6.3 LIGHTING
Household lighting energy use in Australia has been rapidly increasing in recent years due to the construction of larger homes and the installation of more light fittings per home. Most homes could reduce the amount of energy they use for lighting by 50 per cent or more by making smarter lighting choices and moving to more efficient technologies.
In February 2007 the Australian Government announced plans to phase-out inefficient lighting technologies where viable energy efficient alternatives exist by introducing minimum energy performance standards (MEPS).
A range of lighting types are, or will be, required to meet these MEPS and be registered with relevant state regulatory authorities to be legally sold in Australia.
Under the first stage of the phase-out of inefficient incandescent lighting, an import restriction on traditional pear shaped light bulbs used for general lighting services came into effect from 1 February 2009, followed by a sales restriction from 1 November 2009. This sales restriction also applies to compact fluorescent lamps (CFLs) and extra low voltage (ELV) halogen non-reflector lamps that are not compliant with Australian Standards.
Other lamp types were required to meet the Standards from October 2010. The phase-out schedule can be viewed at www.climatechange.gov.au/what-you-need-to-know/lighting.
Good lighting is about more than just light levels. The same level of light can provide effective or ineffective lighting. Some lighting can make rooms flat and featureless even when it’s bright. A lighting designer will be able to help you design more effective lighting, but make sure they know you also want an energy efficient system.
An efficient and effective lighting system will:
- Provide a high level of visual comfort.
- Make use of natural light.
- Provide the best light for the task.
- Provide controls for flexibility.
- Have low energy requirements.
TYPES OF LIGHTS
Incandescent lamps
lncandescent lamps or bulbs have for many years been the most commonly used type of lighting. They work by heating an electric element to white hot. They are inexpensive to buy and are available in a wide range of shapes and sizes, but their running costs are high.
Incandescent lamps are the least energy efficient type of lighting, and are being phased out where ever possible over the next few years.
Almost all of the electrical energy used by incandescent lamps is converted into heat rather than light. Standard incandescent bulbs only last about a thousand hours and must be regularly replaced. Incandescent lamps are most suitable for areas where lighting is used infrequently and for short periods, such as laundries and toilets.
Incandescent spotlights have built-in reflectors that reflect the light forward. Light output decreases over time as some of the tungsten in the filament evaporates and coats the glass bulb.
Halogen lights are also a type of incandescent lamp. The halogen gas in the bulbs prevents evaporated tungsten from depositing on the glass bulb. They are more expensive to buy but last up to four thousand hours. They can be either mains voltage bulbs (240V) or low voltage bulbs (typically used in downlighting).
A number of manufacturers are now producing traditional pear shaped lamps containing a halogen bulb. Although more efficient than traditional incandescent lamps, these still use much more energy than a fluorescent lamp. A 60 Watt standard lamp can be replaced by a 42 Watt halogen or a 12 Watt CFL for the same light output.
Ceiling fires have increased significantly with the more common use of downlights that penetrate the ceiling. Care must be taken to ensure that minimum clearances around downlights are maintained and that transformers are not underneath the insulation. Wherever possible, avoid recessed light fittings as these are a major source of heat loss. [See: 4.8 Insulation Installation]
Low voltage halogen lamps (commonly known as downlights) are not low energy lamps. While they are slightly more efficient than standard incandescent lamps of the same wattage, large numbers of these lamps are required to light a room because they emit a narrow beam of light. Each downlight also requires a transformer that can consume an additional 10 to 15 Watts on top of the bulb energy.
More efficient electronic transformers are available which use only a few Watts.
Because they are designed to be spot lights, downlights are not appropriate for general room illumination. They are most suitable for highlighting features such as paintings or for task lighting directly over a cooking area or study desk. If using downlights, fit lower wattage and more efficient bulbs. Efficient 35W lamps are available that produce as much light as a standard 50W lamp. You may even be able to replace a 50 Watt lamp with a 20 Watt lamp. Compact fluorescent lamps and LEDs designed for down lighting are an energy efficient alternative that should be considered.
Large numbers of low voltage halogen lamps are often fitted to light large spaces – this is an inefficient way to light a room and results in unnecessary energy consumption both through the lights themselves and the heat loss due to the holes in the ceiling and gaps in the insulation.
Fluorescent lamps
Compact fluorescent lamps (CFLs) and linear or tubular fluorescents lamps are the most energy efficient form of lighting for households. Fluorescent lamps use only about one quarter of the energy used by incandescent bulbs to provide the same light level.
