September 11, 2017

How to Buy Human-Centric Light

Professional lighting companies need to value the benefits of daylighting, and explore daylight options with their customers, if they want to legitimately represent themselves as authorities in human-centric, circadian or tunable-white light. Understanding daylighting is the prerequisite to fully grasp the concepts of how light regulates our biology.

You can’t call yourself Whole Foods Market without offering some whole foods.

In fact, daylighting is like the organic food section of the grocer’s shelves because it caters to the growing number of people who understand how long-term investments in better health result in improved wellbeing.

You don’t need a degree in illuminating engineering to know that a room with a view, one with windows that let in natural light, is what we desire—inherently we just know. Alternatively, “to never see the light of day again” is a hopeless and foreboding punishment.

For example, imagine finding yourself imprisoned in solitary confinement, in a small gray dingy cement room, deprived of any outside light source, with only an old T-12 fluorescent lamp flickering overhead. It’s a miserable and gloomy image.

In contrast, imagine instead an overhead skylight as the light source, with sunlight illuminating the small room throughout the day, changing hues and intensities. The high-noon light is sunny and bright. At dawn and dusk the light softens to a warm glow—plainly, a less disheartening picture because you can measure the passing of time by the sun.

In fact, though our internal biological clock is generated by the PER protein, we still synchronize our daily circadian rhythm with sunlight. The sun regulates our 24-hour cycle, according to research by neuroscientist Dr. Takahashi of the Howard Hughes Medical Institute, whose team discovered the clock gene.

And our daytime alertness pattern is also mediated by light exposure to our eyes. Melatonin is the hormone that induces sleep. Inhibited by light, and triggered by darkness, melatonin levels peak at night. In fact, all the cells in our body go through an activity rate cycle.

Our exposure to various color spectrums, too, affects our biology, as demonstrated by Dr. Brainard at Thomas Jefferson University, who discovered a new photoreceptor in the eye, distinct from rods and cones. Unlike electric lighting, the sun is a very nearly perfect light emitter of all visual color temperatures—approximating a black body radiator.

But if you’re not a tree-hugger looking to offer the healthiest possible environment for building occupants, daylighting has economic benefits that go well beyond the energy savings. People who work in properly day-lit facilities perform better. Students secure higher grades, office worker’s sick days are less frequent, and factory employees produce fewer defective products. Occupant benefits have been well documented by the Heschong-Mahone Group (now the TRC Company).

Despite its considerable benefits, daylighting is not frequently demanded as the primary light source. But it should be. In a report, “The Seven Market Obstacles to Daylighting,” Eneref Institute examined the difficulty that daylighting technologies have had in penetrating the lighting market. A major obstacle is that commercial lighting projects are too often driven by payback calculations of energy, opting for short-term ROI over long-term benefits. Yet, over the last few years, Eneref has gathered a collection of forceful endorsements for daylighting from people attesting to the benefits they enjoy: building occupants, homeowners, architects, facility managers, and engineers.

Whenever practicable, skylights and windows should be specified as the primary light source, balanced with color-tunable white LEDs and controls, coordinated by a professional lighting designer. Many effectual daylighting products are available. Thermal barriers in windows prevent energy loss. The leading skylight manufacturers have long ago solved rain leaks, and polycarbonate make skylights practically indestructible.

The next time a bright young sales representative presents you with tunable-white LEDs, you should ask, “Do you serve skylights with that?”