The Future of Human-Centric Lighting: How Tunable Light and AI Will Transform Our Spaces

In the last few weeks I've had the pleasure of leading BA (Hons) students at the KLC School of Design in their lighting design unit. This is an annual gig, and it's wonderful opportunity for me to explore notable changes in the art of lighting design, year-on-year.

Last year (2024) we talked about human-centric lighting, this year the emphasis has moved to programmable tunable lighting and the developments in AI that are turning the spotlight (sorry!) on home lighting as a significant contributor to health and wellbeing. 

Here are my (early) 2025 notes, which describe the sci-fi future of home lighting that is already possible. 

Lighting has evolved and is no longer just about visibility; today, human-centric lighting (HCL) is shaping how we feel, work, and even age - tuned lighting is likely to become a client expectation, and not just a luxury. By understanding how light interacts with our circadian system, we can now programme artificial light to align with natural processes, supporting sleep, mood, and overall health.

With versatile LED technology, tunable lighting, and AI-driven controls, the future of lighting is shifting toward radical personalisation: adapting not just daily, but seasonally, and even to individual biological chronotypes. In these notes, we’ll explore the science behind human-centric lighting, the impact of melanopic lumens, and the exciting future where AI-controlled lighting enhances our longevity and well-being.

Tunable White Light - A Definition

Tunable White Light refers to a lighting system that allows an intentional and dynamic adjustment of colour temperature and intensity, enabling users to modify their experience of the lit environment. Installing tunable lighting makes it possible to programme 'natural' transitions of artificial light, from warm white in the morning (e.g., 2700K) to cool midday daylight (e.g., 5000K+), and then back to warm-toned light for the evening. 

The prescription of daily light can also flex between winter and summer, relying on warmer-toned light in winter (e.g. here in Northern Europe where winter daylight can be cold and grey) transitioning to cooler light in summer when the climate is warmer. Using sensors, tunable lighting could react in the moment to current weather system and the prevailing conditions outside. 

This adaptability supports circadian-friendly lighting, enhancing well-being, focus, and sleep quality.

Key Features of Tunable White Lighting:

✔ Adjustable Colour Temperature – Ranges from warm (relaxing) to cool (alertness-boosting).

✔ Flexible Intensity Control – Dimmable to suit different moods and tasks.

✔ Circadian Synchronisation – Aligns artificial lighting with natural body rhythms.

✔ Smart Integration – Can be controlled via AI; apps (e.g. smartwatch or Oura-type biometrics); or home automation systems.

Programmed tunable lighting is beginning to be deployed within commercial and healthcare interiors, where optimising light for human well-being is a priority. 

NB - RGBW lighting may also include tunable white light as well as full spectrum coloured light options. 

How Light Affects Our Bodies: The Science of Human-Centric Lighting

We’ve long understood that light helps us see, but we now understand how its influence extends far beyond vision. The human eye contains three types of photoreceptors (and if that’s news to you, it could be because number three was only discovered in 2003):

1. Rods – help us see in dim light.
2. Cones – allow us to perceive colour.
3. Intrinsically photosensitive retinal ganglion cells (ipRGCs) – regulate our circadian system by detecting blue light (wavelength ~480nm) and sending signals to the brain.

The ipRGCs control melatonin production, the hormone that dictates when we feel sleepy or alert. Exposure to blue-enriched light (such as daylight or cool LED lighting) suppresses melatonin, keeping us awake and focused. In contrast, warmer light in the evening signals the body to wind down, preparing us for restorative sleep.

When lighting is misaligned with our biological rhythms, whether due to excessive screen exposure, poor indoor lighting, or shift work, we experience circadian disruption, leading to fatigue, impaired cognitive function, and long-term health risks such as metabolic disorders and cardiovascular disease. This is where human-centric lighting is stepping in to create healthier environments.

The Link Between Sleep, Diet, and Longevity

Beyond lighting, sleep and diet are deeply intertwined. Poor sleep affects our hunger hormones, leading to increased cravings for high-calorie foods. A lack of rest results in:

• Increased Caloric Intake: Sleep deprivation affects the body’s regulation of ghrelin (hunger hormone) and leptin (satiety hormone), making people more prone to overeating.
• Cravings for Unhealthy Foods: Sleep-deprived individuals tend to prefer sugary, fatty, and processed foods, which further disrupt sleep quality.
• Higher Risk of Chronic Diseases: Poor sleep and an unhealthy diet contribute to obesity, diabetes, cardiovascular disease, and shorter lifespan.

Conversely, a diet rich in fibre, healthy fats, and balanced nutrients promotes deeper, more restorative sleep. This cyclical relationship between sleep and diet has significant implications for lifespan and healthspan, meaning that lighting that supports natural sleep patterns may also contribute to longer, healthier lives.

LEDs: The Game-Changer in Lighting Technology

Unlike traditional incandescent bulbs, LEDs are highly tunable - their colour temperature can be customised to flex throughout the day and evening, allowing for precise adjustments in intensity and colour temperature. LEDs can mimic the natural progression of daylight, shifting from bright, blue-rich morning/midday light, to warm, amber tones in the evening.

