from lamps used in unheated areas (external lights, garages, etc.) are not affected.
Cost (£)
110
100
90
80
70
60
50
40
30
20
10
100W GLS
Savings = £78.14
over 12,000 hours
18W CFL
(electronic ballast)
0
Hours of use
12,000
Figure 3 Comparative costs of buying and using CFLs and tungsten filament lamps
CFLi
CFLi may have bayonet or Edison screw caps and
can therefore be used as direct replacements for
incandescent lamps in most existing luminaires.
Almost all CFLi have a colour temperature of 2700K,
the same as that of tungsten filament lamps.
Pin-base
Pin-base lamps need separate control gear and
luminaires specially designed for them (sometimes
referred to as dedicated fittings). They cannot be
replaced with incandescent lamps when they fail,
and so the savings from using high efficiency lamps
continue throughout the life of the luminaire.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
They are available in a wide range of colour
temperatures, including those most commonly
encountered in domestic situations: 2700K – the same
as the tungsten filament lamp; and 3000K – the
same as tungsten halogen lamps. Pin-base lamps can
be used to meet the Energy Saving Trust’s standards
for new housing and can be used to comply with the
building regulations (see section 5).
The manufacturer’s stated wattage for pin-base
lamps does not include the power consumed by
the separate ballast. While dedicated fittings may
take slightly lower wattage lamps, the total energy
consumed will be very similar to CFLi.
General
CFLs with a wattage of about 20 – 25 per cent
that of an incandescent lamp will give a similar light
output. However, the distribution of light from a CFL
may be different (Section 4), and this may influence
the choice of lamp type and its wattage.
Lamps in both categories are available as ‘sticks’ where
the fluorescent tube is visible and ‘look-alikes’ where
the tube is shielded by a casing and resemble other
lamp shapes including GLS, candle and spotlights.
even light distribution and this type of lamp is more
acceptable to occupants. An increasing number of
CFLi are look-alike.
Both pin-base and CFLi lamps are available in a wide
variety of outputs, making them an attractive option for
specifiers and end-users. Those using electronic control
gear – which is standard on most CFLi – reach full
output within a few seconds of switching on and there
is no flicker on start-up or in use.
CFLs should not be used with the standard domestic
wall-mounted dimmer switch. It is possible to dim
four-pin lamps, but this requires specialist control gear
and a compatible dimming controller.
CFLs usually have a working life of between 8,000 and
15,000 hours. Many manufacturers produce ‘economy’
lamps that are cheaper, but these have shorter lives
(5,000 – 8,000 hours).
Many CFLs have energy saving recommended
certification, meaning that they have been
independently tested to verify their overall quality and
the energy efficiency claims made for them. A full list is
available at www.est.org.uk/recommended
Stick lamps have the greatest efficacy and are ideal
where the lamp is not visible to the occupant e.g. in
uplighters. Longer, two-finger sticks (generally pinbased) are ideal in low profile luminaires designed to
‘wash’ surfaces. Four-finger models and ‘hoops’ are
used where a more compact lamp is desired.
Where the lamp is visible to occupants then lookalikes are preferable. Just as the diffuser of a luminaire
reduces light output, the casing may also reduce the
lamp efficacy slightly. However, there will be more
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
2.6High pressure sodium (SON) lamps
The high efficacy and very long life of these
lamps make them ideal for floodlighting. They
come in two shapes – elliptical (SON/E) and
tubular (SON/T).
However, they are not designed for frequent
switching so should not be used with
automatic presence detectors for security
lighting.
Although they are suitable for illuminating
external communal areas around housing
developments they are not normally regarded
as ‘domestic’ lighting.
2.7Metal halide lamps
Metal halide lamps are high pressure
discharge lamps that produce daylight quality
white light. This outstanding colour rendering
makes them ideal for situations where colour
perception is critical.
Newer technology ceramic arc-tube versions
offer even better colour rendering, combined
with less light loss over time and a longer
service life.
They require similar control gear to SON
lamps and cannot be frequently switched.
