Lighting

While individual light bulbs do not consume large amounts of electricity, the average Australian home contains 37 light bulbs. So choosing efficient and well-designed lighting can still save you energy and money.

Light bulb technology

Improvements in technology and minimum standards have raised the efficiency of lighting over the past decade.

In Australia, many incandescent light bulbs have been phased out. Mains voltage halogen light bulbs are being phased out where an equivalent LED (light-emitting diode) light bulb is available. Compact fluorescent light bulbs (CFLs) are being replaced in the market by even more efficient LED bulbs, which are increasing in popularity.

CFLs last more than 3 times as long as halogens, and LEDs can last more than twice as long as CFLs. LEDs also overcome some of the past criticisms of CFLs because they switch on instantly and don’t contain mercury.

Light bulbs are rated according to their brightness and their efficiency:

• Consumers used to purchase bulbs by the amount of power (or watts) they used; however modern bulbs – especially LEDs – produce the same amount of light using far less electricity. This means that it no longer makes sense to choose a new bulb based on how many watts it uses. Nowadays, the way to choose a new bulb is to look at how much light it produces, which is measured in ‘lumens’ (lm). A higher number of lumens means a brighter bulb. If a single light bulb were to be used to illuminate a room, standard bulb sizes in lumens are:
  • 420 lm – for a table lamp
  • 800 lm – for a small room
  • 930 lm – for a medium room
  • 1300 lm – for a large room or a bright work area
• Efficiency of a light bulb is measured in lumens per watt (lm/W). The higher the number, the more efficient the product. Lighting energy efficiency requirements are regulated through Minimum Energy Performance Standards for specific lighting products. Refer to the Energy Rating website for more information.

Lifetime costs

When choosing lighting, think about the lifetime costs. Although newer bulb technology generally costs more, these bulbs both last longer and use less electricity, thus lowering your energy bill. For example, the price of a halogen light bulb is often lower than the price of an equivalent LED light bulb. But an LED lasts 5 to 10 times longer and consumes one-fifth the energy. The lifetime cost for the LED is therefore much lower than for the halogen.

Savings will be largest in areas and rooms where lighting is on for extended periods (for example, light bulb use of 2–3 hours per day is typical for commonly used areas such as kitchens and lounge rooms.)

Aim to light your home to:

• provide a safe, comfortable, visually appealing and desirable environment
• be as energy-efficient as possible.

Design for light

Thoughtful lighting design combines strategies for daylighting – allowing natural light in through windows, skylights, etc. – and electric lighting to optimise the distribution of light inside the building. It considers:

• the best window sizes, glazing, and shading design for each orientation and room to reflect the expected solar angles, heat gain and glare
• what type of lighting (general lighting, background lighting, task lighting) would suit each room and activity
• the best position for lights to ensure good light distribution in a room.

Daylighting design aspects

The science of ‘daylighting’ aims to use daylight to reduce or eliminate the need for electric light inside a home. Sources of daylight include sunlight, which is an intensely bright, directional beam, and skylight, a diffuse light of about one-tenth the illumination of sunlight.

A goal of all new homes should be to maximise natural daylighting much as possible. Good daylighting design can reduce the amount of energy consumed by the building.

However, done incorrectly, daylighting can affect the building’s thermal performance. For example, direct sun through large windows, particularly in summer, can increase the heat or glare in a room. Occupants are likely to close the curtains or turn on the air-conditioner to reduce these effects which negates any energy-saving benefit that daylighting might have offered. Careful passive design can deliver both daylighting and good thermal performance.

Photo: Scott Dwyer

Windows

• North-facing windows introduce both sunlight and daylight into the home, particularly in winter when the sun is lower in the sky. Good design of eaves and other shading devices can ensure the direct sun can enter to help heat the home in winter, but be blocked in summer.
• South-facing windows provide daylight without the heat gains of direct sunlight — making them an ideal orientation for houses in warmer climates where home cooling is the main imperative.
• Clerestories (with the associated adjustable shading or appropriately sized eaves) are very effective at delivering daylight to the core areas of a home. High-level windows will diffuse light further into a room than lower-level windows
• Large areas of glazing are not necessary to provide ample daylight all year round. For rooms that have only one external wall, 2 smaller windows spaced apart will reflect more light from side walls than 1 central window, as well as provide more ventilation options.

