HCL - 

Human Centric Lighting

WHAT IS HCL?

What does that mean? Quite simply: people are at the heart of a lighting concept. At the start of the 21st century, researchers discovered a third photoreceptor in the human eye that has nothing to do with actual visual ability. Instead, it regulates our internal clock, controls our day-night rhythm and influences our well-being. 

NEW REQUIREMENTS FOR ARTIFICIAL LIGHTING

This discovery made it clear that artificial lighting must meet far more requirements than simply providing light. Regardless of the sector. Lighting in the workplace, for example, should motivate and promote concentration. At home, on the other hand, it should be cosy and pleasant after work. 

The biological effects of light cannot be dismissed and are therefore receiving increasing attention in the planning of lighting concepts.

THE NATURAL RHYTHM WITH HCL 

HCL skilfully translates the natural interplay of daylight, twilight and night into interior spaces, thereby harnessing the biological effects of different lighting atmospheres. As a result, biologists, psychologists, architects and lighting designers now often work hand in hand. 

Life is governed by time and space. 365 days, 24 hours, day, night, seasons in different places – everything has a rhythm and a dynamic. Over time, humans have become accustomed to this natural rhythm and the body has adapted to it. With HCL lighting design, we replicate this biological process; better still, we can even counteract bad habits, adapt rooms with little or no daylight to it, and positively influence our lives with artificial, dynamic lighting. Dynamic light brings greater quality of life, productivity and well-being.

The human biorhythm

HCL AND HEALTH FACTOR 

Proper lighting also plays a role in the healthcare sector. Light therapy is used to treat conditions such as depression and symptoms of fatigue. Dynamic lighting helps to restore the human biorhythm and reset the body’s internal clock. We sleep better, feel more alert in the mornings and are better able to concentrate at work. HCL lighting concepts are now also being used in hospitals and care homes. 

IN A NUTSHELL: 

Morning: Sunrise – it gets light, the body produces hormones to wake us up and get us fit

Midday: Daylight – light with a high blue component and brightness, keeps us awake and focused

Evening: Warm sunset light – winds the body down, relaxes us and makes us sleepy

HUMAN-CENTRED LIGHTING CONCEPT 

HCL lighting concepts therefore utilise lamps and light sources with various luminous intensities and color temperatures that simulate the natural rhythm at different times of the day. The key factors are those modelled on daylight:

1. Illuminance 
2. Light direction 
3. Color temperature 

are just three of many. Smart lighting controls can be set up to automatically regulate the sequence depending on the season, time of day and time of year. Of course, this can also be controlled manually. Naturally, the best options are continuously adjustable and dimmable systems that are barely noticeable. 

HCL APPLICATION AREAS 

Three practical applications for HCL concepts in which proven effects are achieved: 

1. Office / Workplace 
2. School / Educational institution 
3. At home 
   
   

HUMAN CENTRIC LIGHTING IN THE OFFICE 

Dynamic lighting based on the HCL principle is particularly beneficial in workplaces with limited natural light. It is important to consider not only light intensity, but also the direction of light and color temperature. Stimulating, direct morning light at the start of the working day, cool, slightly diffuse daylight to counteract the midday slump, and a gradual transition to warmer colors of light as the working day draws to a close.

Various companies report an increase in their employees’ performance and productivity, which outweighs the additional costs of an HCL concept. The general mood and well-being of staff are also said to have improved.

HCL IN SCHOOLS 

Teachers and lecturers can select the right lighting atmosphere for different requirements at the touch of a button.

• Cool white, relatively direct light to energise and wake up pupils in the first lesson of the morning 
• Natural, non-directional daylight for focused work and during tests and exams 
• Warm white light to calm heated atmospheres and agitated pupils after hectic lessons or tests

Several studies have also revealed remarkable improvements in performance in this area through the use of dynamic lighting in the classroom. Not only lower error rates, but also general effects, such as children being more sociable and well-balanced.

DYNAMIC LIGHTING AT HOME 

All these findings can, of course, be applied to the home as well. To achieve this, we need different light sources that are used at different times of the day. 

One good idea, for example, is a daylight alarm clock, which stimulates the body’s natural hormone balance with a simulated sunrise. Large-area light sources with a daylight-white color of light are ideal for rooms with little or no natural light. To aid relaxation in the evening or in the bedroom, dimmable lamps with a warm color of light are ideal. 

This way, we can adapt the lighting atmosphere at home to our circadian rhythm at any time, thereby doing something good for our health and well-being.