What Is Human Centric Lighting? Your Essential Guide to HCL
Posted March 3, 2026 by Natalie
We spend around 90% of our time indoors under artificial lights, yet our bodies are still wired for natural daylight. A lack of sunlight, and its visual and non-visual benefits, can be a nightmare for our health. So what can we do? Step forward human centric lighting (HCL) - a design approach that combines natural daylight with dynamic electric light to support human health, mood and productivity. We’re receiving growing interest in this emerging concept, so here's an essential overview to explain how HCL works, where it's used and why it matters.
Table of Contents:
Human Centric Lighting: A Definition
HCL is a human-focused lighting design approach, which incorporates daylight-mimicking technology to support our psychological and physiological needs.
HCL (also known as circadian, wellness, biodynamic or integrative lighting) is not a product – it’s a combination of insightful design and smart technology.
Key features of HCL:
- Blends dynamic electric light with natural daylight
- Supports mood, sleep, energy & productivity
- Focuses on light’s beneficial effects on humans
Contemporary kitchen light colour & intensity matched to the time of day.
Electric light was originally designed for indoor spaces, not for the people who use them. In contrast, although HCL can’t replace daylight entirely increasing research shows that it can replicate some of its positive effects on our biology and wellbeing. Hooray!
The Benefits of Human Centric Lighting
Scientific research continues to provide evidence of the many positive effects of HCL applications in different environments, including offices, classrooms and hospitals.
Increased Productivity & Focus
HCL can be programmed to meet specific needs, e.g.:
- Enhance alertness in the workplace
- Calm students in schools
- Support shift workers during irregular working hours
Better Quality Sleep
HCL improves natural sleep cycles which:
- Promotes recovery in hospital – patients in this study slept an average of 66 minutes longer and reported more waking alertness than patients in the control group
- Helps with traveller jet lag in hotels
- Increases our resilience against medical conditions such as cardiovascular issues and diabetes
Enhanced Health & Wellbeing
Human centric lighting is better aligned with our physiology and provides:
- Better visual comfort
- Less eye strain & headaches
- Reduced cases of myopia (short-sightedness) in children
Improved Mood
HCL encourages better mood regulation in those affected by conditions such as:
- Mental health issues
- Seasonal Affective Disorder (SAD)
- Dementia
HCL promotes better sleep, mood regulation, visual comfort & productivity.
HCL is proving to be beneficial to both individuals and institutions – feeling good and well-rested helps us perform better at our jobs, and even recover faster from illness and injury. So how exactly does HCL work?
How Does Human Centric Lighting Work?
In order to optimally regulate our hormones and promote our general wellbeing, humans need dynamic light that imitates the light we see in nature - ranging from dappled sunlight, up to full midday sun, all the way down to glowing evening campfire.
The Circadian Rhythm
The circadian rhythm is our internal 24-hour biological clock which influences many physiological processes within our bodies. One of these processes is our sleep-wake cycle, which the circadian rhythm controls by stimulating the production of melatonin (sleep hormone) and cortisol (alertness hormone). Light is the most important factor in regulating a healthy, balanced circadian rhythm.
Dynamic Light vs. Static Light
The traditional artificial light that we use is static, meaning its colour and brightness don’t vary in the same way that natural sunlight does.
Daylight is always changing due to factors such as:
- The day-night cycle
- Weather patterns
- Seasonal variation
- Global latitude
Traditional electric light disrupts our natural sleep-wake cycle whereas dynamic HCL works in harmony with our biological rhythms. HCL uses dynamic light which mimics natural fluctuations by seamlessly changing the colour and intensity of the light that fills our indoor spaces, through a cunning combination of clever design and cutting-edge technology.
Lighting should be designed for people, not just spaces. Human Centric Lighting recognises light as a biological driver, shaping how we feel, function and recover every day.
- Jack, Darklight Design Sales Executive
How to Create a Human Centric Lighting System
An HCL scheme consists of two main components: human-centred design and smart IoT technology.
Human-Focused Design
Human centric lighting design focuses on the impact that an interior environment has on its inhabitants, as opposed to purely considering visibility.
Key considerations of HCL design include:
- Lighting design fundamentals - layers of light that work together
- The individual environment – where it is, who uses it, how & when they use it
- Natural light sources – daylight harvesting & integration with dynamic artificial light
- Surface lighting – for both vertical and horizontal planes
- Visual comfort & glare - measuring how much light reaches the eye, not just the desk
Smart Technology
A biodynamic lighting system combines dynamic LEDs, intelligent sensors and automated control - so you don’t have to lift a finger.