Fluorescent lamps work by causing a phosphor coating in the inside of a glass tube to glow. Different types of phosphor emit different coloured light.
Although more expensive to buy, fluorescent lamps are much cheaper to run and can last up to twenty thousand hours. With careful design they can replace incandescent and halogen lights in most situations.
Fluorescent lamps are ideal for areas where lighting is required for long periods of time, such as the living room and kitchen, and for security lighting. They also produce less heat, helping keep your home cooler in summer.
There is much greater variation in the quality of fluorescent lamps sold in Australia than there is for other lighting types. In the past some poor quality fluorescent lamps were sold. To counter this, at the same time as bringing in regulations to phase out inefficient lighting the Government introduced a performance and quality standards for compact fluorescent lamps.
Fluorescent lamps are a developing technology and there have been many improvements in the performance of both linear and compact fluorescents lamps (CFLs) in recent years. Fluorescent lamps that cover a range of desired colours, including the ‘warm’ light of most incandescent globes (around 2700° Kelvin) are readily available. Cool white tubes have a higher colour temperature (around 5000° Kelvin), and are better suited to garages and workshops. A lamp of 3000°K to 3500°K is most appropriate for replacing halogen lamps. By selecting the appropriate wattage and colour fluorescent lamp a large range of lighting effects are achievable. When mixing different types of lighting in a room try to use similar colour temperatures.
There are two main types of fluorescent lamps – tubular and compact.
Tubular lamps, also known as fluorescent tubes, are available in a straight or circular style. They are cheaper to buy than CFLs, but unlike CFLs require special fittings. Tubes are ideal for kitchens, garages and workshops.
CFLs, also known as long-life bulbs, are usually designed to fit into conventional bayonet or screw fitting light sockets and so are the ideal replacement for inefficient incandescent bulbs. They come in a wide range of shapes and can replace incandescent lamps in most fittings, including heritage lighting and downlights.
CFLs can replace incandescent light bulbs in many light fittings. Not all light fittings are suitable for conversion to CFLs but most can be successfully converted with the right choice of lamp.
Most CFLs cannot be used with conventional light dimmers, but some can. Others have built in 'step' dimming, operated by the light switch. If you need to dim them make sure you buy the right lamp.
CFLs take a short time to reach full brightness - this varies from lamp to lamp but has improved with the new quality standard recently introduced. In situations where you need bright light instantly, such as in stairwells, you may wish to choose a brighter CFL. Look for one with a short start up time or use a halogen lamp.
Ballasts
All fluorescent lamps need a ballast to start them. For tubes, the ballast is separate and usually located in the light fitting. CFL ballasts are generally built into the lamp base. However, some CFLs have a separate tube and ballast. As the ballast is more expensive and lasts longer than the tube, the tube is detachable and can be replaced when it fails. Few domestic light fittings are currently specifically designed for separate ballasts, although desk lamps and some surface mounted models are available.
Ballasts can either be older magnetic types or newer electronic versions. Electronic ballasts are more expensive to buy, but are more energy efficient. They also start the lamp more quickly, produce less flicker and make the lamp last longer.
Magnetic ballast lamps cannot be dimmed, but some electronic units can.
Light Emitting Diodes (LEDs)
LEDs are currently used in countless applications including lighting displays in household appliances, mobile phone screens, and traffic signals.
LEDs for general lighting purposes are an emerging lighting technology which is expected be the future of household lighting. Most lighting companies are developing LED bulbs for direct replacement into normal fittings, and a wide range is expected to be available in the next couple of years.
The claimed benefits of LEDs include lifetimes of up to 100,000 hours and potentially very high efficiency levels. However, there is currently a wide range of claimed efficiency levels on the market for LEDs and no agreed standard on how to measure the efficiency and light quality. The performance of some LED lamps is over-stated. The best LEDs on the market at the moment are about the same efficiency as CFLs.
One big advantage of LEDs is that in some cases they can be a direct replacement in low voltage halogen downlight fittings without needing any wiring changes. Before replacing halogen fittings with LEDs, you will need to check the compatability with your existing downlight transformers.
If buying LEDs, choose a well known brand and look closely at the performance figures to make sure you would not be better off with a fluorescent equivalent.
Some current LED models have poor light quality and low light output but they are rapidly improving. LEDs can also be more expensive but as technology improves and demand increases, costs should come down
Comparison of lighting costs
The cost of running a light is directly related to the wattage of the globe plus any associated ballast or transformer. The higher the wattage, the higher the running cost.
