Lighting that emits too much light or shines when and where it’s not needed is wasteful. Wasting energy has huge economic and environmental consequences.
In an average year in the U.S. alone, outdoor lighting uses about 120 terawatt-hours of energy, mostly to illuminate streets and parking lots. That’s enough energy to meet New York City’s total electricity needs for two years! We estimate that at least 30 percent of all outdoor lighting in the U.S. alone is wasted, mostly by lights that aren’t shielded. That adds up to £3 billion and the release of 21 million tons of carbon dioxide per year! To offset all that carbon dioxide, we’d have to plant 875 million trees annually.
Environmental responsibility requires energy efficiency and conservation
- Installing quality outdoor lighting could cut energy use by 60–70 percent, save billions of £££ and cut carbon emissions.
- Outdoor lighting should be fully shielded and direct light down where it is needed, not shining up into the sky.
- Unnecessary indoor lighting – particularly in empty office buildings at night – should be turned off.
New lighting technologies can help conserve energy
- LEDs and compact fluorescents (CFLs) can help reduce energy use and protect the environment, but only warm-white bulbs should be used. Learn more about LEDs and colour temperature from our LED Practical Guide.
- Dimmers, motion sensors and timers can help to reduce average illumination levels and save even more energy.
Quality lighting design reduces energy use and therefore energy dependence. It also reduces carbon emissions, saves money and allows us to enjoy the night sky. Watch a clip of the documentary The City Dark to learn how lighting design can reduce light pollution and also conserve energy.