Rhythm & Blues

100 years ago, people spent 90% of their waking hours outdoors. Now we spend 90% of our time indoors. This means we are exposed to artificial light most of the time. Artificial light is different than sunlight. This has impacts on our well-being that most people don't realize.

The appearance of white light is expressed according to a Kelvin scale. The lower the Kelvin value, the warmer and more yellow the light; the higher the Kelvin value, the cooler and more blue the light. Common color temperatures for light bulbs range from 2,000 to 6,500 degrees Kelvin. These are soft whites with an amber hue at the low end of the scale. Above 5,000 degrees Kelvin the light has a brighter, bluish cast, which is good for alertness and seeing contrast between colors. These higher color temperatures are used in offices and warehouse facilities. (Note that these are variations in the characteristics of white light and are not related to other light colors or atmospheric temperature).

Natural light ranges from 2,700 to 6.500 degrees Kelvin, with the warmer color temperatures in the morning transitioning to higher temperatures at midday and then back to lower temperatures in the evening. This established pattern of natural light affects everyone. It's referred to as Circadian Rhythm. It controls the release of hormones such as insulin, glucagon, cortisol, and melatonin, This in turn affects your alertness, energy, mood, and sleep patterns.

Most light fixtures operate at one color temperature, so you can pick one that mimics natural light at a certain time of day, but it can't mimic the Circadian Rhythm pattern of sunlight. There are newer LED fixtures by Lutron (Ketra), DMF (Artafex), and others that can be automatically adjusted throughout the day to follow the pattern of natural light. These are referred to as Dynamic Tunable White Lighting, Circadian Lighting, or Human Centric Lighting. They come in a variety of form factors; tape lights, bulbs, track lights, and more.

If you are building a new home or doing a remodel, it would be a good idea to look into tunable lighting to see if it fits into your needs and budget.