Difference between LED color temperature

The difference between LED color temperatures is one of the most important things to know when installing a new light fixture for a home or business. Let's get the biggest point out first -- lamps running the same wattage and outputting the same lumen number can look very different, depending on their color temperature. This difference can extend to biology because our brains are configured to respond to certain colors of light in profound ways. For example, if the wrong fixture is placed in the bedroom, it can keep someone up all night, even if they want to sleep. The same applies to lighting artwork, cabinet lighting and even embedded general lighting applications.

Obviously, color temperature makes a big difference. LED color temperature diagram

So, what is color temperature?

First, define what color temperature is. Although there is a long history behind the term, including experiments by physicists in the 18th century, there is a simple way to express it.

Imagine a piece of ferrous metal. Size or shape doesn't matter. For convenience, consider the metal filament inside the bulb. When this black filament is heated, it glows, and as the temperature increases, it begins to glow red, orange, yellow, white, and finally blue at extremely high temperatures. When lighting professionals refer to color temperature, they are really referring to the color of the black metal that glows at a given temperature, in Kelvin.

Here's a quick look at where these color temperatures are on the scale:

1700K - The dim glow of a match flame

1900K - Steady light of candle

2700K -- Warm incandescent light fixture

3000K - The sun at sunset or sunrise

3500K -- Bright white, most fluorescent lamp Settings

5500K - Daylight on a clear day

6500K - Daylight on cloudy days, which is also the setting for most computer monitors

7500K - The coolest setting for most fluorescent lamps

The lower the color temperature, the warmer or redder the light will appear. The higher the temperature, the colder the light will appear, or the bluer it will appear.

In residential and commercial lighting field, almost all lamps will fall between 2000K and 6000K. Perhaps the two most common color temperatures are 2700K and 3500K, as warm lamps dominate residential environments. But cool fixtures also have their uses, mostly in commercial and industrial areas. The reasons are aesthetic and biological.

Warm or cool?

There is not much debate about what fixtures should be used where. In general, warmer fixtures are preferred in most residential environments, and most homeowners prefer them. Cooler fixtures work better in commercial and industrial environments, where workers tend to prefer them. But why are warm installations better suited for residential installations and cool ones better suited for commercial environments? This is where biology comes into play.

In the presence of bright white and cool light fixtures, the body releases serotonin, a neurotransmitter that normally makes people feel more alert. This response is why sunlight can make people feel more awake and active, and why it's hard to fall asleep after staring at a computer monitor for a while. When those blue or white tones are absent, the body releases melatonin, a hormone that helps regulate circadian rhythms (the body's natural sleep-waking rhythms) and promotes sleepiness. At night and at sunset, the absence of blue and bright white light puts the body into a lethargic state.

There are some obvious color temperature applications that can be derived from biology. Incandescent or warm-color LEDS promote the release of melatonin, while fluorescent or cold-color LEDS promote the release of serotonin.

This is why warm fixtures are reserved for most residential applications such as bedrooms or living rooms. In these environments, warm light helps people relax and unwind to fall asleep. The only places where white or cold light is usually preferred are the kitchen and bathroom. Here, people seek the higher contrast and better color rendering provided by neutral and cool lamps. Some homeowners install cool devices in their bedrooms for reading because the cool devices contrast sharply with the paper used in books. Some homeowners even prefer to use cooler LED fixtures for general bedroom lighting because it can help them wake up in the morning.

In some business environments, especially lobbies and reception areas, as well as businesses such as restaurants and hotels, warm installations are still preferred. In general, any business that needs to make customers feel comfortable will need warm fixtures in certain areas.

However, cooler fixtures are needed in any environment where productivity and high contrast are required. The biggest use of cold leds is in office buildings, where more blue light can help improve worker productivity.

A 2016 study published by the American Academy of Sleep Medicine confirmed this. In the study, researchers exposed test subjects to bright blue light for 30 minutes and then had them take cognitive tests. Researchers found that people exposed to blue light had faster reaction times and scored higher on knowledge tests. In short, blue light is a brain booster. Its effects last nearly an hour after exposure, so the right fixtures in an office building can amplify performance across the board.

Blue and bright white lights are almost always the norm for industrial properties such as warehouses and manufacturing facilities. Part of the reason is that workers in these facilities need to be on constant alert. Another reason is that white light is best for contrast between colors, and because it shows colors better than warm-colored lamps. This is not just for productivity or aesthetic reasons. It could also be a security issue. Warning signs and safety gear are usually orange, making it harder to tell under warm fixtures. With bright white fixtures, it's easier to see another worker wearing an orange safety vest, or a sign warning that there's a worker nearby.

In the end, the owner has the final say on what color temperature to choose. The answer will vary, depending on what mood the fixture needs to evoke and what purpose it serves. And there is no need to choose one color temperature for the entire property. Warm lamps can be installed in one room, while cool lamps can be installed in another room.