Bright Students – Dark Classrooms – Why Healthier School Lighting Matters

Imagine walking into a classroom where every student has the same textbooks, the same desks, and the same teacher—yet some students can’t absorb the material because the lighting isn’t right. That’s essentially what’s happening with melanopic light exposure in many classrooms today.  

The Blue-Sky Effect in the Classroom 

Light plays a crucial role in student focus, mood, attention, and overall cognitive performance—just think of how energized you feel on a bright day compared to a gloomy one. Natural daylight, rich in sky-blue wavelengths, helps regulate our internal clocks, boosting alertness and concentration. Perhaps nowhere is this effect more important than in the elementary classroom.  

Research shows that improved daylight exposure enhances academic performance: 

Most indoor environments, including classrooms, rely on electric lighting that often lacks sufficient biologically effective (melanopic) illumination. The CIE RP-46-23 standards recommend ≥250 melanopic equivalent daylight illuminance (m-EDI) during the day. While this is easily met outdoors, achieving it indoors with standard lighting or window exposure is challenging. Research shows that morning melanopic light exposure can immediately set circadian rhythms, but sustained exposure is crucial for maintaining mood, focus, and attention. Studies linking light exposure to academic performance suggest that even modern classrooms—with large windows and LED lighting—may not provide students with the healthy light they need. 

Could current classroom designs still be falling short in delivering optimal circadian lighting? If so, improving indoor lighting to better mimic natural daylight could be key for optimal student and teacher well-being and performance. 

The Reality of Classroom Lighting: A case study 

While windows and skylights provide natural daylight, their impact on melanopic light exposure is limited. The effectiveness of daylight drops significantly just a few feet from the window. This means that most students, even in well-lit classrooms, may not be receiving adequate light to support their circadian rhythms. 

To assess real-world classroom lighting conditions, we used WILMA (Wellness Illuminance Light Meter Array) to measure light spectra and levels in a modern Southern California school. The classroom had two large windows facing a bright courtyard, south-facing transom windows, and standard LED panel lighting. Measurements were taken at midday. 

 Findings revealed: 

The Melanopic Report Card: Is Your Classroom Making the Grade? 

Think of melanopic light like a daily dose of brain fuel—without enough of it, students may feel sluggish, unfocused, and not ready to learn. The study found that students seated in the middle of the classroom were particularly disadvantaged, receiving significantly lower melanopic exposure than their peers near windows or under direct lighting. In fact, 70% of students received less than 70% of the recommended melanopic light levels, with those in central seats dropping below 60% —a failing grade when it comes to supporting alertness and academic performance. 

 If we were to grade this classroom’s overall melanopic exposure, it would receive a “C”—a score no student would be happy to bring home, and certainly not one we should accept when it comes to our children’s health. Even classrooms with modern LED lighting and plenty of windows may not be delivering the right kind of light in the right amounts, leaving students in a circadian deficit, much like trying to take a test without having studied the material. 

 This finding challenges the way we think about classroom design. Could something as simple as seating arrangements influence student wellness and performance more than we realize? Just as a well-organized seating chart can improve participation and collaboration, a thoughtfully lit classroom can optimize focus and learning. Instead of relying on chance exposure to healthy light, schools should consider circadian lighting solutions designed to deliver the right spectrum of light to all areas of the classroom. 

 If we want students to ace their studies, we need to ensure their classrooms get an A+ in lighting design. The future of learning isn’t just about textbooks and technology, it’s about creating an environment that truly supports cognitive function, mood, alertness, and well-being. It’s time to rethink classroom lighting so every student has the best chance to shine! 

Literature cited 

Baloch RM, Nichole Maesano C, Christoffersen J, Mandin C, Csobod E, de Oliveira Fernandes E, Annesi-Maesano I, Sinphonie Consortium. Daylight and school performance in European schoolchildren. International journal of environmental research and public health. 2021 Jan;18(1):258. 

Choi K, Shin C, Kim T, Chung HJ, Suk HJ. Awakening effects of blue-enriched morning light exposure on university students’ physiological and subjective responses. Scientific reports. 2019 Jan 23;9(1):345. 

Grant LK, Kent BA, Mayer MD, Stickgold R, Lockley SW, Rahman SA. Daytime exposure to short wavelength-enriched light improves cognitive performance in sleep-restricted college-aged adults. Frontiers in neurology. 2021 Feb 22;12:624217. 

Heschong L. 1999. Daylighting in Schools: An Investigation into the Relationship between Daylighting and Human Performance. Detailed Report. 

Keis O, Helbig H, Streb J, Hille K. Influence of blue-enriched classroom lighting on students׳ cognitive performance. Trends in Neuroscience and Education. 2014 Sep 1;3(3-4):86-92.