ILP Manchester CPD Webinar: What’s healthy lighting really worth?

Jul 13, 2021 | CPD, Manchester LDC Webinar, Webinars

  1. CPD

What’s healthy lighting really worth? The million dollar question!

Dr Shelley James will share her latest research into the business case for ‘human centred’ lighting. She will introduce the latest scientific and commercial impact studies and examples of best practice from around the world. This is the first stage of the Luna Pro project that aims to raise awareness of the value of investing in lighting among the 80% of professionals who buy lighting with little or no formal training.  It builds on the global success of the original Luna campaign to raise awareness of the impact of light on health and wellbeing among young people that has already reached 1.8 million teens and growing. The Luna Pro project is sponsored by (in alphabetical order) Bios, Glamox Luxonic, Phos. Seoul Semiconductor, Signify and Zumtobel.

Speaker: Dr Shelley James, Age of Light Innovations.

Hosted by: David Coldron, Chair for ILP Manchester.

Q&A: Peter Harrison MBA CEng FILP, ILP Technical Director.


When designing interior lighting where employees have epilepsy, what controls would you apply to equipment used and how would that by specified?

Two main factors to consider. The first is flicker – for specific standards, please see notes in response to question below. But on a more general note, the lighting professional should select equipment that meets or exceeds the standards, paying particular attention to ensure compatibility of power supply, dimming and other controls to ensure that these do not introduce flicker into the system. Regular testing and maintenance should also be specified as we know that the performance of components changes over time. The second dimension to consider is contrast: people with photosensitive epilepsy are known to be particularly sensitive to extreme contrast, both in terms of the patterns in the space (e.g. blinds and geometric carpets with a strong orientation in one direction), especially when these cover a large area in the visual scene, and in terms of light-dark zones in the central visual field (e.g. a bright screen in a dark room). The lighting professional should work with other members of the design team to ensure an even distribution of luminance across the scene, ideally integrating sensors to ensure that balance is maintained at different times of the day and throughout the year. This article makes some useful points – noting that sensitivity varies with stress and other factors. This article offers more in-depth information about the neural mechanisms involved –

You mentioned a 35% increase in demand for healthy or human centric lighting. Is that demand being driven by Specifiers, designers or clients?

A quote from the report ( is here – ‘The growth of this market is driven by the high adoption of LED lighting solutions, initiatives toward establishing smart cities, and the rise in the demand for energy-efficient lighting solutions. ‘

It was interesting to note that productivity can be increased by up to 23% by installing human centric lighting. How can this be measured?

Productivity improvements are measured in response to the overall lighting environment rather than an individual luminaire. This report – offers a useful summary which then goes on to explain how the type of work and other factors such as age and gender can influence response. It is a relatively old report and was sponsored by Philips but does offer a balanced overview. Lighting in the workplace may influence employee performance in several ways. It may affect eye strain and visual comfort (van Bommel & van Beld, 2004; Boyce, 2003). Lighting may also influence cognitive performance and problem solving ability by interfering with physiological factors like circadian rhythms (Juslen & Tenner, 2005). Lighting can also impact on mood and interpersonal relationships at work and therefore job satisfaction (Boyce, 2003). This paper is also interesting as it describes different dimensions of performance in a real life setting and the link between ‘preference’ and performance very simply –

Where has this data (23% increase in productivity) come from again please? Which agency/uni/organisation has derived this data?

I am acutely aware of the risks of making exaggerated or unsubstantiated claims for lighting as it undermines the whole argument. I had originally taken the figure from this blog which references the World Green Building Council and Cornell University and thought I had found the back-up data in the academic references they cite – but I cannot find the 23% figure in these documents now. So, I apologise for any confusion and lack of rigour on my part: I will not use this figure again until I have tracked down the relevant references,

Quality was mentioned in respect to light panels. What is the measure for quality in this instance?

These figures were derived from conversations with a number of specifiers and manufacturers and represent a general ‘range’ rather than a specific metric or specification. As your members will know from experience, different manufacturers and models focus on different features but the standard includes elements such as the build quality of the fitting and components, the level of retrofit / circular components and the location of the light source (back lit or side lit).

Flicker was mentioned, what do you consider would be acceptable limits for controlling flicker?

Please see this paper that set out the current arguments and figures. Or see this article that reviews current specifications around flicker –

What 3 messages should we take away from your presentation?

  1. Good-quality lighting is an approach, not a product – designed for people and with people, not for the building.
  2. There is a compelling business case for investing in good-quality lighting for clients at every scale and at every stage in the value chain – from a short term cost per hour of running the luminaire over its lifetime and reduction in downtime for repair and replacement to improved  employee satisfaction, performance and retention and meeting sustainability goals. The next generation of full-spectrum, sensor-responsive products designed with the full life cycle in mind mean that solutions are simple, affordable and accessible.
  3. To be ambitious for our clients and make a stand for the best-available solution that they and the next generation can be proud of – consider whether you are contributing to an environment that you and your loved ones would be happy to live in.

I feel that post pandemic we have to be a better designed world, as offices get smaller (people working from home), developers will have to deliver better spaces to compete. Your thoughts?

Dr Peggie Rothe of the Leesman Index pointed out the results of recent employee satisfaction surveys that show that many employees prefer working from home in an environment that was not designed for work over an office environment that was. And lighting plays a big part in that. Employees have a new benchmark – and employers and property developers will need to take that into account in the way that they design and manage spaces in order to attract and keep tenants. At the same time the move towards hybrid home-office patterns will mean that developers will need to create spaces (including lighting design and specification) that offers lighting to support family members at different times of the day and Into the evening. A growing awareness of the need to reduce carbon – not only in terms of energy use but the embodied materials and transport involved in every dimension of the built environment is also changing the way that lighting is designed and specified.

Can we have a bit more detail on the lighting implement to aid dementia?

One way that lighting can support dementia care that has received a lot of attention recently is to use lighting to support the sleep-wake cycle as this has been shown to reduce symptoms such as sundowning – There are other functional considerations that are also important as people with dementia tend to be older with corresponding need for greater light levels for example. This website has some interesting information: Please see also a recent interview with Ed Russell of WCS Care who installed lighting in a care home in Warwickshire and has seen a marked improvement in patient symptoms –

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