Bright lighting is generally believed to make people more alert, and well-daylit spaces are generally perceived by occupants to be “better” than dim gloomy ones (Mardaljevic et al., 2012). Day- lighting has been associated with improved mood, enhanced morale, less fatigue, and reduced eyestrain (Robbins, 1986). Many studies show that the performance and productivity of workers in office, industrial, and retail environments can increase with the quality of light. Generally, employees prefer to be working as close as possible to daylight and can perform better as a result. This can also contribute to effective staff retention.  

There is a mounting body of evidence for lighting’s influence on “nearly every physiological, metabolic and behavioural system” (Lucas et al. 2014).

Companies have recorded an increase in productivity of their employees of about 15% after moving to a new building with better daylight conditions. which resulted in considerable financial gains (Edwards and Torcellini, 2002). Another study demonstrated that greater satisfaction with lighting conditions (both daylight and electric lighting) contributed to environmental satisfaction, which, in turn, led to greater job satisfaction (Veitch et al., 2008). 

Studies also show that  daylit  environments lead to more effective learning. It was found that students in classrooms with the most window area or daylighting produced 7% to 18% higher scores on the standardised tests than those with the least window area or daylight (Heschong, 2002). 

Research has demonstrated statistically-significant changes in heart rate variability (HRV), a reliable indicator of health risk as well as cognitive engagement, even in the presence of short-term exposure to electrical light (Edelstein et al. 2008). Light therapy has been applied to ameliorate conditions such as seasonal affective disorder (SAD), dementia, the effects of traumatic brain injury, and various sleep disorders; further, it has been used to counteract fatigue from jetlag, night shift work, and even space flight (Zatz [ed.] 2005).