Although they are suitable for illuminating
external communal areas around housing
developments they are not normally regarded
as ‘domestic’ lighting.
High pressure
sodium lamps
Advantages
• Very low running costs.
• Very high efficacies: 70 – 150l/W.
• Very long life: up to 30,000 hours.
• Large choice: 50 – 1,000W.
• Universal operating position.
Disadvantages
• High purchase cost.
• Very poor colour rendering.
• Control gear required.
• Several minutes from start up to full output.
• Cannot be restarted when hot.
Metal halide lamps
Advantages
• Daylight quality white light.
• Low running costs.
• High efficacies: 60 – 100l/W.
• Very long life: from 6,000 – 15,000 hours.
• Large range of outputs: 20 – 2,000W.
• Range of colour temperatures: 3000 – 6000K.
• Several configurations: single- or double-ended and
reflector versions available.
Disadvantages
• High purchase cost.
• Control gear required.
• Several minutes from start up to full output.
• Only double-ended lamps can be restarted from hot, but
these need special control gear.
Light emitting diodes (LEDs)
LEDs are extremely small semi-conductors that emit coloured light when energised by a low-voltage
DC current. The light is in single, unmixed colours, i.e. red, orange, yellow, green or blue. If white light
is required, it has to be produced either by combining red, green and blue LEDs or by using phosphor
technology to convert ultra violet or ‘blue’ light to white.
LEDs are generally too small to be used singly, and so are supplied in arrays or modules of differing shapes
and sizes. They have very long life and fast improving efficacy (most white light LEDs are currently around
20 – 30l/W but the new generations are about 60 – 70l/W). They are highly suitable for decorative lighting,
particularly outdoors, and in emergency signage.
They are not yet developed sufficiency to be an efficient alternative for general internal lighting.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
3 Control gear
HF control gear
Advantages
• Reduce lamp energy consumption.
• Near perfect power factor.
• Silent in operation.
• Lamps start at first attempt without flickering.
• Lighter in weight than wire-wound equivalents.
• Promote longer lamp life (typically 50 per cent longer).
• Eliminate flicker and strobe effects (lamps run at
between 20 – 40kHz).
• Prevent adverse effects from variations in supply voltage.
• Automatically switch off at end-of-life, eliminating lamp
flashing.
79W
67W
55W
Saving
12W
24W
Lamp
Ballast
T12
65W
14W
15%
Existing T12
plus wire
wound ballast
T8
58W
9W
T8 plus
Class B2
ballast
18%
T8
58W*
5W
T8 plus
HF ballast
(Class A2)
Figure 4 Load savings (per cent and absolute) based on a
1,500mm long tubular fluorescent lamp and control gear.
*Rated power consumption. HF ballasts reduce actual consumption.
The Ballast Directive
Inefficient ballasts are being steadily phased out across
the European Union following the adoption of the Ballast
Directive (2000/55/EC). The Directive came into effect on
21 May 2002. It requires manufacturers to mark ballasts,
indicating their efficiency, and it bans the sale of inefficient
ballasts throughout the EU.
The main ballast categories under the Directive are:
• Class A: electronic control gear.
• Class B: ‘low loss’ magnetic ballasts.
• Class C: ‘normal’ magnetic ballasts.
• Class D: least efficient magnetic ballasts.
The sale of Class D ballasts has been banned since
21 May 2002. Class C ballasts have been banned since
21 November 2005. A date for the phasing out of the
less efficient Class B ballasts (Class B2) may be set if EU
sales of Class A ballasts do not increase sufficiently.
10
All discharge lamps (including all types of fluorescent lamps)
need control gear. It creates the right conditions to start the
discharge and to regulate the voltage and current. Different
models of lamp require specific electrical inputs – and
different control gear – to drive them. Manufacturers should
be consulted if there is any doubt about the suitability of
particular items.
The ‘conventional’ wire-wound iron-cored inductance, often
called a magnetic ballast or choke, controls the current
through the lamp and has been a standard component since
fluorescent lamps were first developed. However, it causes
a phase shift between the current and voltage resulting in
poor power factor: this is corrected by placing a capacitor in
the circuit. These components, together with a starter switch,
make up the control gear.
