The difference between LED color temperatures is one of the most important things to know when installing new fixtures for a home or business. Let’s get the biggest point out of the way first – lights that run the same wattage and output the same lumen count can look wildly different depending on their color temperatures. And this difference can extend to the biological level, as our brains are configured to respond to certain colors of light in profound ways. If the wrong fixtures are placed in the bedroom, for instance, it can keep someone up late into the night, even when they want to sleep.
Clearly, color temperature makes a big impact.
So, exactly what is color temperature?
First, a definition of what color temperature is. Although there is a lengthy history behind the term, involving experiments by 18th-century physicists, there’s a simple way to put it.
Imagine a piece of black metal, the size or shape is unimportant. To make it easy, consider a metal filament inside a light bulb. As this black filament is heated, it glows, and as it increases in temperature, it begins glowing red, to orange, to yellow, to white and then finally blue at extremely high temperatures. When a lighting professional refers to color temperature, they are really referring to the color this piece of black metal glows at a given temperature (measured in Kelvin).
Here’s a quick look at where these color temperatures fall on the scale:
- 1700K – the dull glow of a match flame
- 1900K – the steady light of a candle
- 2700K – warm, incandescent fixtures
- 3000K – the sun at sunset or sunrise
- 3500K – bright white, the setting for most fluorescent fixtures
- 5500K – daylight during a sunny day
- 6500K – daylight during a cloudy day, also the setting for most computer monitors
- 7500K – the coolest setting for most fluorescent lights
The lower the color temperature, the warmer the light will appear, or the redder it will appear. The higher the temperature, the cooler the light will appear, or the bluer it will look.
In the residential and commercial lighting world, almost all fixtures will land somewhere between 2000K and 6000K. Perhaps the two most common color temperatures are 2700K and 3500K, as warm fixtures dominate residential settings. But cool fixtures have their purpose as well, and primarily in the commercial and industrial spheres. The reasons for this are aesthetic and biological in nature.
Warm or cool?
There isn’t too much controversy over what fixture should be used where. In general, warmer fixtures are preferred in most residential settings, and most homeowners prefer them. In commercial and industrial settings, cooler fixtures work better, and workers tend to prefer them in this setting. But why are warm fixtures better for residential installations, and cooler fixtures for commercial environments? This is where biology plays an important role.
In the presence of bright white and cool fixtures, the body releases serotonin, a neurotransmitter that usually makes people feel more alert. This response is why sunlight can make someone feel more awake and active, and why it’s hard to fall asleep after staring into a computer monitor for a while. When those blue or white hues are absent, the body releases melatonin, a hormone that helps configure the circadian rhythm (the natural wake-sleep rhythm of the body) and encourages sleepiness. At night and at sunset, blue and bright white light are absent, sending the body into a sleepy state.
There are some obvious applications of color temperature that can be derived from biology. Incandescent lights or warm LED lights encourage the release of melatonin, while fluorescent or cooler LED lights encourage the release of serotonin.
That’s why warmer fixtures are reserved for most residential applications, like the bedroom or living room. In these settings, the warm light helps people relax and wind down for sleep. The only places where white or cooler lights are typically preferred are in the kitchen and bathroom. Here, people look for the higher contrast and better color rendering that neutral and cool fixtures offer. Some homeowners install cooler fixtures in their bedrooms to read by, as cool fixtures contrast well with the paper used in books. A few homeowners even prefer cooler LED fixtures for general bedroom lighting, as it helps them wake up in the morning.
Warm fixtures are still preferred in some commercial settings, particularly lobby and reception areas, and for businesses like restaurants and hotels. In general, any business that needs to make its customers feel comfortable will need warm fixtures in some areas.
However, cooler fixtures are needed in any setting where productivity and high contrast are needed. The single biggest application of cool LEDs is in office buildings, where bluer light can help boost worker productivity.
A 2016 study published by The American Academy of Sleep Medicine confirms this. In that study, researchers exposed test subjects to 30 minutes of bright blue light, and then had them engage in cognitive testing. What researchers found was that those exposed to the blue light displayed faster reaction times and better scores on knowledge tests. In short, blue light is a brain booster. And its effects last nearly an hour following exposure, so the right fixture in an office building can magnify performance across the board.
Blue and bright white light is almost always the standard in industrial properties like warehouses and manufacturing facilities. This is partly because workers in these facilities need to remain alert at all times. Another reason is because white light is the best at creating contrast between colors, and because it renders color better than warm fixtures. This isn’t just for productivity or aesthetic reasons. It may also be a safety issue. Warning signage and safety gear is usually colored orange, and under warm fixtures, it’s harder to pick this out. With bright white fixtures, it’s much easier to see another worker in an orange safety vest, or signage warning about work crews nearby.
It Comes Down to Choice
In the end, property owners have the final say regarding what color temperature to settle on. The answer will be different, depending on what mood the fixtures need to evoke, and what purpose the fixtures are intended for. And there’s no need to just pick one color temperature for an entire property. Warm fixtures can be installed in one room, and cool fixtures in another.
And with emerging lighting technologies like LEDs, energy efficient options are available throughout the spectrum. All a home or business owner needs is a plan to get the configuration they want, and an experienced lighting firm can assist with that as well.