From energy savings to human health: why “good light” matters more than ever

A summary of the article by Jan Denneman and Dave Hollingsbee, published in Arc, a magazine for architects and interior designers.

For years, the lighting industry has focused on three key goals: functionality, design, and sustainability. We have made remarkable progress in energy efficiency, circular manufacturing, and smarter lighting controls. But there is a fourth dimension that deserves equal attention: sleep, human health and performance.

Photo by copernico on Unsplash

One of the most compelling arguments comes from the “3-30-300 rule,” which highlights how organisations typically spend around €3 on utilities, €30 on space, and €300 on people for every square foot of building space. While lighting is often evaluated based on energy savings, the greatest financial impact may come from its influence on employees. Even a 1% improvement in productivity or reduction in absenteeism can save hundreds of thousands of euros annually, far exceeding typical lighting energy costs.

Recent discoveries in chronobiology support this perspective. Researchers have shown that light does much more than enable vision; it regulates our internal body clock, sleep quality, alertness, and overall health. Modern indoor lifestyles often expose us to too little daylight during the day and too much artificial light in the evening, disrupting natural circadian rhythms. The result can be poorer sleep, reduced concentration, and lower workplace performance.

We introduced the concept of a “light diet,” comparing light exposure to nutrition. Just as a healthy diet supports physical wellbeing, the quality, intensity, and timing of light exposure play a critical role in human health. This means lighting should no longer be considered background infrastructure, but an active contributor to wellbeing and productivity.

We advocate for greater access to natural daylight, and for electric lighting that compensates the lack of natural daylight. We want to encourages architects, designers, developers, and policymakers to move beyond compliance and energy metrics and instead focus on measurable human outcomes.

Ultimately, the message is clear: sustainability is not only about reducing energy consumption. Truly sustainable buildings must also support the health, resilience, and performance of the people who use them. The challenge facing the industry is no longer whether healthier lighting is possible, it is about entering this new chapter of the lighting industry.

Read the full article here