Five Principles For Responsible Outdoor Lighting
Light pollution disrupts wildlife, impacts human health, wastes money and energy, contributes to climate change and blocks our view of the universe.
Photo©pavelshlykov/123rf
Too often, outdoor electric lighting installations at night are over lit, are left on when not needed, and are harmful to the environment. As a result, light pollution is a growing global issue that can negatively affect our environment as well as our quality of life. By joining forces, our shared goal is to prevent and reduce light pollution through the proper application of quality outdoor electric lighting.
Responsible outdoor lighting is:
1. USEFUL — All light should have a clear purpose.
Light is useful for safe wayfinding and to help perform specific tasks. Before installing or replacing a light, determine whether light is needed. Consider how the use of light will impact the area, including wildlife and the environment. Consider using reflective paints or self-luminous markers for signs, curbs, and steps to reduce the need for permanently installed outdoor lighting. If you find that lights on your property are not necessary or useful, remove or disable them so they are not accidentally turned on.
2. TARGETED — Light should be directed only to where it’s needed.
Use shielding and careful aiming to target the direction of the light beam so that it points downward. Target your fixtures so that light does not spill beyond where it is needed. Be especially mindful of light that spills up into the sky, or onto other people’s property. The light source should not be visible from beyond your property.
3. LOW LEVEL — Illumination should be no higher than necessary.
Is the amount of light appropriate for the intended task? Use the lowest light level required. Light levels are measured in lumens, so check your light source and use the lowest lumens possible. Excessive light can contribute to glare, actually making it harder to see things well. If you find that the lighting level around your home is too bright for the task it is intended for, consider changing the fixture’s bulb or installing a new fixture with a lower lumens value. Be mindful of surface conditions, as some surfaces may reflect more light into the night sky than was intended.
4. CONTROLLED — Light should be connected to active controls.
Use controls such as timers or motion detectors to ensure that light is available when it is needed, dimmed when possible, and turned off when not needed. Motion sensors should be set to times of 5 minutes or less. Dusk-to-dawn sensors are strongly discouraged as they release light when it is not needed.
5. WARM-COLORED — Use warmer-color lights where possible.
Limit the amount of shorter wavelength (blue-violet) light to the least amount needed. Most light bulbs manufactured today have a Kelvin rating printed on the bulb. Low Kelvin ratings (3000 Kelvin or less) are considered warm and generally emit less harmful blue light than high Kelvin. For home lighting, there are good options at 2700 Kelvin or less.
By applying these principles, properly designed electric lighting at night can be beautiful, healthy, and functional. Projects that incorporate these principles, whether a residential home, a development, community, or region, will save energy and money, reduce light pollution, and minimize wildlife disruption.
The International Dark-Sky Association has worked to protect the night from light pollution since 1988. Its impact now reaches 51 countries, with members, advocates, and dark sky places in North America, East Asia, Europe, Latin America and the Caribbean, the Middle East, Africa, Oceania, and South Asia. Find out more or get involved at DarkSky.org.