Tunable LED Lighting
State-of-the-art tunable LED bulbs can replicate natural daylight by varying the colour of white light that they produce. Standard LED lighting is static and, therefore, unable to perform this function.
Tunable LEDs have the flexibility to change their:
Light Colour
- Cool white light (5000–7000K) – mimics bright daylight, boosts alertness
- Warm white light (2700–3500K) - mimics dawn & dusk, supports relaxation & sleep
- A mix of different colour bulbs in each fixture allows the colour to change along a spectrum of white, from cool to warm.
Light Intensity
- The intensity of each tunable luminaire can be brightened or dimmed
- The brightness of environmental light and the duration of our exposure to it both affect our biological responses
- Research recommends our eyes are exposed to 250 melanopic lux for 30 mins in the morning to regulate our sleep cycles effectively
To learn more about these adaptable LEDs, read our overview of tunable white lighting.
Table: Cool White vs Warm White Light.
| Colour Temperature | Effect | Best Time of Day | Typical Use |
|---|---|---|---|
| 5000–7000K (Cool White) |
Boosts alertness & focus; mimics bright daylight | Morning to midday | Offices, schools, task-focused spaces |
| 2700–3500K (Warm White) |
Supports relaxation & sleep; mimics dawn & dusk | Late afternoon & evening | Homes, hotels, wind-down spaces |
Networked sensors monitor each space within an HCL lighting scheme and feedback data to an intelligent control system.
Types of networked sensors in a human centric lighting scheme include:
- Ambient Light / Photometric Sensor - monitors the levels of natural daylight in a space to allow the colour or brightness of electric light in the room to be adjusted as required.
- Occupancy Detector – highly-sensitive presence detectors allow lights to be switched off when a space is unoccupied, or to activate the lighting scheme when someone enters a room.
- Real-Time Clock (RTC) & Astronomical Clock – supports circadian rhythms by allowing the colour and intensity of electric light to synchronise with the real-world day/night cycle and seasonal variations.
Automated Control System
A pre-programmed control system receives data from the sensors and uses this information to automatically adjust the illumination in individual areas to match the lighting scheme specified by the client.
Benefits of smart lighting control systems:
- Conserve electricity & save money
- Wireless options minimise the need for renovation & re-decoration
- Pre-programmed but can be manually overridden using smartphones & tablets
- Effortless lighting schemes that boost health, focus & comfort.
Animation of a dynamic Human Centric lighting system in a contemporary kitchen throughout the day.
The Future of Human Centric Lighting
Human Centric Lighting represents a move towards healthier, more human-focused architectural design - HCL is recognised by RIBA and CIE, and is included in the IWBI’s WELL Building Standard criteria. Research, technology and best practices are still evolving, so it’s essential for HCL systems to remain flexible in order to adapt to any necessary changes. The future of HCL looks healthy, because when lighting supports your biology life feels just that little bit brighter.
FAQs
Q. Is human centric lighting the same as circadian lighting?
HCL and circadian lighting are closely related, and sometimes used interchangeably, but they are not the same. HCL is an ‘umbrella term’ of which circadian lighting is a specific subset. While circadian lighting uses biodynamic lighting technology to strictly mimic the natural 24-hour light-dark cycle, HCL is a broader design approach that also includes glare reduction, mood enhancement and overall safety - as well as recognising that it is not always practical in our modern world to synchronise our circadian rhythms exclusively with daylight.
Q. Do I need special products to create an HCL system, or can I retrofit existing lighting?
HCL requires tunable LED lighting as well as control systems which are capable of automatically adjusting colour temperature and intensity throughout the day. Standard static fixtures cannot replicate this, so most HCL installations involve upgrading to tunable white products rather than adapting existing fixed-output lighting.
Q. Is there real scientific evidence that HCL works?
Yes. Research has linked HCL to measurable outcomes, including improved patient recovery in hospitals, better sleep regulation and enhanced alertness.
Q. Is human centric lighting only for offices and hospitals, or is it relevant for homes too?
While much of the current research and installation focus is on commercial, healthcare and education settings, the underlying biological principles apply to any indoor space. Homes can even benefit from simple circadian lighting approaches, such as warmer lighting in the evening and cooler, brighter light in the morning.
Q. What colour temperature should I use for human centric lighting?
Cool white light (5000–7000K) is used earlier in the day to boost alertness, while warm white light (2700–3500K) is used in the evening to support relaxation and sleep. An effective HCL system transitions gradually between these ranges rather than switching abruptly.
So what's next?
- Read more posts on Human Centric Lighting
- Discover our Lighting For Health range - a curated collection designed to support Human Centric Lighting projects.
- Ready to start your HCL project? Or still have questions?
Contact us on 01189 882294 or [email protected]
We're happy to help :)
