Human centric lighting.

Not enough of the good natural kind and our circadian rhythms are affected and we function poorly. However, the opposite is also true — lots of exposure to good natural daylight and we gain real and palpable health benefits. With many humans spending up to 90% of their lives indoors, exposure to natural daylight can be hard to come by, this is where Human Centric Lighting (HCL) comes in. Human centric lighting is an emerging field that uses science to improve the lighting in our built environment to support our health. Here we look at human centric lighting, consider why we need it and discuss how we’re using it at Kiss House.

Human beings run on circadian rhythms generated by our exposure to daylight. The Sleep Foundation defines these circadian rhythms as “24-hour cycles that are part of the body’s internal clock… (that) are directly influenced by environmental cues, especially light.” These rhythms, “feed off daylight, telling us when to rest, wake and seek food and even help us identify when to heal,” according to “Architect”, The Journal of the American Institute of Architects. When we are regularly exposed to daylight, our rhythms can rumble along nicely, supporting us in our day to day lives. We sleep better, feel healthier and are more productive. In fact, Danish Studies suggested that people who were treated for severe depression whose rooms faced south-east, were discharged in almost half the time as compared to those facing north-west, because daylight was 17-20 times greater!

However, when our exposure to daylight is limited, circadian rhythms are disturbed. Lack of daylight, or over exposure to inadequate / artificial lighting, has regularly been linked to eye strain, insomnia, weight gain and lowered mental performance. Unfortunately, according to the U.S. Environmental protection agency, humans in modern cities spend upwards of 90% of their lives indoors, meaning they cannot to get enough exposure to natural daylight. A 2017 survey by Lutron Electronics focused on the impact of lighting on mood and health, it showed that 83% of UK office workers were frustrated by their workplace lighting, with 35% saying their existing lighting did not have a positive impact on their productivity. Findings revealed that 8 out of 10 office workers in the UK experience negative physical health symptoms because of inadequate lighting conditions. Half the participants experienced headaches, 48% experienced eyestrain and around 40% reported an increase in tiredness and fatigue.

The latest edition of the CIBSE TM40 Health Issues in Building Services stresses the need for “further research to establish metrics for lighting design that take circadian effects into consideration.” Unfortunately, while building standards are becoming more environmentally aware, the effect of a building on the health of its occupants still requires attention. This is where the field of human centric lighting is coming into its own. The basic premise is that the lighting we use should mimic the natural rhythms of daylight because, according to scientists at the Lighting Research Centre (LRC) “day lit environments increase occupant productivity and comfort and provide the mental and visual stimulation necessary to regulate human circadian rhythms.” The World Green Building Council says workers feel more engaged when they work in natural light, are more encouraged to collaborate with team members, and stay better focused on tasks. Whilst most studies have been undertaken within the workplace not in the home, there is no reason to believe that the effects would not be the same within residential settings and this got us really interested at Kiss House.

As we began to explore human centric lighting, we began to consider how we might integrate it into the lighting in Kiss House homes as part of a wider lighting design project. As journalist Stephanie Brick states in the Washington Post, “Lighting serves an imperative function, but it also plays a vital role in its form and the environment it creates. A supermarket with dingy lighting communicates seedy options and lower quality; a restaurant with fluorescent lighting v’s candlelight is a cafeteria v’s fine dining. Lighting creates and defines ambiance, and the same is true in your home.” Too often, she explains, we “settle” for lighting accepting it “as good enough.” “We settle for the ceiling pendant original to the kitchen despite the shadows it casts on the work surface when you stand at the counter. We accept the recessed can lights in the living room despite the harsh glare when you sit on the sofa (or simply avoid the glare by using the television as a sole source of illumination as the night goes on.) We choose between the ceiling fan and the recessed lights, for simultaneous use creates a headache-inducing strobe effect.” It should not have to be this way.

As we worked on our lighting design, concept and strategy at Kiss House we began to work to combine great aesthetic design with human centric lighting in the hope of achieving something exceptional. The work is still in development, but there is a huge opportunity here. As we dived deeper into the research, we discovered that The Well Building Standard (developed by the WELL Building Institute “to transform health and well-being with (a) people first approach to buildings, organisations and communities”) also includes guides specifically relating to lighting. This guidance suggests that a best practice approach should aim “to minimise disruption to the body’s circadian system,” stressing that lighting should “enhance productivity, support good sleep quality and provide enough visual acuity when needed.” Having been keen to sign-up to The Well Building Standard already we got very excited! Our next step was to engage with Dr Neil Haigh, Chief Technical Director of lighting specialist ColorDyne to begin to explore the possibilities. This is a work in progress that we look forward to updating you on in time. In the meantime, we wanted to share more on human centric lighting and why it is important to us with you, so we asked Dr Haigh to share some of his thoughts and expertise.