Photo: Alan Pears

Interior design

• Light-coloured interior surfaces reflect more light and reduce the level of artificial lighting required. Light is heavily absorbed (wasted) in dark-coloured rooms.
• Light can be indirectly reflected to create subtle background illumination, but only with light-coloured rooms or surfaces. Internal surfaces of indirect lighting should be white or reflective, to minimise absorption of potentially useful light.
• To light task areas effectively, direct natural lighting from windows, skylights etc must be close to the task area. Windows should be part of the perimeter wall of the room being lit, while skylights with diffusers should be located in the roof directly above the task area to be lit.
• However, direct sun should be excluded from task areas (particularly polished surfaces including kitchen benches and desktops) because of the high potential for glare and discomfort.

Lighting design products

• Skylights and tubular daylighting devices of appropriate sizing and design can let in light without adding significant heat in summer or losing much warmth in winter.
  
  Light tubes can bring natural light into the home, replacing electric lighting in poorly lit spaces or rooms

   

• Glass bricks are a useful source of daylight in walls that are close to boundaries or need privacy. They can let in diffuse daylight while maintaining sound and visual privacy in walls that are close to boundaries or face the street.
• Light shelves are horizontal overhangs with a reflective surface that are designed to reflect daylight deeper into a space. By varying the height, angle, and internal or external projection of a light shelf, you can control the pattern, intensity and depth of penetration of natural light (including sunlight) within a space. Light shelves are suitable for north and south elevations, but are less effective for the varying sun angles of east and west. Exterior shelves generally provide more effective shade while interior shelves provide deeper reflected light. A combination of exterior and interior shelves works best to give an even illumination gradient.
  

  

  Light shelves reflect light deeper into rooms

   

• LED virtual skylights (also known as solar skylights, solar LED lights, skylight alternatives, or imitation daylighting devices) provide artificial light from LEDs that are powered by solar energy. While they do not provide natural light, they can bring the effect of daylight to a dark room or space where the installation of a skylight is restricted, or where there are concerns about the risk of roof leaks or hail damage. The system involves an LED light mounted on (or in) a ceiling in the home, connected to a dedicated roof-mounted solar collector. Because it relies on solar power, the light dims according to the time of day and with passing cloud cover, simulating conditions outside. The LED light fittings come in various shapes and sizes and a single solar panel can power multiple lights. LED virtual skylights require little or no roof space and installation is less costly than a conventional skylight.
  

  

  Photo: illume Skylights Pty Ltd

Photo: illume Skylights Pty Ltd

Electric lighting design aspects

Use of electric lighting in the home usually meets 2 needs: lighting a room or space at night, or lighting a specific task or feature. Matching the light fitting and light bulb to each purpose will maximise your lighting and reduce energy use.

Plan your lighting to complement your lifestyle. Consider the activities that occur in each room, the atmosphere you want to create and the decorative elements you want to highlight.

Consider in particular the areas that serve more than one purpose and require more than one style of lighting (for example, relaxed entertaining, media viewing, reading, general activity). Use separate lighting solutions and circuits for each function rather than integrating them into a single circuit. Lights may need to be on separate switches, or dimmers used to create the lighting desired.

General or ambient lighting

Ambient lighting provides overall, general lighting that radiates a comfortable level of brightness. The eyes adapt to low light levels at night and it is unnecessary to try to duplicate the high level of illumination available from daylight. A central source of ambient light in all rooms is fundamental to a good lighting plan:

• Use omni-directional (light in all directions) light bulbs in pendants, chandeliers, ceiling or wall-mounted fixtures.
• Choose light fittings and lamp shades that allow most of the light through so a lower lumen light bulb can be used. Some light fittings can block or absorb 50% or more of light.
• Avoid using downlights for general illumination. They can make bright ‘pools’ of light on the floor while making the ceiling cavity appear dark which creates a ‘gloomy’ ambience. Downlights are better suited to task lighting over workspaces. Up to 6 downlights may be needed to light the same area as 1 pendant light.