CFLs are the cheapest form of household lighting when the life cycle cost is considered.
The type of lighting you choose will affect the amount of electricity you use, your lighting bill and your greenhouse gas emissions.
EFFICIENT LIGHTING CHOICES
Choose the right light
The most energy efficient light is natural light. Well designed north-facing windows, skylights and light tubes let in light without adding to summer heat and winter cold. Light coloured interior surfaces, especially in south-facing rooms and hallways, reflect more light and reduce the level of artificial lighting required.
Most rooms need two types of lighting. General lighting is needed for all over illumination. Task lighting is used to illuminate specific areas, such as benchtops and desks. Different light bulbs and fittings should be used for these two purposes. Accent lighting can also be used for decorative or dramatic effects.
Pendant or surface-mounted light fittings can be used to provide general lighting. Use desk, table or standard lamps where most light is needed, such as for reading, so less lighting is required in the rest of the room.
Use fluorescent lights where lighting is required for long periods of time, such as living rooms, over kitchen benches or on desks.
The light output of CFLs is reduced at low temperatures, so they may not be suitable for outside use in very cold areas, or you may need to use a higher wattage lamp.
Incandescent lamps are inefficient and so will not be available in the future for general lighting. However, some specialty use incandescents will continue to be sold until energy efficient alternatives become available.
Downlights are designed for spotlighting as they provide bright pools of light rather than general illumination. Up to six downlights may be required to light the same area as one pendant light. Think about other ways of lighting with fluorescents before installing halogens. If used, fit lower wattage and more efficient bulbs.
Choose light fittings that allow most of the light through so a lower wattage lamp can be used. Some light fittings can block 50 per cent or more of the light.
Switches and controls
Provide multiple switches to control the number of lights that come on at any one time. Using one switch to turn on all the lights in a large room is very inefficient. Place switches at the exits from rooms and use two-way switching to encourage lights to be turned off when leaving the room.
‘Smart’ light switches and fittings use movement sensors to turn lights on and off automatically. These are useful in rooms used infrequently where lights may be left on by mistake, or for the elderly and disabled. Make sure they have a built-in daylight sensor so that the light doesn’t turn on unnecessarily. Models which must be turned on manually and turn off automatically, but with a manual over-ride, are preferable in most situations.
Use timers, daylight controls and motion sensors to switch outdoor security lights on and off automatically. Similar controls are particularly useful for common areas, such as hallways, corridors and stairwells, in multi-unit housing.
Some controls are not compatible with fluorescent lamps so make sure you buy one that is.
Consider using solar powered lighting for garden and security lights.
Modern dimmer controls for incandescent lights (including halogens) save energy and also increase bulb life. However, reducing light output to 50% will only save about 25% of the energy. If you find that you dim some lights most of the time, you would be better off replacing them with lower wattage bulbs.
Most standard fluorescent lamps cannot be dimmed, but special dimmers and lamps are available. When installing new light fittings and controls ensure they are compatible with CFLs.
Use lights efficiently
- Rooms are often excessively lit. Make sure you are not using a higher wattage bulb than is necessary.
- Turn off unnecessary lights, including fluorescent lamps, especially if leaving a room for more than ten minutes.
- Clean light fittings regularly to allow more light to pass through.
- Decorating with light coloured finishes and furnishings can allow lighting levels to be reduced.
- Install lights appropriate for the location - ideally maximising natural light, reducing the number of holes in the ceiling and insulation, and with switches in easy-to-use locations.
| ADDITIONAL READING |
|---|
| Contact your State / Territory government or local council for further information on energy efficiency. www.gov.au |
| Australian Consumer Association www.choice.com.au |
| Department of the Environment, Water, Heritage and the Arts (2008), Energy Use in the Australian Residential Sector 1986-2020 www.energyrating.gov.au/library/details2008-energy-use-aust-res-sector.html. |
| Energy Efficient Lighting, Australian Government www.climatechange.gov.au/what-you-need-to-know/lighting |
| Lighting Council Australia www.lightingcouncil.com |
| ReNew: technology for a sustainable future magazine, Lighting Buyers Guide, Issue 94 www.renew.org.au |
| The Basics of Efficient Lighting - Lighting Reference Manual, www.energyrating.gov.au/library/details2009-ref-manual-lighting.html |
Principal authors:
Geoff Milne, DCCEE
Contributing author:
Chris Riedy
Last updated: November 2010