By Neall Digert, Ph.D., MIES
From the June 2023 Issue
With Americans, on average, spending more than 90% of their time indoors, cultivating a healthy indoor environment that meets sustainability goals can begin with sound daylighting strategies. The effective use of daylight in today’s buildings not only plays a significant role in achieving energy efficiency, but also successfully nurtures the occupants within. Each day, new research, case studies, design guides, and design standards magnify the importance of daylight as a source of interior lighting that drives human health, productivity, and happiness.
Each day, new research, case studies, design guides, and design standards magnify the importance of daylight as a source of interior lighting that drives human health, productivity, and happiness.
Since the pivotal discovery of the intrinsically photosensitive retinal ganglion cells (ipRGC), and research that documents the ipRGC’s role in the human circadian cycle and health, physicians, researchers, scientists, engineers, and designers have worked together to develop and apply evidence-based design with the artful and beneficial application of daylight and views to modern buildings.
Daylight And Wellness
Today, the ever-growing body of research and design case studies continue to emphasize the importance of daylight and outside views for the psychological and physiological benefit of building occupants. Scientists at the Lighting Research Center (LRC), in Troy, NY report that quality exposure to daylight (as a source of interior illumination) results in improved occupant comfort, mood, and productivity, and decreased stress and rates of depression.
Research and evidence-based design activities show that providing building occupants with daylight provides the mental and visual stimulation necessary to regulate human circadian rhythms and the production of neurotransmitters, such as serotonin. The human circadian rhythms are the body’s natural clock. When your body is exposed to daylight, your brain releases neurotransmitters in response to the changing intensity and spectral content of daylight over the course of the day. Ultimately, these neurotransmitters play important biological roles in telling your body to wake up during daylight hours, and when darkness hits, enabling your body to fall asleep.
By exposing your body to daylight throughout the day, your healthy human circadian rhythm will have a significant role in regulating your sleep-wake cycle and have a positive influence on your eating habits and digestion, body temperature, hormone release, and other important bodily functions. Serotonin, sometimes known as the happy hormone, leaves us feeling more energized, happy, and well-rested while fighting and reducing stress, anxiety, depression, and potentially minimizing seasonal affective disorder (SAD).
The benefits of natural light don’t just apply to our physical well-being, but also to our psychological health and mood. As living beings, we feel the benefits of being exposed to daylight, and when we don’t have it, we crave daylight and views.
The end result is that psychological and physiological health go hand in hand, and access to daylight and views are key elements of a building’s design that improve the indoor environmental quality of a building for human wellness.
Daylight And Productivity
In addition to nurturing the health and wellness of occupants within a building, daylight-filled environments have proven to inspire and lead to a more productive atmosphere. This is because when employees are fulfilled in their workplace environment, they are more engaged, produce higher quality individual work, and are much happier in general, which creates a more enjoyable workspace.
A research poll of 1,614 North American employees found that over a third of employees feel that they don’t get enough natural light in their workspace. About 47% of employees admit they feel tired or very tired from the absence of natural light or a window at their office, and 43% report feeling gloomy because of the lack of light.
The same Future Workplace poll conducted for the Harvard Business Review found that 70% of people reported that access to natural light improved their work performance.
To this end, it’s no surprise that a recent report by sustainability consulting firm Stok titled “High Performance Buildings and the Evolution of the Workplace” identified daylighting as the No. 1 priority for employees.
Daylight As A Disinfectant
UV light has been used for decades as a natural disinfectant. It’s used to clean drinking water as well as naturally eradicate organisms that could be potentially harmful in healthcare facilities.
Now, a recent study published in the journal Microbiome has shown us that rooms exposed to daylight had fewer germs, a similar effect as UV light. In fact, the study revealed that the daylit rooms had about half the viable bacteria (those that are able to grow), compared to dark rooms.
Daylit rooms were also shown to have less of the types of bacteria that result from the shedding of human skin (including some that are known to cause respiratory disease), and more closely resembled outdoor bacterial communities. Concluding that daylighting may have been about visual comfort or broad health in the past, but now we can say daylighting influences air quality and works as a disinfectant, too.
Daylight, Energy Savings, And Sustainability
Facility executives understand how important it is to be environmentally responsible. As a result, many facilities choose to go green through sound daylighting strategies, and it’s easy to see why.
The buildings sector has a substantial carbon footprint when both direct and indirect emissions are taken into accounted. According to the International Energy Agency (IEA), the buildings and building construction sectors, combined, are responsible for 30% of total global final energy consumption and 27% of total energy sector CO2 emissions.
Natural light is the most sustainable lighting option available; it is also a free renewable resource that offers numerous incentives beyond knowing you are behaving in an environmentally responsible way.
Natural light is the most sustainable lighting option available; it is also a free renewable resource that offers numerous incentives beyond knowing you are behaving in an environmentally responsible way. Electricity continues to be the primary energy source for commercial buildings and single largest expense. Even setting aside the fact that electric lighting can impact negatively on productivity and consequently output and revenues, they are expensive to operate.
Today, highly efficient and advanced daylighting technologies are available to reduce the need for electric lighting during the day without causing heating or cooling problems, but actually improving it.
Digert, Ph.D., MIES, Vice President, Innovation and Market Development, Kingspan Light + Air | North America, has over 30 years of consulting and education experience working in the energy/lighting/daylighting design and research fields, specializing in the design and application of advanced lighting and daylighting systems for commercial building applications.
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