Photo: Getty Images

Task or accent lighting

Task lighting is used to illuminate specific tasks such as reading, sewing, cooking, homework, games, or hobbies. Accent lighting is used to create visual interest in a room by providing mood setting (for example, table lamp on side table in lounge room) or drawing attention to key objects or spaces (for example, artwork on the wall).

Downlights, reading lamps, or table lamps are an effective, flexible, and efficient means of providing task or accent lighting rather than increasing general lighting of the entire space:

• Use desk, table, or floor lamps in areas where the activity or furniture is likely to change positions (lounge, dining, bedrooms).
• Where illuminated task surfaces will not change (for example, over kitchen benches), use fixed directional lighting such as directional light bulbs or downlights. The following are key points for selecting the appropriate beam angle for directional light bulbs:
  • Beam angle is the angle at which light intensity drops to 50% of centre beam intensity. Virtually all (around 90%) light from a directional light bulb is in the beam and very little light reaches other surfaces outside the path of the beam.
  • Basic rule: for the same lumens of light bulb, the smaller the beam angle the brighter the surface illuminated, but the smaller the area illuminated.
  • Select the appropriate beam angle by determining the largest dimension of the feature to be lit and the distance from it. The packaging of most directional light bulbs generally shows a simple graphic to help select the appropriate beam angle.
• Make sure task lighting is free of distracting glare and shadows, but bright enough to prevent eye strain.

Choosing lighting products

There is no ‘best’ lighting product for all applications. Each light type has advantages and disadvantages and good design uses an appropriate type for each application.

Types of bulbs

The various light bulb technologies generate light differently. Choose light bulbs best suited to producing desired lighting effects such as light distribution, switch-on time and dimmability. For example, some CFLs take a few seconds to strike and ‘warm up’, and are thus unsuitable where lights are switched on and off quickly (for example, kitchen pantry). Not all LEDs can be dimmed, so check they are dimmable LED bulbs or use an LED compatible dimmer. If you are installing a new LED lighting system with dimmers, look for an LED and dimmer combination that claims to be compatible. If you are installing LEDs into an existing system with dimmers already installed, it is recommended that you trial 1 or 2 dimmable LEDs first to check for compatibility. If you experience difficulties it is recommended you engage an electrician to assist with either finding light bulbs compatible with your dimmer, or to identify the correct dimmer model to find compatible lights.

The following table gives a summary of the different bulb options available for nondirectional (room) lighting or directional (task) lighting.

Nondirectional light bulbs

* The actual life of light bulbs can vary depending on the manufacture (check the review by Choice before buying).

Directional light bulbs

* The actual life of light bulbs can vary depending on the manufacture (check the review by Choice before buying).

Integrated LED luminaires

In addition to LED light bulbs, LED lighting is also supplied as integrated luminaires, where the LED light source is combined with the light fitting. These can be an alternative to directional, non-directional and linear fluorescent lighting, and can simplify installation and provide a consistent aesthetic. As with light bulbs, consider the specifications of the product such as lumens, efficacy, colour temperature, colour rendering, dimmability, and beam angle.

In many cases the actual LED light source within the integrated luminaire will not be replaceable by an unqualified person, potentially requiring the entire light fitting to be replaced if the product fails. If the integrated luminaire is directly wired to the mains supply without a socket, you will also need to engage an electrician. Thus the lifetime of the product becomes more important, and if you are fitting out your house for a consistent style, you may wish to buy 1 or 2 spares as the same model may no longer be available later on.

Colour of light

Different wavelengths of light are perceived as different colours by the human eye. ‘White’ light contains all the wavelengths of light at equal strength and thus appears colourless.

Although light bulbs theoretically emit something close to white light, they emit different combinations and strengths of light wavelengths. This mean that the light they emit is not completely colourless.

