Understanding lighting - how to know
more than the salesperson!
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Lighting - the Basics
Lumens – The amount of light that is emitted
Lux – A measurement of the amount of light over a
given area. Measured in Lux/M2
1 lux = 1 lumens per m2
Efficacy – The ratio of light output to power input
Measured in lumens per watt
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Lighting - the Basics
The efficacy of a 50W down light emitting 900 Lux
would be 900/50 = 18 lumens per watt
In contrast a 10 Watt LED bulb emitting 900 Lux would
have an efficacy of 90 Lumens per watt
And this figure for LED is getting better all the time
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Lighting - the Basics
Efficiency – The percentage of power converted to light
A GLS (General Light Service) or “Incandescent” bulb has an
efficiency of 2% as it converts most of the input power to
heat.
A halogen downlight has is about 3.5% efficient and LED is
now about 80%
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Lighting - the Basics
Colour Temperature – it is a measure in degrees Kelvin that
indicate the hue of a light source.
The warmer the colour the closer to red it gets.
Compact Fluorescent Lamps have a bad reputation for being “too
blue”. This is because it has a high colour temperature (6,0000K) as
opposed to a GLS light bulb which is a warm-white (2,5000K)
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Lighting - the Basics
Colour Rendering Index – It is a measure of how well
a light source can accurately display colours
compared to natural light. It is expressed as
percentage. The higher the CRI the more accurate
the colours will be displayed
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Lighting - the Basics
Beam Angle- it is the outer angle of the light emitted
form the light source. A halogen downlight typically has
a 60º beam angle.
Some LED replacements may only have a 22 or 30
degree beam angle
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Lighting: MEPS
• Federal program to increase the efficiency of certain
appliances
• Issued a ban on the production or importation of GLS
bulbs in 2009
• Last year banned the importation of Dichroic
(halogen) bulbs over 37 Watts
• Those of you with 50 W downlights should start
thinking about an alternative
• Be careful with LED retrofits
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Lighting: Section J
• Section J of the National Construction
Code (formerly Building Code of Australia)
refers to sustainability and energy
efficiency
• Applies to all new builds or renovations
greater than 25%
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Lighting: Section J
• 5W per square metre inside a class 1
building (House or unit)
• 4W per square metre outside
• 3W per square metre in class 10 buildings
(garages etc.)
• Applies to the total area of the building
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Lighting: better practice
A builder’s attempt at 5W per square
metre
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Lighting: better practice
Replaced 50W downlight with 20W LED
disc Light.
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Lighting: Halogen lamps
Low voltage halogen lamps
A form of incandescent light that can generate a lot of heat
(up to 300degrees!)
Inefficient iron core transformers can use as much as 15w.
High efficiency electronic transformers are now on the
market only using as much as 2 to 3 watts.
Low voltage does NOT
mean low energy
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Lighting: low-energy options
• Fluorescent lamps are efficient and versatile
form of residential lighting
– They use only about one quarter of the energy of
normal incandescent bulbs
– Compact fluorescent lamps (CFLs) are the most
versatile, although not quite as efficient as linear
and circular types
– They have a small amount of mercury in them which
makes disposal problematic.
– They should not be put on motion detectors as it
will seriously reduce their lifespan
– But they can look seriously ugly
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Lighting: CFL options
CFLs are available in a wide range of styles
They can replace almost any style of incandescent lamp
They can replace almost any style of incandescent lamp
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Lighting: CFL downlights
CFL downlights are available that avoid
some of the problems with low voltage
halogen downlights
Source: Cosmo Luce lighting
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Lighting: low-energy options
• LED lamps are emerging as another viable and
highly efficient form of lighting and will eventually
supercede most incandescent and fluorescent
technologies.
• They have high efficacy, long life (40,000 hours plus)
and can come in a variety of colour temperatures.
• Many of the newer LED lights are achieving CRIs
close to incandescent bulbs.
• They do not emit UV so they don’t attract insects
• Ideal for running on motion detectors
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Lighting: LED options
LEDs are also available in a wide range of styles
LEDs are also available in a wide range of styles
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Lighting: CFL downlights
LED downlights will be the way of
the future
Source: EcoDecisions
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Lighting: costs in use
7W
LED
Bulb
23W
CFL*
4 x 35W
halogens*
4 x 50W
halogens
Average usage per
day
4 hours 4 hours 4 hours
4 hours
Electricity used per
year
10 kWh 34 kWh 234 kWh**
350kWh
Cost per year
(@30c/kWh)
$3.00
$10.20
$70.20
$101.00
CO2 produced per
year
13.5 kg
45.9 kg
316 kg
473 kg
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Lighting: costs over lifetime with
lighting alternatives
12v LED 7W
23W CFL
4 x 50W MR 16
Halogens*
Lifetime hours
50,000
8,000
2,000
Purchase cost
Over 10 years
Lamps required
$20
$3.20
(proportion)
$9
$18
(2 lamps)
$12
$96
(32 lamps @ $3)
Electricity
used kWh
100
340
3500
Running cost
over 10 years
@ 30 c/kWh *
$47.70
$162
$1,669
Total cost
$50.90
$180
$1,765
CO2 produced
56 kg
200 kg
1316 kg
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Lighting: better practice
Courtesy of Kennedy Associates Architects
Reduce the need for artificial lighting:
• Make use of natural light
• Use energy efficient skylights and
windows
• Decorate with light coloured
finishes and furnishings
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Lighting: better practice
Courtesy of Kennedy Associates Architects
Many builders and electricians don’t
know how newer LED lights will
behave in a building.
You can get a lighting plan done which
will show the illumination levels in a
room
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Courtesy of Kennedy Associates Architects
Lighting: better practice
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Lighting: natural options
Small clerestory windows can provide lots of
light without much heat gain: this is 1 square
metre, and lights a whole room
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Lighting: Be energy smart
• Provide multiple switches
• Use ‘smart’ light switches
• Use controls to switch on and off
automatically
• Dimmer controls
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Outdoor lighting
Use efficient lighting
Use controls to switch on and off
automatically with motion and light detectors
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Questions?
www.ecodecisions.com.au 0404 538822