3.1High frequency (HF) electronic control gear
All control gear consumes electricity, but high frequency (HF)
electronic control gear uses less than half that required by
conventional wire-wound types. This, combined with the fact
that they allow lamps to run at a lower wattage for similar
light output, can result in a reduction of nearly 25 per cent
in the electricity required to run the lamp when compared
with a luminaire using a Class C ballast. (That is why Class
C ballasts are being phased out by the EU Ballast Directive
– see box.)
HF electronic control gear generally provides additional
functions such as end-of-life shutdown and it operates at
near perfect power factor (1.0). The units can either have
instant-start or pre-heat ‘soft-start’ which involves a moment’s
delay. Soft-start gear prolongs lamp life and should be used
on frequently switched lamps.
Some HF gear responds to an external signal, allowing
light output to be varied. These may be termed ‘dimming’,
‘regulating’ or ‘variable output’ control gear. They can provide
a means of reducing energy consumption when maximum
illuminance is not required, because the energy used is, in this
case, generally proportional to light output over most of the
dimming range.
Figure 4 shows the difference in connected load and the
savings to be made through changing an existing 65W T12
fluorescent tube with ‘conventional’ wire-wound ballast to a
modern 58W T8 lamp with HF electronic control gear.
Many luminaires designed for use with fluorescent lamps
are normally supplied with magnetic ballasts, although most
manufacturers offering upgrades to electronic ballasts. All
pendant-type energy efficient fittings use electronic ballasts.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
4 Luminaires for CFLs
Lighting equipment essentially consists of a lamp, controls and
control gear if needed, and a luminaire. Each contributes to
the overall efficiency. So there is no point in putting an efficient
lamp in an inappropriate fitting: always select the most efficient
components for the best overall result.
For new luminaires or pendant fittings specifically designed for
use with CFLs, the manufacturer will state the type of lamp to
be used. Where a tungsten filament lamp is being replaced by
a CFL in an existing fitting, care needs to be taken so that the
correct type of lamp is chosen – making sure that it fits into the
luminaire, see Figure 5. While several types of CFL may have
the same light output as the lamp they are replacing, they may
distribute it in different ways. For example, lamps which emit
most of their light sideways should not be placed in shades
designed to direct light vertically. By looking at a lamp from
different angles, an estimate of light distribution can be made.
In general, the amount of light emitted in any direction will
depend on the area of lamp surface visible in that direction.
Figure 5 Example of poorly matched lamp and
luminaire. The lamp was also 3500K – far too
cool for a hotel bedroom
Figure 6 gives a visual guide to light distribution from CFLs and
indicates which types to use in common luminaires. The relative
size of the arrows on the light distribution graphic shows the
proportion of light in that direction. Dedicated low energy fittings
for most applications and styles are widely available today. Many
of these have energy saving recommended certification.
A full list of energy saving recommended fittings is available
at www.est.org.uk/recommended
Images of most of these are available at
www.lightingassociation.com
CFL
Luminaire
Translucent shade
Opaque shade
Translucent cylinder
Translucent drum
Translucent sphere
Wall uplighter
Pendant/freestanding uplighter
Figure 6 A guide to light distribution from CFLs, and which to use in common luminaires
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
11
5 Standards for energy efficient lighting
5.1Building regulations requirements
The building regulations set the minimum standard
required for lighting, but higher standards and greater
efficiency can easily be achieved by adopting the
Energy Saving Trust standards (see 5.2).
The building regulation requirements for lighting
vary across the UK. All parts of the UK have lighting
requirements for ‘buildings other than dwellings’
whereas only England and Wales have requirements
for ‘dwellings’. However, Northern Ireland is expected
to adopt similar proposals to England and Wales
from June 2006. The distinction between these two
categories of buildings also varies across the UK and
advice should be sought from the local building control
body if there is any doubt.
