Human-Centric Lighting

In the evolving landscape of commercial building design and management, lighting has transcended its basic function of illumination to become a powerful tool for enhancing human experience. Human-centric lighting (HCL) represents a paradigm shift in how we approach lighting design, focusing on the profound impact that light has on our biology, psychology, and overall well-being. For businesses looking to optimize their workspaces, understanding and implementing human-centric lighting strategies can lead to significant improvements in employee productivity, satisfaction, and health.

The Science of Light and Human Biology

To appreciate the value of human-centric lighting, we must first understand the fundamental relationship between light and human physiology.

Circadian Rhythms Explained

Our bodies operate on a roughly 24-hour cycle known as the circadian rhythm, an internal clock that regulates numerous physiological processes including sleep-wake cycles, hormone production, body temperature, and cognitive functions. This biological timing system evolved in response to the natural light-dark cycle of our planet.

The suprachiasmatic nucleus (SCN), located in the hypothalamus, serves as our master circadian clock. This tiny cluster of neurons receives direct input from specialized photoreceptors in our eyes called intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells are particularly sensitive to blue-wavelength light (around 480nm) and signal the SCN about environmental light conditions.

When exposed to bright, blue-rich light (similar to morning daylight), the SCN suppresses the production of melatonin (the sleep hormone) and increases cortisol (the alertness hormone), promoting wakefulness and alertness. Conversely, as light dims and shifts to warmer tones in the evening, melatonin production increases, preparing the body for rest.

How Light Affects Sleep-Wake Cycles

The quality, intensity, spectrum, and timing of light exposure directly influence our sleep-wake patterns. Exposure to bright, blue-rich light during the day helps maintain a healthy circadian rhythm, while inappropriate light exposure (particularly blue light) in the evening can disrupt this system.

Research published in the Special Issue 'Cognitive and Emotional Effects of Sleep Deprivation' demonstrates that individuals working in environments with inadequate daytime light exposure show disrupted melatonin patterns and report poorer sleep quality. Conversely, workers in environments with robust daytime light exposure show more consistent circadian rhythms and better sleep outcomes. *16

Impact of Light on Mood, Alertness, and Cognitive Function

Light's influence extends beyond sleep regulation to directly affect mood, alertness, and cognitive performance:

• Mood Regulation: Light therapy has been established as an effective treatment for seasonal affective disorder (SAD) and has shown benefits for non-seasonal depression. Studies indicate that bright light exposure increases serotonin levels, a neurotransmitter associated with mood elevation.

• Alertness and Attention: Research from Harvard Medical School*1 demonstrates that blue-enriched light improves subjective alertness, reduces reaction times, and enhances attention compared to lighting with minimal blue content.

• Cognitive Performance: A landmark study published in Scandinavian Journal of Work, Environment & Health*2 found that workers under optimized lighting conditions performed 10-15% better on tests of working memory, processing speed, and cognitive flexibility compared to those under standard office lighting.

These biological mechanisms explain why lighting conditions in commercial environments can significantly impact occupant performance and well-being.

Key Components of Human-Centric Lighting

Human-centric lighting systems are designed to support natural circadian rhythms while meeting the visual and emotional needs of occupants. Several key components distinguish HCL from conventional lighting approaches.

Color Temperature Control

Color temperature, measured in Kelvin (K), describes the apparent color of light emitted by a source. Lower Kelvin values (2700-3000K) produce "warmer" light with more yellow and red content, while higher values (5000K+) create "cooler" light with increased blue content.

Human-centric lighting systems incorporate tunable white technology that allows for dynamic adjustment of color temperature throughout the day:

• Morning (8:00-10:00 AM): Higher color temperatures (5000-6500K) with increased intensity to stimulate alertness and suppress melatonin

• Midday (10:00 AM-2:00 PM): Maintained high color temperature (4000-5000K) with maximum intensity

• Afternoon (2:00-5:00 PM): Gradual reduction in color temperature (3500-4000K) and slight decrease in intensity

• Evening (5:00 PM onward): Further reduction to warmer color temperatures (2700-3000K) with diminished intensity to allow natural melatonin production

This dynamic approach mimics the natural progression of daylight, supporting healthy circadian entrainment.

