Trends in Daylighting and Tunable Lighting

New strategies and technologies can bring health benefits to commercial and residential spaces
Sponsored by Marvin
By Juliet Grable
1 AIA LU/HSW; 1 IDCEC CEU/HSW; 1 GBCI CE Hour; 0.1 IACET CEU*; 1 AIBD P-CE; AAA 1 Structured Learning Hour; This course can be self-reported to the AANB, as per their CE Guidelines; AAPEI 1 Structured Learning Hour; This course can be self-reported to the AIBC, as per their CE Guidelines.; MAA 1 Structured Learning Hour; This course can be self-reported to the NLAA.; This course can be self-reported to the NSAA; NWTAA 1 Structured Learning Hour; OAA 1 Learning Hour; SAA 1 Hour of Core Learning

Learning Objectives:

  1. Describe the connection between natural sunlight and well-being, and the role of the body’s circadian rhythms in promoting overall health.
  2. Identify design trends in daylighting and the use of natural light in both residential and commercial projects.
  3. Discuss innovations in fenestration that are facilitating and/or replicating natural light conditions and diurnal cycles.
  4. Explain how tunable lighting can impact the well-being of building occupants by mimicking natural light conditions.

This course is part of the Custom Home Academy

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A Dearth of Daylight

Ironically, many people suffer from the opposite problem: not enough exposure to natural light during the day.

Exposure to high-intensity blue light is key for regulating circadian rhythms; however, people are spending more and more time indoors, many in buildings without adequate daylighting. According to the U.S. Environmental Protection Agency (EPA), people spend 90 percent of their time indoors. If this time is spent in buildings with inadequate daylighting, it could be enough to disrupt circadian rhythms and impact the quality of sleep. Fortunately, there are many ways to bring natural light into buildings, to the great benefit of building occupants.

Glass, Daylighting, and Well-Being

There are several key reasons to promote daylighting in buildings. First, daylighting reduces the need for artificial lighting and makes buildings more energy efficient. Second, daylighting is a biophilic design strategy that connects building occupants to aspects of the natural world, including fresh air, sunlight, and views of the outside. Daylighting can promote social interactions and help create feelings of well-being in building occupants. Finally, exposure to daylight supports our circadian rhythms and, by extension, the physiological processes that are vital to good health.

Many studies have quantified and documented the positive impacts of daylighting on the health and well-being of building occupants. Daylighting can promote employee productivity, help reduce absenteeism, and even boost retail sales. In health-care settings, daylighting and views of nature may aid in healing and reduce reliance on certain medications. The role of daylight and artificial light in supporting circadian rhythms is a newer field of research, but an exciting one.

Designers can create spaces that ensure occupants are exposed to natural light throughout the day, whether through the placement of windows, skylights, and/or through open plans that ensure all occupants have access to natural light. Equally important, glass and shading options can also help balance the need for natural light with control of solar gain and glare.

Though many daylighting strategies will support all of the goals mentioned in the previous section—energy efficiency, occupant well-being, biophilic connections, and circadian system regulation—it is important to understand that some design features will only address one or two of these goals, and that special strategies might be required to promote “circadian lighting.”

Although people are exposed to lights of all kinds throughout the day and night, most of this light exposure is in the form of electric lighting. Studies have shown that the light needed to stimulate the human circadian system is at least 10,000 times greater than the amount needed to support visual tasks. If a person is almost never exposed to natural light, they may not receive sufficient light stimulation to support normal circadian functions.

The circadian system is extremely sensitive to short-wavelength, or blue, light, while the visual system is most sensitive to longer wavelengths.16 Consequently, lighting design may be adequate for supporting visual tasks—it may reduce reliance on electric lighting and even promote well-being of occupants—but it may not have the intensity or spectral qualities that beneficially impact the circadian system.

Now let’s look at some tried-and-true strategies for effective daylighting.

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Originally published in Architectural Record
Originally published in October 2020