What is Human Centric Lighting?

Human Centric Lighting (HCL) is the new buzzword in the professional lighting industry. The research it’s based upon is extensive and maybe not what you would consider light reading. We’ve asked our expert Lars-Fredrik Forberg to get you up to speed.

Civil engineer and HCL-responsible Lars-Fredrik Forberg has been developing Human Centric Lighting solutions for the past 3 years. In his mind HCL is next disruptive technology in the lighting industry.

Just to start out with the basics, what is Human Centric Lighting?

Human Centric Lighting puts focus on both the visual and non-visual effects of the lighting. People need not only light to perform visual tasks, but light is also an important “time-reference” for our internal clock. 

That's interesting. How exactly does light affect my brain?

The brain is affected by light in two ways. First we have the visual path which is connected to the brains interpretation of visual images. And then we have the circadian path where photoreceptors in the retina, called ganglion cells, are affected by the amount of blue light they’re exposed to.  These cells set the biological clock that synchronizes our bodies with the external cycle of day and night. A major output of the biological clock system is the production of the hormone melatonin – a “sleep hormone”. This production in the pineal gland varies with the time of day. Melatonin is secreted at night and has minimal levels during daytime. Light also induces the release of

Can artificial lighting really be that important? I rarely hear anyone complain about the light in their workplace?
People do not complain about the lighting as long as you have enough of it, with a decent quality. But when the light levels are low or when the light sources causes discomfort glare, people will complain – or their bodies will.
And what kind of bodily discomfort can wrong lighting lead to?
Discomfort glare and a low lighting level may cause headaches, neck or back pains, general fatigue and fatigue in the eye muscles. 

What are the positive non-visual effects when the lighting is correct?
Short-term bursts of cool white and intensive light may increase your concentration, without you knowing it. Or make you feel sleepier at night because you have shifted your daily rhythm a bit. Both are positive effects that you perhaps do not notice immediately, or at all.

Is HCL a new invention?
No, we have researched the effect of light on people for decades, if not centuries. What is new is that we have a new, cost-efficient and flexible light source – LEDs – that makes implementing Human Centric Lighting solutions easier and better. Still we need to do more research to learn about the optimal use of HCL.

So, who can benefit from HCL?
Everyone that spends the whole day, or parts of it, indoors. School children, office workers, elderly with dementia, shift workers etc.

But I have people at my workplace with all kinds of different tasks and working hours, it will surely be impossible to accommodate them all one particular light setting?
True, people also have various chronotypes, some are night owls whereas others are morning larks. To both, the timing of the light exposure matters and a one size fits all approach may not be the best way. It would be better to allow for individual settings of intensity and colour temperature (the whiteness of the light) at each work station.
This seems to me like it might be hard to achieve in a classroom, for instance?
Yes, for classrooms we think that designing the lighting installation to accommodate the sleepyheads may be the solution. For example, postpone the circadian phase-shifting, or activating, light in the morning to when they are most receptive to it. 

How is all this knowledge about how lighting affects our bodies transformed to lighting solutions?

The knowledge is the basis for the development of luminaires that mixes light from cool and warm white diodes.  So it’s kind of two in one solution that offers both the activating non activating light. And we also offer an intelligent control system that makes this tunability possible. These installations are currently more expensive than ordinary LED installations, but we expect the price difference to decrease in the future. 

But is Human Centric Lighting worth the investment today?

Yes, we think so although the payback time is hard to calculate because the ROI has all to do with the overall wellbeing of the end users.  Higher motivation, increased productivity and an improved sense of wellbeing are some of the documented effects of Human Centric Lighting.