There are numerous initiatives which can improve the energy efficiency of lighting. An effective strategy relies on an integrated approach incorporating the following strategies.

Reduce demand for artificial lighting

There are several highly effective strategies to maximise the amount of natural lighting, referred to as ‘daylighting’ a building. Techniques include the use of light-coloured internal surfaces, skylights, shading device control, glare reduction and electrochromic glazing. When combined, these strategies can yield significant energy savings by minimising the need for artificial lighting.

Reducing, or in some cases, eliminating demand for an energy using service is an excellent strategy to use in tandem with administering the overall system more efficiently.

Some examples of opportunities in this area are outlined below.

Implement daylighting strategies

Using daylight to reduce the need for artificial lighting can be as simple as opening the blinds in the morning, or may require installation of windows or skylights. Even where tasks require a high lighting level, daylight can often be used to provide background illumination supplemented by task lighting.

As well as saving energy, daylight has been shown to increase productivity in industry, offices and schools, and to increase retail sales. The full colour spectrum in daylight improves and facilitates more accurate colour-matching (e.g. in retail and some production processes).

Further efficiencies can be gained by combining natural daylighting with optimised systems, such as movement-activated light sensors and timed lighting controls.

Tip: Control direct sunlight to exclude unwanted radiant heat and glare by choosing appropriately glazed/reflective-film glass windows and shading options. This will mitigate against staff or occupants wanting to keep blinds shut much of the time.

Also consider relocating workstations, tasks or activities to areas that are daylit or have artificial lighting serving another task. This can reduce the amount of electric lighting required. Scheduling activities to times of day when there is ample daylight, or when an area would be lit for another purpose, can reduce the need for additional lighting.

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Use light coloured surfaces or window glazing

Light coloured, reflective ceilings, walls, partitions and floors will improve the utilisation of light within a space reducing the amount of artificial lighting required for a task. Using light coloured surfaces may be a no-cost decision during construction or refurbishment, or may require an additional capital investment if undertaken in an existing building purely for energy efficiency. After lightening colours, lighting efficiency can be further improved by implementing strategies to optimise or upgrade lighting.

Another option is electrochromic glazing for windows. This new generation of ‘smart’ windows uses technology which adjusts light transmittance and glass transparency via an electric current. Electrochromic windows (also known as switchable glazing)  can automatically control and enhance interior lighting conditions, saving energy and increasing comfort levels.

Optimise the use of existing lighting systems

Many lighting efficiency opportunities can be easily implemented with little or no capital or the need to redesign a lighting system—such as turning lights off when not needed. These easily implemented actions can kick-start your lighting energy efficiency program, resulting in rapid cost savings and positive staff engagement.

Some examples of opportunities in this area are outlined below.

Turn lights off manually when not required

Encouraging staff to turn lights off when not required (e.g. when leaving a room or when there is sufficient daylight) can result in significant energy savings. It is also a good way to raise staff awareness of the company’s sustainability strategies. To encourage staff to turn lights off:

  • Explain that leaving fluorescent and discharge lights on does not save energy.
  • Where lights in several areas are all controlled from the same bank of switches, provide a clear, colour-coded diagram of the area served by each switch and instruct people to turn on only the lights they require.

Enabling staff to turn lights off may involve improvements that require an investment, such as:

  • Installing light switches in individual offices, costing approximately $40–$80 per switch installed, depending on number installed
  • Rearranging lighting circuits to align with work areas or to group lights in daylit areas
  • Replacing discharge lights (e.g. mercury vapour) with lights with a short restrike time. This will cost between $20 per unit (replacing self-ballasted mercury with compact fluorescent) to about $150 per unit (replacing ballasted mercury vapour fittings with new compact fluorescent or LED light fittings).
Myth: Leaving the lights on uses less energy
Probably the most persistent myth encountered by energy managers is: ‘fluorescent lights are best left on’. Many people know that fluorescent lamps use more energy when warming up than when they have settled down, but is that the whole story?

Fluorescent lamps use about twice as much energy when first turned on but this lasts for less than one second. So the additional energy needed to restart a fluorescent lamp is paid back after two seconds of the light being off.

Older style fluorescent lights with ferro-magnetic ballasts are cheaper to switch off whenever a room will be vacant for about five minutes or more with small variations according to the tariff and the difficulty and cost of re-lamping. This includes consideration of the reduction in life expectancy of about one hour that is incurred each time the fluorescent lamp is started. However, the modern fluorescent light with electronic ballast (including all T5 lights) normally start more gently (including pre-warming). Switching has no real effect on lamp life.

Implement and maintain automated control systems

Not all lights are required to be on at all times, particularly in industry and retail. Consider actual lighting requirements and which lights and lighting equipment should be switched on or off at each stage of the start-up and shut-down procedure.

Many modern buildings have lighting control systems that provide automation and programming of lighting according to time of day, daylight and occupancy. Where these are installed, checks should be made to ensure that lighting is off when it should be. For more information, see Utilise sensors and lighting controls.