Source: www.rs-online.com/designspark/led-wavelength-vs-led-colour

Two ratings are used to describe the colour of white light sources:

• correlated colour temperature (CCT)
• colour-rendering index (CRI).

Correlated colour temperature

CCT, measured on the kelvin (K) temperature scale, describes the ‘shade’ of white light emitted.

Lighting with ‘daylight’ colour temperatures should be avoided for night-time use (for example, nightlights) as it may disrupt the body’s circadian rhythms that regulate sleep cycles. For more information on designing lighting to support healthy circadian rhythms see the WELL Standard.

Common colour temperatures and their typical uses

Colour-rendering index

CRI rates the ability of the light to accurately portray colours of objects in the space being lit. The CRI is a scale between 0 and 100, where 100 represents true natural colour reproduction for that particular colour temperature.

Sunlight is defined as having a CRI of 100. A CRI of higher than 80 is usually adequate, but for specialised tasks where colour is important (food preparation, applying makeup, painting), it is advisable to choose light bulbs with a CRI above 90. The CRI of typical residential light bulbs are:

• incandescent light bulbs – 100
• fluorescent, CFL light bulbs – 80–95
• LED light bulbs – 80–90+.

Light bulbs of the same colour temperature (CCT) can vary in their ability to render colours correctly (CRI). No matter what colour temperature light you choose, if it has a low colour-rendering index then nothing will look good under it.

Installing lighting

Lighting installations in new homes must comply with the requirements of the National Construction Code (NCC). Important safety aspects of electric lighting are also covered by Australian Standards.

National Construction Code

The NCC includes guidance on:

• minimum requirements for artificial lighting
• heat gains and losses from reduced coverage of ceiling insulation due to downlight and skylight installations
• external glazing performance and shading
• access to daylight through windows.

In Australia, any new home or significant renovation of an existing home must provide adequate natural light to all habitable rooms and artificial light in bathrooms, airlocks and laundries where natural light is not available. Concessions to these rules may exist for certain lighting depending on their application and your state or territory. Refer to NCC 2022 Volume 2 (Part H4), the ABCB Housing Provisions (Part 10.5 and 13.7.6) and AS/NZNZS 1680 for more information.  

To minimise heat gains and losses in homes, ceiling insulation should form a continuous thermal barrier between the interior spaces of the house and the exterior. Each skylight and recessed light fitting, such as a downlight, introduced into the ceiling space creates a ‘hole’ in the insulation barrier and potentially creates a path for conditioned air to leak from the house. The high operating temperatures of many light bulbs also demand a fire safety requirement for an additional space between each light fitting and the edge of the insulation to prevent risk of fire (Australian Standard AS/NZS3000:2007 Electrical installations).

Thermal losses through these breaks in a home’s insulation will ultimately increase a household’s energy bills for its heating and cooling. You may be required to account for these losses by increasing the thermal resistance of the chosen insulation material to demonstrate NCC compliance, depending on the percentage of ceiling area that is uninsulated

Some current LED lights cannot be covered with insulation, but can be used in combination with a fire safety barrier tested and classified in compliance with Australian Standard AS/NZS 5110, Recessed lighting barrier. Insulation contact (IC) rated LED downlights are becoming available. IC rating is a measure used to determine if a recessed downlight is suitable to come into contact with your building insulation or not. Essentially, an IC-rated downlight can be abutted and directly covered with insulation. This makes the installation process easier as the insulation can be laid unbroken over the whole ceiling area and reduces the fire risk.

Take note of manufacturer’s installation instructions for lights that include warnings about covering them with insulation, or display a symbol meaning ‘Do not cover’. Always employ a qualified electrician to install lighting. For more information about electrical safety requirements, refer to Insulation.

Lighting controls

Switches and controls

Time of use, hours of use, occupancy, and traffic through spaces vary in the home. Switches and controls can be a very effective method of providing lighting only when and where it is required.