Buildings such as student accommodation, hostels
and houses in multiple occupation are generally
classified as ‘buildings other than dwellings’ but this
will depend on the nature of the building and its size.
Guidance on how the building regulations can be met
is given in the appropriate publication (see box) for
each part of the UK.
UK legal requirements for lighting
England and Wales (dwellings)
• The Building Regulations 2000 Conservation of Fuel and
Power, Approved Document L1A: Work in new dwellings
(2006 edition).
• The Building Regulations 2000 Conservation of Fuel and
Power, Approved Document L1B: Work in existing dwellings
(2006 edition).
Scotland
• Section 6: Energy, of the Technical Handbooks on
possible ways of complying with the Building (Scotland)
Regulations 2004.
Northern Ireland
• Building Regulations (Northern Ireland) 1994, Technical
Booklet F: Conservation of Fuel and Power (December 1998)
(revised publication expected June 2006).
12
New dwellings
From April 2006 all new dwellings in England and
Wales must meet increased requirements for energy
efficient lighting. This requirement also applies to
situations where new dwellings are created as a result
of ‘material change of use’ (e.g. house conversions
and barn conversions), and to extensions to existing
dwellings.
The guidance given in Approved Document L1A
states that the requirement would be met by installing
one of the following:
•
One energy efficient light fitting per 25m2 of
dwelling floor area (or part thereof).
•
One per four fixed light fittings.
An energy efficient light fitting must comprise the
lamp, control gear, and an appropriate housing,
reflector, shade or diffuser. The fitting must be
capable of only accepting lamps having a luminous
efficacy greater than 40 lumens per circuit Watt.
Tubular fluorescent and compact fluorescent lighting
fittings would meet this requirement. Tungsten
filament and tungsten halogen lamps (both
mains voltage and low voltage) do not meet the
requirement.
These requirements mean that lighting schemes such
as those using high numbers of individual tungsten
halogen lights will significantly increase the number of
energy efficient fittings that will be required.
Lighting fixed to the external surface of the dwelling
must satisfy one of the following:
•
Only take low energy lamps.
•
Be limited to a maximum lamp capacity of
150 Watts and have controls that turn the lamp
off when there is enough daylight or when
not required at night. A fitting controlled by a
photocell and a passive infra red detector (PIR)
would meet this requirement.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
Existing dwellings
In existing dwellings the same requirements apply
when a property is extended or undergoes material
change of use. Both of these will require building
regulations approval.
Existing housing
In existing housing every opportunity should be
taken to replace existing fittings with dedicated
energy efficient ones so that 75 per cent of fittings
are low energy.
The building regulations also apply when an existing
lighting system is being replaced as part of rewiring
works. In this instance the components are more likely
to be specified by the lighting installer in conjunction
with the homeowner. In this situation the installer will
be responsible for ensuring that the required number
of energy efficient fittings are installed.
Where fittings are not being replaced then CFLi
should be used to replace standard tungsten
filament lamps wherever possible.
5.2Energy Saving Trust standards
New dwellings
For new housing there are three Energy Saving
Trust performance standards. These go beyond the
building regulations, and each standard has specific
requirements for lighting. The standards and their
lighting requirements are as follows:
•
Good practice: set just above building regulations
in specific energy efficiency areas.
•
Best practice: represents a readily achievable
higher standard and is suitable for all general
housing.
•
Advanced practice: an extremely demanding
standard aimed at exemplar housing.
Lighting requirement
Standard
Percentage of fixed
internal fittings to be low
energy*
Good practice
40
Best practice
75
Advanced practice
100
All lamps should have a colour temperature of
2700K, except for special situations.
External lighting (new and existing)
All external lighting should use one of the
following:
•
Incandescent lamps with photocells (daylight
sensors) together with presence detectors
(PIRs) and have a maximum lamp capacity
of 150W.
•
Energy efficient lamps (efficacy of at
least 40l/W) and compatible photocell or timer.