Maintain lamps and fittings

Most lamps, especially mercury vapour, and to a lesser extent fluorescent lamps, produce less light with age but the lamps continue to draw the same power. Lamps, reflectors and diffusers also accumulate dirt reducing the useful light output. In some cases, the diminished light output leads people to install additional lights. A more energy efficient approach is to replace lamps when the light output declines noticeably and to clean lamps, reflectors and diffuser panels annually.

Fluorescent, compact fluorescent, mercury vapour and metal halide lamps all contain mercury which is toxic to humans and animals. To prevent the lamps entering landfills and the mercury entering the water table, these lamps should be disposed of through a collection scheme which recovers the mercury. There are commercial collection schemes for disposing of lamps. Some councils may also provide a lamp disposal service.

De-lamp and adjust the amount of light provided

The amount of light required in any area depends on the task being conducted. A hallway or walkway in an open plan office does not need as much light as nearby production areas, work stations or noticeboards. The recommended illuminance for the main types of visual task are listed in the Australian and New Zealand Standard 1680.2. It may be possible to reduce the number of fittings or lamps in an area which maintaining lighting at the level required.

Tip: When considering de-lamping, also investigate the condition of lamps and light fittings as replacement and/or cleaning may enable greater savings. Survey building areas and record what each area is used for and its current illuminance using a light meter. Ensure that the type of light used aligns with the task required.

Upgrade lighting systems

There are excellent opportunities for energy saving whenever upgrades or refurbishments are planned. Options for upgrading energy efficient lighting can be applied to all types of commercial, industrial and service facilities.

Some examples of opportunities in this area are outlined below.

Invest in more efficient lamps and luminaires

Lighting technologies such as compact fluorescent (CFL) and light emitting diodes (LED) offer 75–90% energy efficiency improvements on incandescent globes. Table 1 provides an overview of the typical energy efficiency improvements possible through investing in more efficient technologies.

Table 1: Efficient lighting retrofit opportunities

Replace lamp with
ExistingTypical savings Comments
Lamp typeFitting
Incandescent, tungsten halogen 25-100 WVariousCFL 5-25 W LED 2-20 W75-90%Lamp life will be extended, improving reliability and reducing maintenance costs.
Tungsten halogen (low voltage) 50 WDownlight or spotlightLED, CFL 7-10 W80-90%Not all lamps are compatible with existing transformers. LEDs and CFLs have longer and reduced heat output.
Mercury vapour 50 -100 WDownlightCFL 10-20 W50-80%Consider replacing fitting.
Mercury vapour, self-ballasted 120 WDecorativeCFL 24 W80%Lamp life will be improved.
Fluorescent T8 36 WVariousT5 kit20%Check power factor.
Fluorescent T5 28 WVariousT5 25 W10%Check ballast compatibility.

For more information

Use task lighting where appropriate

Task lighting provides the lighting level required for specific tasks—such as reading, inspection, displaying merchandise or art, walking, orientation, manual handling—without having to provide the same level of lighting to the surrounding areas. It can halve the energy requirements of area lighting.

Task lighting improves the working environment. This is, in part, because it gives individual workers the flexibility to control the location and direction of their lighting to suit their task and preferences. It also reduces uncomfortable levels of glare and high contrast. As some lights emit electrical noise, test the task light for interference with phones before committing to a particular model.

LEDs are particularly well-suited to task lighting, because the lighting produced is directional, they are physically small and are available with low light output and low power.

Tip: As task lighting may be a new concept to some people, consult with staff to discuss the benefits to them. It may be worth introducing task lighting gradually or on a test basis.

Modify existing fittings

Replacing whole light fittings sometimes is not practical or cost effective. Situations where modifying existing fittings could be preferable to replacement, include:

  • Expensive, bespoke or decorative light fittings
  • Fittings that are difficult to replace without modifying the building
  • Fittings that incorporate air conditioning supply or return-air openings.

In addition to energy savings, these modifications can yield additional benefits such as longer lamp life (see Table 2).

Table 2: Modifications to fittings that enable the use of more efficient lighting

Existing fittingModification to fittingTypical savings Comments
Lamp typeFitting
T8 fluorescent Any with standard ballastElectronic ballasts18%Remains a T8 fitting, longer lamp life.
Mercury vapourHigh bay or low bayElectronic ballast, metal halide ceramic>45%Longer lamp life, better colour rendition
 Metal halideHigh bay or low bayElectronic ballast, metal halide ceramic30%20% saving from lamp power reduction

Replace light fittings with more efficient systems

Replacing light fittings, as outlined in Table 3, can yield higher energy savings than modification because the replacement will produce the multiple benefits of a new fitting, including:

  • A fitting selected according to the required lighting level
  • More efficient, modern lamps (less energy, longer life)
  • Electronic ballast (lower energy consumption, longer lamp life)
  • More efficient fittings (reflector shape and reflectivity, diffuser efficiency, etc.)
  • Integrated sensors or controls (e.g. daylight dimming, movement detection).

