The latest report from Memoori estimated an $849 million global market for Human-Centric Lighting (HCL) in 2019 and predicts this to reach $3.5 billion by 2024, representing a 32.75% CAGR. While greater exposure to potential customers and reductions in the overall cost of systems will act as drivers for HCL adoption, the key factor for the growth of the emerging technology is the HCL industry’s ability to prove what it promises.

“Human-Centric Lighting, as the name suggests, is lighting for humans. HCL goes beyond simply providing illumination for human environments, to manipulating the light output to trigger biological responses in humans according to the objectives of a space. HCL has demonstrated its ability to make workers more productive, to help patients heal faster, and students learn better, simply by tuning into our evolutionary link to the natural rhythms of sunlight,” explains the report: The Human Centric Lighting Market 2019 to 2024.

The theory behind HCL is compelling and based on recent scientific breakthroughs. Around the turn of the millennium, the discovery of non-visual photoreceptors in the eye established the link between light and the circadian system, our internal body clock, which controls the release of certain hormones, among other things. The evidence strongly suggests that, over millions of years of evolution, human biology has developed its diurnal patterns in large part by reacting to the different wavelengths of sunlight emitted over the course of the day.

The blue-rich sunlight emitted in the morning hours wakes us up, gives us energy, and brings us to peak cognitive performance as we approach the whiter light of noon. As the afternoon progresses, blue wavelengths of sunlight diminish and the red end of the light spectrum increasingly dominates, making us more comfortable, creative, and social. The gradual reduction of blue wavelengths sets us up for a relaxed evening and the eventual extirpation of all sunlight at sunset triggers the release of melatonin, the sleep hormone.

Our control of electricity, the invention of artificial electric light, and the subsequent electrification of our modern society has disconnected us from that natural rhythm of light by bombarding us with blue-rich white light from luminaires, screens, and street lighting, late into the night. This theory is being used to explain the increase of sleep disorders in “modern society” but most acutely in those who stare at screens and spend much of their day in artificially lit environments. It’s not just sleep that is effected either, experts have linked “unnaturally” lit lives with a variety of physical, mental, and emotional conditions, as well as declines in a variety of performance metrics.

By mimicking sunlight patterns in our artificially lit environments, “HCL seeks to realign us with our natural rhythms by mimicking the progression of sunlight throughout the day. In doing so, it can improve occupant’s health and wellbeing, and therefore their ability to heal or concentrate, leading to improved recovery rates and productivity, for example. HCL applications have arisen in healthcare, offices, retail, hospitality, residential, and many more verticals, creating a confusing and fragmented market full of opportunity,” explains the report.

HCL is not lacking in promise but for that kind of widespread, multi-vertical adoption to come about, the industry will have to prove its ability to fulfill those promises by putting tangible numbers behind the benefits.

Some opposition to HCL does exist, and the report highlights key arguments from the neuroscience, medical and engineering fields. The key element of this opposition is our lack of understanding of the relatively new science behind this technology and its application. From the medical perspective, for example, the fact that HCL consents to triggering human biological responses is enough to say that higher standards of testing should be necessary.

“Light works as if it’s a drug, except it’s not a drug at all,” states Dr. George Brainard, a well-known researcher in the field light and biology. And in that sense, it falls outside the scope of medical and pharmaceutical testing, and Brainard thinks that maybe it shouldn’t. The argument is that if light acts like a drug, then we should treat it as a drug to ensure the highest levels of safety. “If this is the case, why don’t we follow the medical industry and their best practice?” asks Brainard.

The early signs, however, suggest that the evidence supports HCL as a beneficial health, wellbeing, and productivity booster for people that spend much of their day in artificially lit environments. The report highlights the results of the latest HCL studies and pilot projects around the world, by vertical, to show how HCL is helping buildings achieve the objectives of their spaces and raise the general level of health and wellbeing amongst occupants. To reach its potential, HCL must prove itself as safe for the user and beneficial for the customer, while also highlighting the negative impacts of our current lighting systems.

“The vast majority of research supports the basic principles of HCL. While further technological testing and scientific exploration is encouraged in order to develop greater accuracy and better guidelines, current theories suggest that continued investigation is more likely to strengthen the case for HCL than weaken it,” concludes the report. “The business case for HCL would not only be supported by evidence of its health, wellbeing, and productivity benefits, but also by a growing body of research about the harmful effects of our current non-HCL lighting systems.”