Some basic principles:

• Provide multiple switches to control different lighting elements (ambient, accent or task) in a room where not all may be required all the time. One switch to turn on all lights in a large room is very inefficient. When choosing switching groups, always begin with lighting that is needed most, such as that over the kitchen benches, then work backward.
• Place switches at exits from rooms and use 2-way switching (for long hallways or stairwells) to encourage lights to be turned off when leaving the space.
• Timers and sensors can be useful in rooms used infrequently where lights may be left on (for very long times) by mistake, or for children, the elderly, and people with disabilities. Built-in daylight sensors make sure the light does not turn on unnecessarily during daylight hours. Refer to Smart lighting below for more information.
• 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 particular light bulb types, so seek advice.
• Consider using solar powered lighting (with rechargeable batteries) for garden and sensor security lights.
• Modern dimmer controls save energy and increase light bulb life. However, there is a difference depending on the type of light bulb. For halogen light bulbs, reducing light output to 50% saves only about 25% of the energy. For LEDs, the effect of dimming is linear so reducing light output by 50% saves half the energy. As mentioned previously, not all LEDs can be dimmed, leading to flicker in some instances. For lights you dim most of the time, consider replacing them with light bulbs of lower lumens.

Source: https://cnsensorlight.en

Smart lighting

Lights that can be dimmed, change colour, are automated, or controlled remotely over a network by a device such as a tablet or smart phone can be referred to as ‘smart lighting’. As with other smart home devices, smart lighting requires a reliable wi-fi network and a control device to operate them.

Smart lighting comes in a wide variety of forms and fittings, with many different types of product available. Check that the smart lighting products you choose are compatible with the control devices and wi-fi router you are using (refer to Connected home for more information). Multiple lights can be connected and controlled (usually via an app but sensors are also available). Smart lighting can be integrated with other smart home devices.

Most smart lighting light bulbs need to be left in standby mode to remain controllable, so they will consume electricity even when they appear switched off when using an app or remote. This can reduce your energy savings. Depending on the amount of standby electricity used (which can vary by product); in worst cases, in terms of total energy use, the smart LED light bulb may be little more efficient than an incandescent light bulb. Checking the smart LED’s standby electricity usage before buying can help reduce this cost – look for 0.5W or less. In order to save the most energy, it is best to turn lighting off at the wall switch. However, this may limit some of the features of having a smart light by requiring manual switching on and off.

Disposing of light bulbs

How best to dispose of your light bulb when it reaches its end of life depends on its type. CFLs contain mercury so these need to be recycled through local government or community programs.

For information on programs in your state and local area, check with your local government and at FlouroCycle, or Recycling Near You.

Incandescent, halogen, and LED lamps do not contain toxic materials, but may be able to be collected as part of the same programs for CFLs. Otherwise, they are generally regarded as being safe to wrap in paper and disposed of with other general household garbage.

• Department of Agriculture, Water and the Environment, Disposal of mercury-containing lamps.
• DIS (Department of Industry and Science) (2015). Residential energy baseline study: Australia, DIS, Canberra.
• Department of Climate Change, Energy, the Environment and Water, Households. 
• Energy Rating, Choose a lightbulb: the Light Bulb Saver App, video [Youtube].
• Energy Rating, Light Bulb Saver app.
• Energy Rating (2012). Residential Energy Monitoring Program collection and analysis of end-use metering data for lighting.
• Energy Rating (2016). Fact sheet: a consumer’s guide to buying quality LEDs.
• Energy Rating (2016). Fact sheet: light bulb buyers guide.
• Greenhouse and Energy Minimum Standards Regulator, Energy rating database. 
• Illuminating and Engineering Society of Australia and New Zealand.
• Lighting Council Australia.
• Recycling Near You, Light globes.

Learn more

• Find out about Orientation to maximise the opportunities for introducing daylight to rooms where you need it most
• Explore Glazing and Shading to find your best window options for introducing daylight while minimising heat and glare  
• Read Appliances and technology to find other ways to save energy in your home

Authors

Original author: Geoff Milne

Contributing author: Chris Riedy

Updated: Steve Coyne 2013, Scott Dwyer 2020, Department of Climate Change, Energy, the Environment and Water 2023