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Designing homes to conserve energy and use it efficiently, from sources that cause least environmental harm.
Appropriate lighting levels
Appropriate lighting levels are important for safety, comfort and energy efficiency.
On this page:
- Required and recommended lighting levels
- Types of lighting
- Outdoor lighting
The level of light on a surface is called illuminance. It is expressed as lumens per square metre or lux. In determining the appropriate amount of lighting, consider:
- the passive design daylighting provided by the design of the building
- direct lighting from lamps
- reflected light – levels will be higher from lighter-coloured or glossier surfaces.
Good lighting design is said to be lighting that ‘allows you to see what you need to see quickly and easily and does not cause visual discomfort but does raise the human spirit’.
Insufficient light levels can be uncomfortable and unsafe. Too much light can cause glare, which is also uncomfortable and can cause headaches or eyestrain, and too much artificial lighting wastes energy.
Required and recommended lighting levels
New Zealand Building Code clause G7 Natural light requires 30 lux of natural light at floor level for 75% of the year. Clause G8 Artificial light requires 20 lux of natural or artificial light at floor level at all times when the room is inhabited. Though energy efficiency can be maximised by providing no more than the minimum level of lighting required, this may not always be safe or comfortable.
Recommended lighting levels are:
- 150–200 lux for general household activity – for example, vacuuming or washing
- 300–500 lux for focused activity – for example, reading or studying, working on a car
- 800-1000 lux or more for concentrated activity – for example, fine detail sewing.
Adjustments should be made to these recommended lux levels so they are:
- higher – if there isn’t much reflected light, or levels of light and dark contrast are low, or the area has no windows, or the occupants are older people
- lower – if the task is of short duration.
Types of lighting
Generally, lighting within a home can be broken into:
- general lighting to provide an all-over low-level illumination of a space
- task lighting to illuminate an area (desk or benchtop) where a higher lighting level is required – task lighting is more effective where lower wattage lights with a focused light beam are specified, and task lighting can create issues of glare, flicker, noise or heat output
- accent lighting to highlight decorative or dramatic features using spotlights or wall washer lights.
Outdoor lighting may be necessary for safe progress along pathways or steps leading to the front door after dark. Outdoor lighting may also help occupants make the most of outdoor areas such as decks.
Excessive outdoor lighting can be a nuisance to neighbours, however, and may result in light pollution. This can have negative effects on health and the environment and can be a waste of energy. You can get more information from the International Dark Sky Association.
Updated: 24 May 2021