LED streetlights are great for the environment. They consume much less energy than standard high-intensity discharge (HID) lights, last three times longer, and they reduce greenhouse gas emissions and maintenance costs. In general, LED lights also contribute less to light trespass because they emit direct illumination. Because of all their great qualities, many cities have started to convert from HID to LED streetlights. What some cities have failed to consider, however, is that while LED streetlights are capable of emitting different colors of light, not every color should be used in public outdoor spaces. Bright blue-rich white light can cause some issues for residents, local wildlife, and night sky visibility. When it comes to streetlights, the warmer the color/correlated color temperature (CCT) the better.
CCT will tell you what hue and tone of white to expect from a specific streetlight. It is measured in Kelvin (K), which is similar to degrees in Celsius. Different temperatures on the Kelvin scale represent different colors. For example, light at 2000K-3500K looks more orange/yellow and is called ultra warm or warm white, and as temperature increases in Kelvin, color changes to more of a “paper white” known as natural or neutral white (between 3500K and 5100K) and finally into a bluish-white known as cool white (5100K-20000K).
The International Dark-Sky Association (IDA), a group whose purpose is to protect the night sky, recommends that LED street lights have a CCT of 3000K or less. These street lights will have a warm white glow that is safer for people and wildlife. The CCT of daylight is right around 6500K, which appears pretty blue. Introducing that type of light into people’s homes through their windows at night can suppress melatonin production and disrupt circadian rhythm. Melatonin doesn’t just help us fall asleep; it has antioxidant properties, boosts the immune system, and regulates certain hormones. There have been studies showing that it can even aid in IBS as well as migraine and cancer prevention.
Throughout the day, light changes from a warm white color at dawn to natural white then to a cool white in the afternoon, back to natural white, and eventually to an ultra warm white color at sunset. Our bodies are used to this cycle of light. Artificial lights that deviate from the natural lighting cycle can throw off our circadian rhythms. The National Institute of General Medical Sciences states that, “Circadian rhythms are physical, mental and behavioral changes that follow a roughly 24-hour cycle, responding primarily to light and darkness in an organism’s environment.”
In addition to the possible effects on health, cool white street lights can increase disability glare. Disability glare happens when stray light enters the eye and affects your ability to see distances and space correctly. According to the report, this happens “. . . because blue light scatters more within the human eye.” While it’s not directly causing harm to someone’s health, glare decreases driver safety and can lead to traffic accidents.
At night, blue light used outdoors can also wreak havoc on ecology. Introducing light with a CCT that’s close to daylight essentially changes the daily cycle that plants and animals are used to. They depend on this cycle of light and dark for hunting, reproduction, sleeping, migrating, and protection. Nocturnal animals have suffered greatly from cool white light at night; the IDA reports that, according to research scientist Christopher Kyba, “. . . the introduction of artificial light probably represents the most drastic change human beings have made to their environment.” Insect populations are declining because they are attracted to the cool white light. They circle under it until the point of exhaustion and death. Plants, birds, and other animals need insects to survive, so this fact alone greatly affects our ecosystem.
When you purchase LED street lights from bbier lighting, you will benefit from close to zero maintenance cost for at least 10 years. The reason why you would not need to spend much money on maintenance of LED street lights is that they are highly durable. If you get solar LED lights, the power consumption and electricity costs would be reduced further.