Intensity and Brightness Considerations

Light intensity, measured in lux or footcandles, is equally important in human-centric lighting design. Appropriate intensity levels vary by space function and time of day:

• Task Areas: 28-46 fc, for standard office tasks, with the ability to increase to 70+ fc for detailed work

• Circulation Areas: 14-28 fc, with potential for dynamic adjustment

• Collaborative Spaces: 28-27 fc, with flexibility for different activities

• Break Areas: Variable 14-28 fc, with warmer color temperatures

Human-centric systems incorporate the ability to adjust intensity based on both scheduled patterns and immediate needs, often through scene-setting capabilities that allow users to select appropriate lighting for different activities.

Dynamic Lighting Systems

True human-centric lighting is inherently dynamic, changing throughout the day to support biological needs while accommodating functional requirements. This dynamism is achieved through:

• Programmable Time-Based Control: Automatic adjustments to color temperature and intensity following predetermined schedules

• Occupancy-Based Adaptation: Modifications based on space usage patterns

• Task-Tuning: Optimization for specific activities and visual tasks

• Personal Control Options: User interfaces that allow individual adjustment within biologically appropriate parameters

Advanced systems may incorporate artificial intelligence to learn occupancy patterns and preferences, continuously optimizing lighting conditions while maintaining circadian benefits.

Integration with Natural Light

Daylighting, the strategic use of natural light, is a fundamental component of human-centric lighting strategies. Effective integration includes:

• Daylight Harvesting: Automatic adjustment of electric lighting in response to available daylight

• Glare Management: Dynamic shading systems or electrochromic glazing that controls daylight without blocking views

• Light Distribution: Architectural elements that help daylight penetrate deeper into spaces

• Supplemental Electric Lighting: Artificial sources that complement natural light in terms of spectrum and distribution

Research from the Well Living Lab (a Delos and Mayo Clinic collaboration)*3 indicates that spaces with integrated natural and artificial lighting strategies show superior outcomes for occupant well-being compared to those relying predominantly on either source alone.

Benefits for Commercial Spaces

The implementation of human-centric lighting in commercial environments yields measurable benefits across multiple dimensions.

Improved Employee Productivity

Implementing human-centric lighting has been associated with notable enhancements in employee productivity. For instance, a study conducted at the headquarters of CBRE in Amsterdam introduced a time-controlled lighting system that varied color temperature and intensity throughout the day. This dynamic lighting led to an 18% perceived improvement in work performance and a 12% increase in work accuracy among employees.*4

These productivity improvements stem from enhanced visual comfort, reduced eye strain, improved cognitive function, and better alignment of alertness with work demands.

Enhanced Focus and Cognitive Performance

Human-centric lighting directly impacts cognitive capabilities:

• Dynamic light lead to employees to have to put in less effort to concentrate, with lower levels of tension after completing cognitive tasks. *5

• Office workers reported feeling energetic, more vital and alert when lighting supports healthy circadian function, according to research from the Lighting Research Center at Rensselaer Polytechnic Institute. *6

• A 2024 study published in 'Sleep' demonstrated that workers exposed to circadian-supportive lighting showed improved executive function, faster reaction speed, with ~50% fewer lapses.*7

These cognitive benefits are particularly valuable for knowledge workers whose output depends directly on mental performance.

Reduced Absenteeism and Health Complaints

Proper lighting contributes to overall health and well-being, reducing absence and health-related complaints: Implementing human-centric lighting in healthcare settings has been associated with improved mood and behavior among residents. *8 Additionally, exposure to dynamic lighting has been linked to better sleep quality and reduced fatigue, which can decrease fatigue-related absences.

These health benefits translate directly to operational savings through reduced absenteeism and presenteeism (reduced productivity due to working while unwell).

Better Mood and Workplace Satisfaction

The psychological benefits of human-centric lighting contribute significantly to workplace satisfaction:

• A healthy circadian rhythm can indirectly improve alertness, cognitive functioning, and mood. Moreover, recent findings suggest that light can also have a direct effect on the neural pathways that act on mood and cognition. *9

• An extensive study into happiness and productivity has found that workers are 13% more productive when happy. *10

  
  

These satisfaction improvements contribute to organizational culture and can reduce costly employee turnover.