Full details of these standards can be found
on the Energy Saving Trust website at:
www.est.org.uk/housingbuildings/standards
Recessed fittings and airtightness
As of April 2006 a key requirement for
builders in England and Wales will be
to ensure that new homes reach a set
airtightness standard.
Using large numbers of recessed light fittings
can significantly worsen the airtightness of a
dwelling even if care is taken.
* i.e. fittings that will only accept lamps with a
luminous efficacy of greater than 40 lumens
per circuit Watt. Excludes fittings in garages and
cupboards.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
13
6 Opportunities for energy efficient lighting
In conventional housing, the opportunities for
introducing more energy efficient lighting – and
experiencing the benefits – vary from house to
house and even room to room. This section outlines
ways of improving lighting and saving energy.
More information on specific situations is given in
Low energy domestic lighting – looking good for
less (CE81/GPCS441) (see Further reading).
The energy efficiency of the lighting in a
dwelling can be improved at different times in
its life regardless of whether building regulations
compliance is required. Clearly, the construction
phase provides the opportunity to address
the issue in a coordinated and thorough way,
but there are also opportunities as a home
is redecorated, either on a room-by-room
basis or as part of a larger refurbishment.
Wiring should be inspected every 10 years or
when there is a change of occupancy, and
this too provides an occasion for the electrical
contractor to suggest alternative lighting
layouts and to advise home owners or building
owners on the choice of equipment.
6.1Lighting design
When considering alternative lighting arrangements
or styles, it is important to recall the basic principles
of lighting design. Designers divide lighting into
three types:
•
General – such as a central hanging light.
•
Task lighting – for example, a desk or table lamp.
•
Atmospheric or ornamental – such as a spotlight on
a picture.
The following guidelines can help in making the
correct choices:
•
Decide what the lighting is really needed for; then
design a scheme and choose the position of the
lights where they will be used. Include task lighting
and provide sockets for reading lights.
•
Direct light where it is required.
•
Use lamps appropriate for the fitting.
•
Use lighting to aid safety.
•
Use lighting for effect – reduced background
lighting will create more contrast in a room as well
as saving energy.
Direct light to where it is required
An important principle of energy efficient lighting design is to make the most of any light sources available
by directing the light to where it is needed. It can often happen that a room – or even the whole house
– is lit to a uniform level but an individual may not have enough light for a particular detailed task, such
as reading, sewing or writing. This is clearly an inefficient use of resources. Outdoors, uncontrolled light
emitted upwards is wasted and also the cause of ‘light pollution’, which reduces visibility of the night sky.
14
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
6.2Lighting control
•
If each fitting has its own switch it can be
switched on and off independently when
needed.
•
If switches are conveniently situated, occupants
will be more inclined to switch lights off when
not required.
•
Dimmers can be used to vary lighting in an
energy efficient way (depending, for example,
on daylight levels). Ensure that the dimmer,
lamp (and the control gear if needed) are all
compatible (see Section 7).
•
Use automatic controls where appropriate.
Hallways
A central fixture can provide a warm reception for
visitors. Flush ceiling fittings maximise headroom
in this often small area. Fluorescent lamps are
particularly suitable here as their low running
temperatures reduce potential heat build-up in
flush fittings.
Since hallways are generally lit for long periods, the
use of low energy lighting will maximise savings.
A warm lamp (2700K) should be specified.
CFLs with a colour temperature of 2700K should be
specified, unless tungsten halogen lamps are also
used in the same room, when 3000K lamps may be
more appropriate.
Dining rooms
Lighting can be used to create different ‘moods’. A
wash of light over one wall or the ceiling can provide
a background level of lighting against which a variety
of lighting effects can be achieved using portable
luminaires. The wash can be created using tubular
fluorescent lamps shielded in such a way that light is
directed down the wall or across the ceiling.
The light level can be varied with compatible dimming
equipment. The use of high frequency control gear will
not only eliminate flicker on start-up and in use, but
will also eliminate the low-level hum that wire-wound
control gear causes.