Table 3: Replacement of fittings to enable more efficient lighting

Existing fittingReplacement fittingTypical savingsComments
Lamp typeFitting
Mercury vapour 400 WHigh bay or low bayMetal halide ceramic 250W and electronic ballast Light Output Ratio (LOR) >90%[1. Light Output Ratio (LOR) is the ratio of the total light ouput of the fitting to the output of the lamp(s) under stated conditions60%Will also improve colour rendering and stop flicker
Mercury vapour 400 WHigh bay or low bayHigh output fluorescent with integral control25%-80%Savings from lamp efficacy and inbuilt dimming and switching
Metal hallide 170-400 WHigh bay or low bayHigh output fluorescent with integral control20%-70%Savings from lamp efficacy, inbuilt dimming, switching
Fluorescent, T8VariousT5 fluorescent30%Savings from lamp ballast and fitting efficacy
Fluorescent, T8VariousT5 fluorescent with integral controls30%-80%Improved convenience
Tungsten halogenLinear, floodLED flood or spot80%-90%Much longer life (reliability and maintenance benefits) and less heat

Utilise sensors and lighting controls

Occupancy and daylight sensors can switch off lights automatically when they are not required. They are most effectively used in situations where there is low occupancy, long lighting hours and multiple lights on a single circuit. Savings of 80% have been measured in apartment building corridors. Some ideal applications are:

  • Shared spaces with low occupancy, such as staff lunch rooms
  • Areas that are daylit (e.g. maintenance workshops where lights are manually turned on around 7 am, but are rarely turned off as the daylight level increases)
  • Warehouses and storage areas that can be accessed at any time of the day, but are only visited infrequently.

Sensors and controls can be:

  • Installed at the same time as new lighting or retrofitted to existing lighting circuits
  • Stand-alone, controlling just one circuit
  • Part of a system incorporating communication among many sensors, controllers and lights; this permits flexible programming across several occupancy and daylight sensor locations
  • Purchased as light fixtures with integral sensors (daylight and/or occupancy). These fixtures allow users to achieve automatic lighting control by replacing just one fitting, being ideal for smaller areas.

Occupancy sensors for lighting control need to detect limited movements, sonics or heat signatures, such as those associated with somebody sitting in an office or standing at a machine. The main types of detection employed are:

  • Passive infra-red (PIR), which detect movement of a person who appears warmer than the surrounding, so detection might fail in a warm area (e.g. some manufacturing environments) or if people are wearing heavy winter clothes. PIR sensors require line-of-sight for detection, so will not work well where there are obstructions or blind corners (e.g. change rooms, storage areas).
  • Ultrasonic, which work on reflected ultrasound (beyond the range of human hearing) and the Doppler effect. This technology has the benefit of being able to detect an opening door, turning on lights just before somebody enters a room or corridor.
  • Acoustic, normally used in conjunction with another technology, where the acoustic sensor is used to keep lights on once the other sensor technology is triggered.

Some sensors combine several technologies (hybrid sensors) to improve detection accuracy.

Future developments

There are many innovations occurring in the areas of daylighting and ultra-efficient lighting technology. Innovations are bringing down the costs of low emissivity glass (which is already commercially available in Australia) opening up further daylighting options whilst minimising glare in commercial buildings.  Rapid developments and innovations in LED lighting have the potential to reduce energy use in the most efficient lighting by more than half.

Further detail on some of these innovations is outlined below.

Improving LED technology

LED efficiency was marginally better than that of incandescent lighting in 2007. In 2010, commercially available LED efficiency reached 50 lm/W (equalling compact fluorescent) and in 2011 it reached 90 lm/W, equalling linear fluorescent and metal halide lamps. LED manufacturers are reporting 200 lm/W in the laboratory which, if commercialised, would have the potential to more than halve the energy use of the most efficient existing fittings. LEDs offer large potential savings in applications such as outdoor and indoor signs, and exhibition lighting.

For more information

Electrodeless Induction Lamp and LEDs

The electrodeless metal halide induction lamp’s main advantages are long life and low maintenance costs. These lamps have mostly been applied where lamp replacement is difficult and expensive. The efficacy of induction lamps range from about 80 lm/W (100 hours) to 56 lm/W (60,000 hours). This is lower than the efficacy of some LEDs which are claiming equivalent lamp life and lower capital costs. If and when LEDs increase in power output and validate the predictions of lamp life, they can be expected to compete successfully with induction lamps.

Simulation and new building materials

Computer simulation helps designers provide daylighting without admitting direct sunlight. New glazing materials admit light while blocking infrared and ultraviolet light. Double glazed windows admit light while halving heat conduction, and various low emissivity coatings (‘low-e’ glass) can also help to manage radiant heat gain and re-radiation from the glass.

Other related innovations include light pipes, laser-cut panels that reflect light onto ceilings and aerogel panels that insulate whilst letting daylight through.

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