The Healthy Offices project, measured the effects of changes in work surroundings at CBRE Headquarters and employee health over a period of seven months.

• In an objective experiment, accuracy improved 12%

• Total work performance increased by 18%

• 71% reported having more energy

• 76% reported feeling happier

• 50% reported being healthier *4

  
  

Applications Across Different Industries

Human-centric lighting principles apply across various commercial environments, with implementation strategies tailored to specific needs.

Office Environments

In office settings, human-centric lighting supports knowledge work and collaboration:

• Open Offices: Layer ambient lighting with adjustable task lighting, incorporate daylight harvesting, and provide zones with different lighting characteristics for various activities

• Private Offices: Enable personal control within circadian-appropriate parameters

• Meeting Rooms: Implement scene settings for different meeting types (presentations, discussions, video conferences)

• Break Areas: Create relaxing environments with warmer color temperatures and lower intensity

Case Example: An open-plan office at Istanbul Technical University used a wireless automation system. The study suggests that individualized, user-controllable lighting systems can improve office workers' satisfaction and cognitive performance, proposing the integration of energy-efficient, human-centered lighting systems in open-plan offices. *11

Healthcare Facilities

Healthcare environments benefit particularly from human-centric approaches:

• Patient Rooms: Implement dynamic lighting that supports natural circadian rhythms to improve sleep and recovery

• Staff Areas: Provide alertness-supporting lighting for night shift workers while minimizing circadian disruption

• Treatment Areas: Ensure excellent color rendering for accurate assessment while maintaining comfortable conditions

• Waiting Areas: Create calming environments that reduce stress and anxiety

Case Example: The Stroke Unit at Rigshospitalet Glostrup found that patients were 30% less tired and 49% less depressed when they are discharged than patients from the neighboring ward, which had standard indoor lighting. The effect was the same as if the patients had taken antidepressant medication. *12

Educational Institutions

Schools and universities can enhance learning environments through human-centric lighting:

• Classrooms: Implement dynamic lighting that supports alertness during instruction while allowing adjustment for different activities

• Libraries: Provide appropriate task lighting with minimal glare for reading

• Laboratories: Ensure excellent color rendering and appropriate light levels for detailed work

• Common Areas: Create inviting spaces with lighting that supports social interaction

Case Example: two fourth-grade classrooms of 27 students each. One received LED lights with three CCT options, the other had fluorescent lighting. there were no significant differences between pretest and posttest in the control group, However 35K increased recess activity, and 65k was perceived as the appropriate lighting for learning. In fact the results of the arithmetic activity indicated that a larger percentage of correct answers occurred with 6500K. *13

Retail Spaces

Retail environments can leverage human-centric principles while supporting merchandising goals:

• Sales Floors: Balance circadian-supportive general lighting with accent lighting that enhances merchandise

• Fitting Rooms: Provide lighting scenarios that accurately represent different environments (daylight, evening, office)

• Staff Areas: Implement proper task lighting and circadian support for employee well-being

• Checkout Areas: Ensure appropriate light levels for transaction tasks while maintaining an inviting atmosphere

Case Example: Two supermarkets were studied for 10 months under different lighting conditions. The results show that under HCL conditions sales rose in some sections by up to 28% in comparison to the reference store during the study period. *14

Hospitality Settings

Hotels and restaurants can enhance guest experience through thoughtful lighting:

• Guest Rooms: Provide intuitive control over lighting scenes that support different activities and times of day

• Lobbies and Public Spaces: Create dynamic environments that transition from energizing daytime settings to relaxing evening atmospheres

• Dining Areas: Implement warm, inviting lighting that enhances food presentation while supporting social interaction

• Conference Facilities: Provide flexible lighting for different event types and times of day

Case Example: A luxury hotel in New York installed a smart lighting system with human-centric lighting in guest rooms. This enhanced guest comfort and satisfaction resulted in a 20% increase in positive reviews. *15

Measuring Success

Evaluating the effectiveness of human-centric lighting implementations requires a multifaceted approach.

