Bringing the outdoors inside

by Henrik Clausen, Director of Fagerhult’s Lighting Academy

Natural, outdoor light is a vital component in our everyday health and well-being. But while our ancestors spent almost all their time outdoors, their biological clocks synchronized to the 24-hour rhythm of the Earth's rotation, people today spend much less time outdoors during the day, reducing the healthy impact of their exposure to natural daylight.

To make matters worse, extended exposure to light at night can lead to what is known as circadian disruption, where our body’s alignment with day-light and night-time becomes disturbed. Disrupted circadian rhythms have been shown to be associated with a number of health issues including depression, bipolar disorders, cardiovascular and reproductive problems, negative impacts on the immune system and seasonal affective disorders.

Such disruption is also being exacerbated by the impact of the coronavirus pandemic and the requirement for people to stay indoors for longer periods than normal in order to reduce the risk of infection.

Dynamic Light

In an effort to address the lighting issue, the industry has developed a concept called Human Centric Lighting (HCL), which focuses on bringing the dynamics of natural daylight back into people's everyday lives through biologically effective electric lighting. The technology involved helps the human body to stay aligned with the natural circadian rhythms that humanity has been familiar with throughout much of history.

Over the course of a day, HCL simulates indoors the dynamic changes in light intensity and colour temperature of light found outdoors. In doing so, HCL provides biologically-effective lighting to boost concentration and productivity in daytime working and learning environments. HCL systems also consider the effects of light exposure on both the biological and emotional aspects of human physiology, keeping the human body in sync with the natural 24-hour cycle.

Over the course of a day, HCL simulates indoors the dynamic changes in light intensity and colour temperature of light found outdoors.

HCL can be applied in all indoor environments. This is important to note, given that offices, schools, commercial and industrial facilities often use efficient LED lighting with cool colour temperatures in order to keep people more alert, concentrated, responsive and productive.

While this has its advantages during the day, such bright light is less beneficial when extended into night-time hours. And since a large part of the population often works or learns deep into the night, such people are at risk of circadian disruption, as night-time exposure to high levels of brightness suppresses melatonin secretion, causing the body to adversely reset its biological clock.

Such issues have prompted numerous scientific studies in recent years. When developing lighting systems, Fagerhult carefully monitors the latest papers on lighting research, referring to scientifically-derived and peer-reviewed results from recognised universities.

Molton Brown

We also actively support universities in their research, striving to create and sustain those benefits created by close cooperation between the academics providing the research and those industries which need it. We use these scientific findings in our product development, in the programming of our lighting control systems, and in our work with lighting designers, architects and engineers.

Recently we posed the question: can daylight act as a point of inspiration for a new indoor lighting design concept, bringing the qualities of dynamic light into our work environments? The answer, simply, is yes.

But getting into the detail, for the past four years Fagerhult, together with lighting technology groups Tridonic, iGuzzini and Zumtobel, has teamed up with Aalborg University in Denmark to develop and scientifically validate the ambitious Double Dynamic Lighting (DDL) concept.

DDL is a dynamic indoor lighting system for office environments which demonstrates how advanced responsive lighting technology can bring the office lighting to life. It does so by bringing the qualities of natural light into the office and so improves the indoor lighting environment and work engagement. As a white paper produced by the team behind the research argues, DDL refers to the multisensory human perception of unpredictability, naturalness, flow of light, light modelling effect and personal light zones.

The results of field studies show that it is possible to define dynamic light settings responding to the dynamics of daylight through a combination of direct and diffuse lighting. DDL was shown to have a positive impact on perceived atmosphere, visual comfort and work engagement, compared to static lighting.

Research also showed that the combination of directional task lighting and diffuse ambient lighting, when responding to sky-types and measured daylight level in the space, was favoured, versus static standard diffuse lighting.


Henrik Clausen on DDL

The aim of the DDL study was to investigate how a combination of daylight and smart dynamic lighting could contribute to better health and well-being on the part of occupants.

Participants in the research said the dynamic lighting made the perceived atmosphere more comfortable, while they also experienced positive effects in their motivation, concentration and workflow.

The DDL research will help plan for future workplaces, including schools, creative facilities and healthcare environments. It is clear that there is significant benefit to be had from using lighting as a tool to increase the quality of life for occupants in such spaces and beyond.


We believe DDL is a significant step forward in achieving better light for all.


Notor 65 Dynamic