The very long life of tubular fluorescent lamps means
that dust can build up and an occasional wipe with a
dry cloth may be required. Ceiling-mounted spotlights
or low hanging pendant fittings can be used to
light the table if required. These should be switched
independently of the other lighting.
Living rooms
Living rooms need a relaxed atmosphere and some
flexibility in lighting provision: this requires a variety
of light sources. Avoiding glare from the lamps is
also important and wall lights such as uplighters can
meet this need.
Central, flush ceiling luminaires will also reduce glare
by hiding the light source. There is a wide range of
fittings designed for use with CFLs.
The room’s long hours of use mean that CFLs will
achieve significant energy and cost savings. Good
ambient background lighting can be supplemented
by portable fittings such as table or standard lamps,
which provide the higher localised levels of lighting
required for reading or other detailed activities.
Figure 7 Dimmable fluorescent lighting ‘built in’ to a
room can create a variety of moods
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
15
Kitchens
The detailed tasks being carried out in a kitchen
require high levels of lighting, particularly since
many of activities involve the use of sharp tools.
Fluorescent lighting under kitchen cabinets provides
this and helps to reduce risk to people who might
otherwise be working in their own shadows
in a centrally lit room. Where lighting is used to
supplement daylight, a cool colour temperature
(3500-4000K) can be chosen.
Recessed low energy downlighters can be
used away from the work surfaces to provide
background lighting and to illuminate eating areas.
Separate switching should be provided. However,
recessed fittings can have a significant impact on
the airtightness of a dwelling if they are not very
carefully installed and allowed for in the design
(e.g. by the use of service voids).
Stairs and landings
As in the case of hallways, flush fittings maximise
headroom in these ‘transit’ areas, but there are also
other issues to consider. Stairs must have adequate
lighting and this will generally require luminaires
either along them or above them – or in close
proximity on the landing. The risks of falls associated
with replacing lamps can be reduced considerably by
using CFLs because they have a much longer service
life than incandescent lamps.
Bedrooms
While providing good general light levels, bright
central light sources can create glare for occupants
reclining in bed. This can be reduced by directing
lighting onto surfaces. Providing a separate circuit
specifically for bedside lighting, with lighting socket
outlets and two-way switching, will help to ensure
that lights are not left on unnecessarily.
Figure 8 Under-cabinet lighting improves safety on work surfaces as
well as having a high degree of permanence
Bathrooms
Although bathrooms are not lit for long periods, the
use of low energy lighting with a long service life
can be particularly appropriate for enclosed fittings
where lamps may be difficult to replace.
Studies
Harsh lighting can create glare on computer screens
and paper-covered desks. This can be avoided
by arranging a low level of background light: CFL
dedicated wall uplighters can be used to create a
general wash of light.
Figure 9 Use of a CFL in a double height space to reduce risk of falls
16
Lighting the surface behind a computer monitor will
reduce eye strain. A desk lamp directed at the wall
will achieve this (many modern models will only
take CFLs). As these are often positioned close to
the user, the low running temperature of a CFL will
improve comfort.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
Style and permanence
To achieve long-term savings, energy
efficient lighting fittings should only be
able to accept high efficacy lamps and
they should not be easy for occupants
to remove. This is particularly important
when dwellings are being built or when
they are being refurbished before sale:
the tastes of the new occupants are
unlikely to be known.
To minimise the risk of them being
removed, select fittings that do not
make a strong style statement – plain
uplighters, for example, or fittings that
have interchangeable shades. However,
the best solution is to provide discrete
lighting that is part of the fabric of the
building or part of the fixtures. This
could include under-cabinet lighting,
pelmet lighting, etc.
External lighting
The selection of external lighting will largely depend upon its
purpose and the way it is to be used. Where lighting is only
required for short periods – for example to light a path while it
is in use – then a standard incandescent lamp may be suitable,
provided it has adequate controls. These might include a
photocell (to prevent the light being used in daylight) and a
presence detector.