Key Performance Indicators

Establish quantitative metrics to assess impact:

• Energy Usage: Compare lighting energy consumption before and after implementation

• Productivity Metrics: Track task completion rates, error rates, or other performance indicators

• Absenteeism: Monitor changes in sick days and unplanned absences

• Space Utilization: Assess whether lighting changes affect how spaces are used

• Maintenance Requirements: Track frequency and cost of lighting-related maintenance

These metrics provide objective evidence of system performance and return on investment.

Employee Feedback Mechanisms

Gather qualitative input through structured feedback channels:

• Pre/Post Surveys: Conduct standardized questionnaires before and after implementation

• Focus Groups: Hold discussions with representative user groups

• Digital Feedback Tools: Implement apps or other digital means for ongoing feedback

• Observational Studies: Conduct systematic observations of how lighting affects behavior

• Exit Interviews: Include lighting quality in workplace exit interviews

This feedback helps identify subjective improvements and areas needing adjustment.

Productivity Metrics

Depending on the organization, specific productivity measures might include:

• Knowledge Work: Projects completed, deadlines met, quality assessments

• Customer Service: Call handling times, resolution rates, customer satisfaction

• Sales Environments: Conversion rates, average transaction values, return rates

• Healthcare: Patient recovery times, medication errors, staff efficiency

• Education: Test scores, attendance rates, student engagement

These metrics should be tracked over sufficient time to account for seasonal variations and novelty effects.

Energy Efficiency Considerations

While human-centric lighting prioritizes human outcomes, energy performance remains important:

• Consumption Patterns: Monitor energy use across different times and seasons

• Demand Response Capability: Assess how the system can adjust during peak demand periods

• Control Effectiveness: Evaluate how occupancy sensing, daylight harvesting, and scheduling affect energy use

• Comparative Analysis: Benchmark energy performance against industry standards and previous systems

The most successful implementations balance human benefits with responsible energy use.

Conclusion

Human-centric lighting represents a significant advancement in our understanding of how the built environment affects human health, well-being, and performance. By designing lighting systems that support our biological needs while meeting functional requirements, commercial spaces can become more productive, healthier, and more satisfying environments.

The science is clear: light profoundly affects our physiology and psychology. The technology is available: tunable, controllable LED systems can deliver appropriate light at the right time. The business case is compelling: improvements in productivity, health, and satisfaction provide tangible returns on investment.

As we look to the future, human-centric lighting will likely become the standard approach rather than a premium option. Organizations that implement these principles now not only gain immediate benefits but position themselves at the forefront of workplace design and employee wellness.

Future of Human-Centric Lighting

The field continues to evolve, with emerging trends including:

• Personalized Lighting: Systems that adapt to individual preferences and chronotypes

• Wearable Integration: Lighting that responds to data from personal health devices

• Advanced Controls: Artificial intelligence that continuously optimizes lighting based on occupant feedback and performance data

• Health Monitoring: Lighting systems that detect and respond to signs of occupant stress or fatigue

• Expanded Spectral Control: More sophisticated manipulation of non-visual spectral components

These advancements will further enhance the benefits of human-centric lighting in commercial environments.

Getting Started with HCL in Your Facility

For organizations considering human-centric lighting, we recommend a phased approach:

1. Assessment: Contact Lights There to evaluate your current lighting conditions and identify specific improvement opportunities

2. Pilot Implementation: Start with a limited area to demonstrate benefits and refine approaches

3. Measurement: Establish clear metrics to evaluate success

4. Education: Ensure occupants understand the system and its benefits

5. Expansion: Apply lessons learned to broader implementation

   
   

Lights There specializes in human-centric lighting design and implementation for commercial spaces. Our team combines lighting expertise with a deep understanding of human factors to create environments that enhance well-being and performance. Contact us for a consultation to explore how human-centric lighting can transform your facility.