What is human centric lighting?

“Human centric lighting (HCL) is where the choice of lighting in a home or workplace is centred upon the health of people. That goes beyond the general requirements for simply lighting a room and preferably, saving energy in the process. HCL is primarily about the needs and considerations of the people who are living or working within the lit environment.  It is surprising to think that this might ever be overlooked, but in many cases it has. The scientific picture for HCL is not yet complete, but we do know that it is now especially important to approach lighting in the home and workplace from the human centric perspective. This means that the light sources used in human centric lighting will need to be adaptable and versatile.”

“Surprisingly, before we even consider human centric lighting for the home, we should reflect upon the fact that we often choose our residential lighting from an ornamental or product design perspective rather than thinking about the specific lighting task or function (other than in the most general terms). For example, halogen style downlighters in living rooms and kitchens are an extremely wasteful and inefficient way to provide ambient lighting for a room, you are mostly lighting the floor rather than any preferred surfaces.

However, they are very common in the home! Filament type lightbulbs that cannot, by design, illuminate the room are popular because they look great which is why people buy them. There is also a lot of confusion in the marketplace when people are buying lightbulbs on energy saving principles alone. With a human centric approach, we might not only improve the quality of the lighting within the home but also help clarify and explain lighting much more than we do so now. If you start asking the question, what do I really want the lighting in my home to do for me? Then you have already made an inroad into the human centric lighting mindset. If this means that you when you are reading your favourite book the lighting is perfect for the task, or that your lighting at night does not startle you into full alertness, then you are already thinking in a human centric lighting way.”

“Human centric lighting establishes a critical mindset that addresses the impact of light and lighting upon human health. We all feel better when we have been out for a walk during the day or maybe even stepped out of the office for 20 minutes at lunchtime. We now have the science to support why we feel that way. There are too many workplaces in the UK that do not provide their personnel with good access to natural daylight and that is for the entirety of the working day! So, one role for human centric lighting is to think further about improving upon and increasing our access to natural daylight as much possible. The needs for the artificial lighting will then follow and incidentally, I think we might see the increased use of skylights (both natural and artificial) for use in room lighting. It might become much more commonplace for the home and workplace.”

“Human centric lighting implies that the lighting will be in harmony with our lifestyle for the whole of the day — whether we are awake or supposed to be asleep, the lighting will know what it is supposed to be doing.  Human centric lighting means we will have a good idea of what the lighting will be doing for us in terms of our needs.

HCL takes into consideration the choice of light spectrum, intensity, brightness and the shape and patterns of the light we use. Above all though, in all we do with human centric lighting we will be considering the timing of the lighting. This means that during the morning, afternoon, evening and night-time, we are aware of what exposures to light we should be getting and then adjusting and altering the lighting to suit. For example, we have already seen a trend to remove the blue light content from smartphones and tablets in the evening, and the reason for doing this is entirely associated with human centric lighting. Once we transition from thinking about the light output from a small smartphone screen to what is happening within all the lights of the house, then we are in a human centric way.”

“At ColorDyne Lighting we have taken steps to address the next phase of lighting for the home. We already have tuneable lighting systems under evaluation in several universities across the UK. It is important that the artificial daylight spectrum is tuneable, so we can change the daylight spectrum from a light fitting in the room to follow any natural trends or environmental setting we wish for. This could be a sunset occurring anywhere around the world. The ColorDyne approach goes beyond commonplace R-G-B colour mixing and is instead thinking about recreating the full spectrum of natural daylight where we might need this. We are soon to start a lighting trial where we can compare the use of artificial daylight replication to the light produced by conventical fluorescent and white light LED lighting. The outcomes for this trial could be important for commercial spaces such as offices, care homes, and conference centres etc. Residential lighting will be the next step for this important work.

It is exciting to explore with Kiss House how we may work together to bring harmony into the home through lighting.”

Many thanks to Dr Neil Haigh for his insights. We hope you enjoyed reading abut his insights on human centric lighting.

Best wishes

Kiss House team

Resources

Multiple benefits of human centric lighting design

Shining a light on health and wellbeing

Depressed patients hospitalized in south-east facing rooms are discharged earlier than patients in north-west facing rooms

The benefits of natural light

International Well Building Institute: Light

Health and wellbeing in building services 

Indoor air quality

Benefits of natural light in the workplace

Bringing the benefits of natural light indoors

Building for body clocks: How human centric lighting can improve people’s wellbeing and performance

Research into office lighting reveals negative impact of poorly lit workplaces

Why you should care about lighting in your home

Lighting Research Center