Human-Centric Lighting (HCL) has been part of the smart building discussion for some years now but its implementation has so far been limited to only the most advanced facilities. While the biological benefits of the technology are proven, the technical and financial elements required for the widespread implementation of HCL in a broad spectrum of buildings has yet to be established. However, as predicted in our 2019 report, things are beginning to change for HCL as guidelines move towards standardization and the total cost of ownership for the technology is better understood. The next two to three years now promise to be a turning point for the proliferation of HCL across the commercial building landscape.

“HCL goes beyond simply providing illumination for the built environment. It manipulates the light output, triggering biological responses in the human circadian system, according to the objectives of the environment. HCL has demonstrated its ability to make workers more productive, to help patients heal faster, and enhance student learning,” reads our dedicated HCL report. “HCL technology seeks to realign us with our natural rhythms by mimicking the progression of sunlight throughout the day. A global market worth $849m USD in 2019 has developed around this technology and we expect it to reach $3.5 billion by 2024, a 32.75% CAGR over the 5 years.”

To reach these lofty expectations, widespread adoption of the technology must take place, and for that certain developments must take place across the industry. Standards are a key step for many building technologies and this has been slow to take shape for HCL. Currently, no standards have emerged from the leading industry bodies such as the American National Standards Institute (ANSI), International Electrotechnical Commission (IEC), or International Organization for Standardization (ISO). However, guidelines from organizations such as the WELL Institute, Underwriters Laboratories (UL), and the education-specific CHPS committee are evolving quickly to present a natural precursor to industry standards for HCL.

“As the understanding around the human circadian system has grown, organizations have been able to start codifying the strategies needed to support circadian system entrainment in the built environment,” writes Naomi Millán fo the Council on Tall Buildings and Urban Habitat, in an article for FacilitiesNet. “In the last two years, several guidance documents prescribe the necessary performance attributes of lighting systems for human health benefit. These include WELL v2 Q2 2019, UL Design Guideline 24480, and CHPS Core Criteria 3.0. In general, these systems specify how much light needs to be provided at the eye-level of facility occupants to trigger the circadian system.”

At the most basic level, standards will address the fundamental elements that make up an effective HCL system, such as configuration, brightness, and flicker rate. Since the emergence of electric lighting over 100-years-ago, we have seen increasingly intense use of light in our commercial real estate, facilitating bigger buildings and longer working hours. However, the growing intensity of light in our working environments has been attributed as a key cause of discomfort and even health issues for workers, including short-term problems such as migraine and sleep disorders, to long-term susceptibility to serious conditions such as cardiovascular disease, diabetes, and cancer. This is a key driver for the emergence of HCL in the workplace.

“The spatial configuration of lamps and luminaires is often such as to induce discomfort. The use of large areas of highly saturated colours can also cause discomfort for some individuals,” write Yoshimoto et al. in their paper Adaptation and Visual Discomfort from Flicker. “It is essential that the lighting industry does not repeat the mistakes of the past. Imperceptible flicker from lighting has adversely affected the lives of many, if not most individuals who suffer migraine and future generations should not have to bear this burden.”

We will also need to address the contentious issue of energy use that surrounds the development of HCL in our increasingly efficient buildings. The rise of LEDs has significantly reduced the energy requirement of lighting systems but the evolving science around HCL suggests that controlling light for the human circadian system may reverse efficiency trends, putting human health in direct conflict with our environmental ambitions. Despite lowering light intensity in many areas, recent studies suggest that the goal of ensuring all building occupants have sufficient light to trigger HCL benefits will actually raise lighting’s electricity demands. However, declining equipment costs should balance out the total cost of ownership for HCL.

“The energy implications of designing to address these possible physiological effects are not yet fully understood. Beyond the fact that the basic metric of luminous efficacy (lumens per watt) does not cover these other effects, the emerging science seems to indicate that addressing a holistic view of the human needs in most applications may mean a need for increased light and associated energy use by electric lighting systems,” explains a 2020 report by Safranek et al. “Energy use may increase between 10% and 100% because of increased luminaire light levels used to meet circadian lighting design recommendations.”

The key driver for HCL, however, is worker productivity, which has proven to increase with the health and wellness of building occupants. Better sleep leads to greater alertness, better health leads to fewer sick days, and the better mood of employees working under HCL light can improve focus and collaboration, all combining to increase productivity. So, while standards will need to solve the technical configurations required and the industry will need to balance the total cost of ownership, productivity gains will drive HCL adoption forward. In the pandemic era, HCL will also offer another health feature for buildings to attract tenants and assure occupants.

“HCL is an increasingly common topic for discussion among facility executives. HCL has already been employed in facilities to increase occupant wellness by maintaining their circadian rhythms and improve productivity by stimulating the natural cycle of melatonin and cortisol,” says Christopher Johnston, Director of Total Sustainability, Energy Focus, Inc. “While its adoption is currently limited to more upscale facilities, lighting control technology is rapidly advancing with cost of ownership declining and will likely be attainable for most facilities by 2023.”

While the pandemic may have significantly disrupted our commercial real estate activities, the increased focus on public health is driving human-centric and health-focused building technologies, such as HCL. A wave of new investment to facilitate the safe return to the workplace after COVID lockdowns and widespread stay-at-home orders, will overcome the disruption and keep HCL on track to meet its strong growth expectations. The next two to three years could see a turning point in the adoption of HCL, not just for the smartest buildings but for a wide range of commercial real estate looking to survive and thrive in the post-COVID era.

“HCL is an inevitable reality for the future of lighting. Results of ongoing and future HCL pilots and installations will continue to demonstrate the benefits of the technology and highlight the negative health and productivity impacts of non-HCL solutions,” explains our comprehensive 2019 HCL report. “It may take some time but as the cost of tunable lighting comes down, the lure of health and productivity benefits will make HCL a standard feature in lighting for all kinds of buildings.”