(702) 379-5396 Solutions@LightsThere.com

Citations

*1 https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side

*2 Rasouli Kahaki, Zeinab et al. “Subjective and objective survey of office lighting: effects on alertness, comfort, satisfaction, and safety.” La Medicina del lavoro vol. 113,3 e2022024. 28 Jun. 2022, doi:10.23749/mdl.v113i3.12371

*3 Anja Jamrozik, Nicholas Clements, Syed Shabih Hasan, Jie Zhao, Rongpeng Zhang, Carolina Campanella, Vivian Loftness, Paige Porter, Shaun Ly, Selena Wang, Brent Bauer,

Access to daylight and view in an office improves cognitive performance and satisfaction and reduces eyestrain: A controlled crossover study, Building and Environment, Volume 165, 2019,

106379, ISSN 0360-1323, https://doi.org/10.1016/j.buildenv.2019.106379 (https://www.sciencedirect.com/science/article/pii/S036013231930589X)

*4 Original link: luxreview.com/2017/10/30/human-centric-office-lighting-boosts-productivity  Link to a copy of the original: www.ledlighttech.com/blog/2019/1/21/human-centric-office-lighting-boosts-productivity

*5 Schöllhorn, Isabel et al. “Effects of nature-adapted lighting solutions ("Virtual Sky") on subjective and objective correlates of sleepiness, well-being, visual and cognitive performance at the workplace.” PloS one vol. 18,8 e0288690. 3 Aug. 2023, doi:10.1371/journal.pone.0288690

*6 https://www.lrc.rpi.edu/programs/lightHealth/pdf/Figueiro_IESConference_Aug2017.pdf

*7 Hannah Scott, Alisha Guyett, Jack Manners, Nicole Stuart, Eva Kemps, Barbara Toson, Nicole Lovato, Andrew Vakulin, Leon Lack, Siobhan Banks, Jillian Dorrian, Robert Adams, Danny J Eckert, Peter Catcheside, Circadian-informed lighting improves vigilance, sleep, and subjective sleepiness during simulated night-shift work, Sleep, Volume 47, Issue 11, November 2024, zsae173, https://doi.org/10.1093/sleep/zsae173

*8 Böhmer, M N et al. “Light up: an intervention study of the effect of environmental dynamic lighting on sleep-wake rhythm, mood and behaviour in older adults with intellectual disabilities.” Journal of intellectual disability research : JIDR vol. 66,10 (2022): 756-781. doi:10.1111/jir.12969

*9 (Fernandez et al., 2018;).

*10 Bellet, Clement and De Neve, Jan-Emmanuel and Ward, George, Does Employee Happiness have an Impact on Productivity? (October 14, 2019). Saïd Business School WP 2019-13, Available at SSRN: https://ssrn.com/abstract=3470734 or http://dx.doi.org/10.2139/ssrn.3470734

*11 S. Aliparast and S. Onaygil, "Case Study on the Effect of a Human-Centered Smart Lighting System on the Comfort Preferences of Office Workers with Different CCTs," 2024 IEEE Sustainable Smart Lighting World Conference & Expo (LS24), Eindhoven, Netherlands, 2024, pp. 1-4, doi: 10.1109/LS2463127.2024.10881600.

*12 Damsgaard, Ditte. “Amber Nights Make Patients Less Depressed.” Ugeskriftet.Dk, The Journal of Doctors, 31 Aug. 2018, ugeskriftet.dk/nyhed/ravfarvede-naetter-gor-patienter-mindre-deprimerede.

*13 Choi, Kyungah & Suk, Hyeon-Jeong. (2016). Dynamic lighting system for the learning environment: performance of elementary students. Optics Express. 24. A907-A916. 10.1364/OE.24.00A907. https://opg.optica.org/oe/fulltext.cfm?uri=oe-24-10-A907&id=340246

*14 “Oktalite | Human Centric Lighting.” Oktalite.com, 2023, www.oktalite.com/en/applications/innovations/hcl/#c2017.

*15 ANC. “Exploring the Future of Hospitality Lighting Technologies - ANC Lighting.” Iluminación ANC, 9 Jan. 2025, www.anclighting.com/es/exploring-the-future-of-hospitality-lighting-technologies/.

*16 Boubekri, Mohamed et al. “The Impact of Optimized Daylight and Views on the Sleep Duration and Cognitive Performance of Office Workers.” International journal of environmental research and public health vol. 17,9 3219. 6 May. 2020, doi:10.3390/ijerph17093219