The use of 300-500W tungsten halogen flood lamps is
not recommended for most domestic situations. They are
comparatively expensive to run and, if badly sited, can give rise
to light pollution as well as dazzling passing pedestrians and
motorists. In domestic settings a 150W lamp (with appropriate
controls) is usually sufficient. If not, it is preferable to install two
separately controlled fittings.
Low energy light sources such as CFLs should be used where
the lighting is required for longer periods. Ideally, these would
also be controlled to prevent use when not required (with
timers and photocells, for example). However, care should be
taken to ensure that any controls are compatible with CFLs.
Portable luminaire
Controlled external
lighting
Built in tubular
fluorescent
Recessed
downlighters
Directional task
lighting
Tubular fluorescent
under cabinet
Uplighters
Flush ceiling fitting
Figure 10 Opportunities for low energy lighting in housing
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
17
7 Dimming
The mood of the lighting can be changed easily
by dimming. Dimmed to 25 per cent of full
light output, a lamp – or the lit area – is likely to
appear about half as bright. When dimmed to
just 10 per cent, it will appear about one third as
bright. This effect is due to adaptation. There may
be a noticeable change in the apparent colour of
the light from a tungsten lamp – to a warmer tone
– but fluorescent light will appear the same.
A dimmer must only be used with the type of lamp
for which it is designed. It must match the lamp, the
control gear or transformer, and the load current.
7.1 Dimmers for incandescent lamps
Modern domestic phase-cut dimmers for use with
incandescent lamps do save energy. A tungsten
filament lamp dimmed to half light output, for
instance, will consume about 40 per cent less
electricity and lamp life will be extended by up
to 10 times. However, lamp efficacy (l/W) will be
reduced by 30 per cent.
Not all transformers used with extra low voltage
(ELV) lamps are compatible with domestic
phase-cut dimmers. Transformers for ELV lamps
18
should state whether or not they are dimmable, but
the best advice is to check with the manufacturers
of both. Some types of transformers will need a
pre-heat (soft-start) dimmer in which the lamp is
always on, albeit in a dimmed state. In addition,
some transformers may cause electromagnetic
interference when used with domestic phase-cut
dimmers. Lamp-flicker may also occur.
Laminated, open wire-wound transformers, and
some electronic transformers, are most likely to
be compatible with phase-cut dimmers. Most
electronic transformers, though, require dimmers
that are compatible with inductive loads.
7.2Fluorescent lamps
Two-pin fluorescents and CFLi cannot be dimmed.
All tubular fluorescents and four-pin CFLs can be
dimmed with specialist control gear, but not always
to extinction. Most HF dimmable control gear will
only allow dimming down to 1 per cent of full
light output. Over most of the dimming range, the
percentage energy savings roughly equates to the
reduction in light output for electronic HF dimming,
regulating and variable output control gear.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
8 Glossary
Adaptation
The process which takes place as vision adjusts
to the brightness or the colour of the visual field.
Ballast
A component of conventional control gear.
It is an inductance which controls the current
through the lamp. The term is sometimes
used loosely to mean control gear.
Choke
Alternative name for ballast.
Colour rendering
An indicator of how accurately colours can be
distinguished under different light sources. The
colour rendering index (measured in Ra) compares
the ability of different lights to render colours
accurately with an Ra of 100 being ‘ideal’.
Colour temperature
The colour temperature provides an indication
of the light colour and is expressed in
Kelvin (K). Most lamps are rated between
2700K (warm) and 6500K (daylight).
Connected load
The total load connected to the mains including
lamp, control gear, transformers, etc.
Control gear
A ‘package’ of electrical or electronic
components including ballast, power factor
correction capacitor and starter. High frequency
electronic control gear may include other
components to allow dimming, etc.
Dedicated fitting/luminaire
A lighting outlet that will only accept
an energy efficient lamp so preventing
the use of less efficient lamps.
Diffuser
A translucent screen used to shield a light
source, at the same time softening the
light output and distributing it evenly.
Discharge lamp
A lamp whose illumination is produced by
an electric discharge through a gas, a metal
vapour or a mixture of gases and vapours.