Why LEDs are Ideal for Human-Centric Lighting:

✔ Energy-efficient – uses up to 80% less energy than traditional lighting.

✔ Highly tunable – the same product can dynamically change colour temperature (2700K warm to 6500K daylight).

✔ Long lifespan – reduces waste and replacement costs.

✔ Integration with AI and IoT (the internet of things) – can be programmed to respond to time, weather, personal schedules, and biometrics.

This adaptability is key to personalised lighting environments, which could also be tailored not just for daily rhythms, but for personal chronotypes - whether your clients are larks, owls, or third-birds (somewhere in between). 

Tunable Lighting and Melanopic Lumens: The Next Frontier

John Cullen RGBW LED strip (above) combines tunable white light with a full spectrum of coloured light options

Tunable Lighting

Tunable lighting systems adjust colour temperature and intensity throughout the day, aligning with our biological needs. These systems are already being implemented in offices, hospitals, and schools to boost alertness, focus, and overall well-being - and in commercial aircraft, to encourage sleep and minimise jet lag. 

Case Study: Kaiser Permanente Medical Center, San Diego

The hospital integrates tunable LED lighting that follows the circadian rhythm. Cool blue light during the day keeps patients and staff alert, while warm lighting in the evening promotes relaxation and sleep. This approach enhances recovery and improves staff efficiency.

Melanopic Lumens: Measuring Light for Health

Traditional lighting is measured in lumens, which indicate brightness based on human vision. However, for circadian-friendly lighting, we need to measure how much light impacts our biological rhythms, this is where melanopic Lumens come in.

• High melanopic Lumens (cool white/blue light) → Increases alertness, great for workplaces and schools.
• Low melanopic Lumens (warm light) → Supports rest and relaxation, ideal for bedrooms and evening spaces.

Case Study: Arup’s Boston Office

Arup Group - designers, engineers, and consultants specialising in sustainable development and the built environment - has long been a pioneer of human-centric lighting, ever since the transition to LED made the concept possible.  

Their showcase Boston office uses circadian lighting principles with melanopic lighting adjustments. This system ensures employees receive daylight-mimicking brightness in the morning and warmer, softer tones in the afternoon and evening, improving focus and reducing fatigue.

AI and the Future of Adaptive Lighting

The next step in human-centric lighting will be AI-driven automation that optimises light for every individual and space.

Future AI Lighting Features:

✔ Smart home integration – Lighting adjusts based on voice commands and biometric data.

✔ Mood-responsive lighting – AI detects stress levels and adjusts light temperature accordingly.

✔ Geofencing – Lights adjust based on time zone and local sunrise/sunset.

✔ Sleep enhancement – AI syncs with smartwatches to ensure optimal lighting for sleep cycles.

Tunable Lighting Suppliers and Control Systems

Many companies now specialise in tunable white lighting solutions for commercial, and healthcare settings:

• Dextra: the largest privately-owned luminaire manufacturer in the UK, with a range of tunable white light products and control systems
• Lutron: High-performance dimming and tunable white solutions for commercial spaces.
• John Cullen: Tunable lighting products for circadian sympathetic lighting solutions

These innovative solutions ensure that human-centric lighting is no longer a luxury, it’s becoming a standard for well-being and longevity.

What can you do now: 

• Future-proof clients’ homes by specifying products that are tunable (e.g. Philips hue, or Govee), smart-compatible, and that can be integrated with AI-driven control systems like Lutron, Casaba, or KNX, allowing for their integration in the future as part of a controlled environment 
• Design using layered lighting - task, accent and ambient/general - that could be independently tuned for a more sophisticated experience 
• Zone lighting to accommodate personalised use, bearing in mind circadian rhythms, the function of different spaces, and their use by different occupants
• Allow space for the control hubs that may be installed in future 
• Specify warmer temperature lighting in bedrooms and relaxing spaces (below 3000K) to support better sleep 
• If you need a primer, my ‘Light Your Home’ course introduces the concepts of colour temperature, colour rendering, and other key considerations for the specification of residential lighting - I'm running a '50% off' with this blog post! 

Final Thoughts: The Dawn of Truly Personalised Lighting

Human-centric lighting is no longer just a concept, it’s here. With tunable LEDs, melanopic lighting strategies, and AI-powered customisation, the way we experience light is undergoing a revolution.

We are entering an era where lighting is no longer passive, it actively works to improve our lives, supporting sleep, metabolism, and even longevity. 

The future is bright, literally.

50% OFF - SPECIAL OFFER FOR MARCH: 

CLICK HERE: If you'd like a good foundation in lighting design, if you need a refresher on creating layered lighting, and would like to learn more about colour temperature, colour rendering, and zoning light, here's a link to my introductory course. 

This course starts at first principles and covers the basics of residential lighting design.