Lighting

Current research has demonstrated that natural light provides “an array of physical and mental health benefits” (Porras Álvarez, 2020, p. 4167). Positive effects of natural light also include an enhancement of visual, emotional, and psychological well-being (Gou et al., 2013). A case study from Porras Álvarez (2020) carried out with 278 university students over the course of six years aimed to determine how natural light could impact intellectual performance. The participants in the study took a course from March to June that consisted of three, one-hour lectures. The course was taught once per year for six consecutive years. The participants were all senior undergraduate students between 22 and 27 years of age. The classes were all carried out on the same campus at the same time of year so as to control any possible geographical or climatic variations. The classes always occurred at the between 9:00 am and 11:45 am so that there could be no variation based on alertness levels of the students. Of the six times the course was taught, three took place in an exclusively artificially lit basement classroom, while the other three took place in classrooms that had a mix of natural and artificial light. The classes were all lit by full spectrum fluorescent lamps (6500 K) to avoid any variance in results based on the colour temperature of the lighting. The basement and window classrooms were compared with data and attendance scores. The results showed strong evidence that deprivation of natural light had a negative impact on the intellectual ability of the participants. Comparing the entire population of window and basement classrooms, the students in the classrooms with windows showed exam scores that were 13.13% better than those of the students in the basement classrooms. Even when eliminating the two years with the most extreme data (best and worse exam scores), the mean exam score for windowed classrooms was still 7.73% better. The results of this study indicate that it is beneficial to students to have windows in their classrooms that will allow for natural lighting in combination with artificial lighting.

A study from Winterbottom and Wilkins (2009) aimed to assess the extent to which students in schools in the United Kingdom (UK) are exposed to aspects of classroom lighting that have been shown to cause discomfort and impair task performance. To gather data, lighting conditions were sampled in 90 classrooms across eleven secondary schools. Their results demonstrated that fluorescent lights cause headaches, impair visual performance, and lead to more repetitive behaviors in students with exceptionalities. Unfortunately, around 80% of classroom lighting comes from fluorescent bulbs.

Winterbottom and Wilkins (2009) recommend that new classrooms should have dimmable lights and blinds that are regularly maintained that can control levels of daylight in the classroom. This allows teachers to find levels of lighting in the room that are most helpful to students, as well as to reduce over lighting and glare.

According to Winterbottom and Wilkins (2009), whiteboards should be tilted away from the wall so that glare is directed towards the ceiling. Glare from whiteboards can distract students and impair their vision.

Keis et al. (2014) studied the impact that blue-enriched lighting could have on students’ cognitive performance. Their study involved 58 high school students who were recruited from two schools in Ulm. The students were all of similar age and had similar educational backgrounds and socio-economic status. The results of the study showed increased performance in the classrooms that used blue-enriched white lighting. Improved performance came in the form of increased cognitive processing speeds and concentration. The authors concluded that the blue-enriched lighting seemed to influence basic information processing, as there was no effect on short-term coding and retrieval of memories. They also stated that blue-enriched lighting “acts as a zeitgeber and entrains the human circadian clock. Correspondingly, missing short-wavelength light in the morning postpones entrainment and leads to a delay of circadian cycle of high school students” (Keis et al., 2014, p. 91).

Choi et al. (2019) conducted a study in which their goal was to investigate physiological and subjective responses of students to morning light exposure with different colour temperatures. The melatonin and cortisol levels of fifteen university students were measured and compared after an hour of morning light exposure to both warm (3,500 K) and blue-enriched (6,500 K) white lights at recommended levels for classrooms. Perceptions of sleepiness, mood, and visual comfort were also compared. The participants had an average age of 23.35 and included eight men and seven women. All the participants were exposed to both types of lighting, though the order in which they were exposed was randomized. Saliva samples were taken before and after the light exposures to measure melatonin and cortisol levels. The subjective measures of sleepiness (sleepiness, mood, and visual comfort) were rated using the Karolinska Sleepiness Scale (KSS). Results showed that the decline of melatonin levels associated with waking up was much greater after the exposure to blue-enriched (cooler) light than the warmer light. The blue-enriched light also such a significant improvement in subjective perception of alertness, mood, and visual comfort. There was no significant difference found in cortisol levels between the two lighting conditions. These results would suggest that using blue-enriched lighting may help students with early morning drowsiness and students with a tendency to doze off in morning classes.

Students who participated in the studies from Keis et al. (2014) and Winterbottom and Wilkins (2009) both preferred lower colour temperature lighting. This warmer lighting was preferred due to the brightness, light colour, and pleasantness. Many considered the blue-enriched lighting to be too bright.