Efficacy (luminous efficacy)
Strictly speaking, the term ‘efficacy’ compares
two quantities with the same units e.g. Watts
output to Watts input. However, light output is not
normally measured in Watts (the Wattage ratings
on lamps are measures of the electrical input or
consumption), so it is actually correct to refer to a
lamp’s luminous efficacy – the ratio of the lumens
(light) emitted by the lamp compared to the
power consumed – which is expressed in ‘lumens
per Watt’ (l/W). When the control gear losses are
included it is expressed as lumens per circuit Watt.
Extra low voltage (ELV)
Refers to anything under 50V. Electrical engineers term
‘mains’ voltage as low voltage (50-1,000V) because
they are used to dealing with voltage levels of 1,000V
and above. (There is a further category, safety extra
low voltage (SELV) which refers to supplies also under
50V but supplied through an isolating transformer.)
General lighting
Lighting of a whole area.
Illuminance
The amount of light falling on a surface of
unit area. The unit of illuminance is the lux,
equal to one lumen per square metre.
Lumen
Unit of luminous flux, used to describe the amount
of light produced by a lamp or falling on a surface.
Luminaire
The correct term for a light fitting. An apparatus
which controls the light from a lamp and includes
all components for fixing and protecting the lamps,
as well as connecting them to the supply.
Operating position
The orientation or plane in which a lamp
is used. A lamp with a universal operating
position can be used in any plane.
Power factor
The ratio of real power (Watts) to apparent
power (volt-amps). The higher the power factor
the better, 1 (unity) being the maximum.
Rated average lamp life
The time when half the number of lamps
in a batch failed under test conditions.
Energy efficient lighting – guidance for installers and specifiers (2006 edition)
19
CE61
Further information
The Energy Saving Trust sets energy efficiency standards that go beyond building regulations,
for use in the design, construction and refurbishment of homes. These standards provide an
integrated package of measures covering fabric, ventilation, heating, lighting and hot water
systems for all aspects of new build and renovation. Free resources including best practice guides,
training seminars, technical advice and online tools are available to help meet these standards.
The following publications may also be of interest:
•
Domestic Lighting Innovations (CE80/ADH001)
•
Low energy domestic lighting (GIL20)
•
Low energy domestic lighting – looking good for less (CE81/GPCS441)
To obtain these publications or for more information, call 0845 120 7799,
email [email protected] or visit www.est.org.uk/housingbuildings
Relevant organisations and websites
BEAMA Installation Ltd
Tel 020 7793 3013 www.beamainstallation.org.uk Electrical Contractors’ Association
Tel 0207 313 4800 www.eca.co.uk
Lighting Association
Tel 01952 290905
www.lightingassociation.com National Inspection Council for Electrical Installation Contracting (NICEIC)
Tel 0870 013 0391
www.niceic.org.uk SELECT (previously The Electrical Contractors’ Association of Scotland)
Tel 0131 445 5577
www.select.org.uk Energy Saving Trust, 21 Dartmouth Street, London SW1H 9BP Tel 0845 120 7799 Fax 0845 120 7789
[email protected] www.est.org.uk/housingbuildings
CE61 © Energy Saving Trust March 2004. Revised March 2006. E&OE
This publication (including any drawings forming part of it) is intended for general guidance only and not as a substitute for the application of professional expertise. Anyone using this
publication (including any drawings forming part of it) must make their own assessment of the suitability of its content (whether for their own purposes or those of any client or customer),
and the Energy Saving Trust cannot accept responsibility for any loss, damage or other liability resulting from such use. So far as the Energy Saving Trust is aware, the information presented in
this publication was correct and current at time of last revision. To ensure you have the most up-to-date version, please visit our website: www.est.org.uk/housingbuildings/publications. The
contents of this publication may be superseded by statutory requirements or technical advances which arise after the date of publication. It is your responsibility to check latest developments.
All technical information was produced by BRE on behalf of the Energy Saving Trust.
Printed on Revive Silk which contains 75% de-inked post consumer waste and a maximum of 25% mill broke.

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