by Gabriel Hurley

Until recently, little attention was paid to the lighting of schools and how that lighting might affect students. Marshall Davidson notes that in the mid 1700s, although the United States experienced a great increase in schools, colleges, and libraries, “even the best-read people remained sparing with candlelight.” A 1928 public health report from the United States included a survey of lighting standards in schools. The report found that “there is a great divergence among the different States and cities of the Union as to their requirements for natural and artificial lighting of school rooms. ” In the past three decades, however, environmental psychologists have paid an increasing amount of attention on how lighting might be improved in order to help students. This essay will discuss some of the studies in this area and suggest some practical steps that might be taken based on the results.

Early Experiments with Light and Colour

One of the earliest studies into the effect of lighting on students was conducted by Harry Wohlfarth (1986)⁠ for the Alberta Department of Education. Conducted in four elementary schools in the Wetaskiwin school district, the study was primarily intended to find connections between classroom colours and various progress indicators. These indicators included: student mental ability and achievement, attitude toward school subjects, misbehaviour, absences from illness, refractive eye problems, blood pressure, and mood variations. In the study, one school was used as a control group, one school had the classrooms painted with a “psychodynamic colour scheme”, one school incorporated the new colours as well as full-spectrum lighting1, and one school only incorporated the full-spectrum lighting. The study found that the light and colour changes had no effect on student performance in Metropolitan Achievement, Otis Lennon, Lorge-Thorndike IQ, or CTBS tests. Attitudes toward school were not affected either.

Nevertheless, the study was useful because it prompted a number of new experiments. Because it was the first of its kind and asked a large number of questions, it was used as a reference point for studies that were more precise. There were some positive findings: warm colours were found to increase blood pressure in students, full-spectrum lighting was found to improve the moods of students, and one class that was exposed ultraviolet radiation experienced fewer dental caries (ie. cavities). The last two findings suggested that small amounts of UV radiation could benefit students.

Focusing in on Light Sources

In order to test that hypothesis, another study was conducted (Hathaway, John , Gordon, & Dennis, 1992)⁠ to test the specific effects of full-spectrum and ultraviolet lights. The study took place two school years in the Grade 4 classrooms of four schools: one with high pressure sodium vapour (HPSV)2 lights, one with typical florescent lights, one with full-spectrum lights, and two with UV-enhanced full-spectrum lights. All of the rooms had approximately the same brightness. Once again, full-spectrum light (with or without UV supplements) did not increase student performance in standardised tests over traditional fluorescent lights. However, after two school years, the students exposed to HPSV lights had fallen behind the other students by about 6.4 months. Ultraviolet light was also beneficial to the students’ dental health; the UV class experienced 0.75 fewer dental caries per child per year.

Here Comes the Sun

Hathaway’s study was not conclusive. The researchers did not consider that windows might affect the amount of full-spectrum light that students receive. Lisa Heschong, Rojer L. Wright, and Stacia Okura (2002)⁠ attempted to correct this error. Using a larger sample space, they analysed the performance of students from three different school districts in three different US States. In all, the study covered 2000 classrooms. In order to correct the errors of previous experiments, they isolated the variables of window size, daylight exposure, and skylight type by assigning a numerical scale to each. Artificial lighting was found to be constant in all the schools. The study specifically included classes with skylights in order to see if academic performance is influenced solely by light. Windows, they argued, might confer other effects because they provide a view and have cultural meaning. Skylights, on the other hand do not. Data gathered from the Capistrano school district (24 schools were analysed) was the most significant. Students in that district take standardised tests3 at the beginning and end of the school year, so the researchers could use the data to determine if natural lighting was actually correlated with an improvement in performance.

Bright daylight, large windows, and skylights that diffused light throughout the room were associated with high achievement. Students in the classrooms with the highest window code improved 15% - 23% faster on Capistrano Core Level Tests than classrooms with the lowest window code. In classrooms with the highest daylight codes, students improved 20% - 26% faster than students in classrooms with the lowest daylight codes. Skylights that diffused light throughout the classroom were correlated with a 19% - 20% improvement in test scores over classrooms with no skylights. In the other two districts, standardised tests were only performed at the end of the year. Nevertheless, absolute test scores were higher in classrooms with bright daylight, large windows, or diffusing skylights.

Heschong, Wright, and Okura were careful to point out that while their study found a strong correlation between daylight and academic achievement, that did not necessarily mean that there was causation. However, they did suggest that student and teacher performance and morale might be improved due to “Mental stimulation from varying lighting conditions, calming effect of a connection with the natural world, greater mental alertness due to circadian biochemical responses to daylight, [and] better memory retention due to one or more of the above processes.

Practical Applications

If natural sunlight is beneficial to students, how can a teacher take advantage of it? I believe that the most direct way would be to hold lessons outside. That would maximise both the exposure to full-spectrum light as well as a healthy amount of UV radiation. It might also be the most practical: it may be impossible to bring natural sunlight into all classrooms of pre-existing schools without major demolition.

There is precedent for this sort of activity. Argyle High School in Winnipeg has an extensive outdoor classroom that incorporates a pathway, benches, trees, and lots of open space. The classroom is mostly used for hands-on science. Indeed, a quick review of literature on outdoor classrooms shows that they are primarily for outdoor education classes. However, I think that any class could benefit from going outdoors. Simple natural settings provide few visual distractions and decrease noise distractions by eliminating the echoes caused by walls. Classes could be organised in a circular fashion, each student with a small bench or lawn chair. When it is time for students to focus on their work, tables could be brought out. A circular arrangement would ensure that the Teacher sees each student. Large open spaces might make outdoor classrooms difficult to control, but this could be solved with the planting of shrubs to create more intimate environments. Weather, of course, would pose problems. Students might be resistant to staying outside in below-zero temperatures. Still, it should become common practice – weather permitting.


Although the research about the effects of light on student performance and well-being is recent and inconclusive, it suggests that sunlight is beneficial because it provides ultraviolet and full-spectrum visible light. Teaching outdoors is relatively inexpensive, risk-free, and gives students ample sunlight. The academic performance of students in outdoor classrooms would be an excellent area for further study.


1 Sunlight has an equal amount of all visible colours. Full-spectrum lights attempt to copy the colour of sunlight.

2 These lights are rarely used in schools and are most common in street lamps.

3 Researchers tested the students at the beginning of the trial period (when they entered Grade 4) and at the end (when they left Grade 5)

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