Expansive windows that let in too much daylight, on the other hand, can create the potential for glare and shadowed task areas that lead to excessive visual contrast ( Hopkinson, 1971).
Daylight impacts visual comfort, with small, too few, or occluded windows leading to fatigued and strained eyes ( Simonson and Brozek, 1948 Cowling et al., 1990) and depriving occupants of a long-distance view, which can provide a point of relaxation for the eye's muscles ( Wilkins et al., 1989). Visually, daylight and views may shape perceptions of indoor environmental quality with outsized influence, given that the visual system dominates cognitive processes in both real-time and recall ( Stokes and Biggs, 2014). Previous research, largely conducted in controlled laboratory settings or among vulnerable populations such as the elderly, has shown that the qualities of daylight-the intensity, spectra and timing-provide circadian-effective lighting that ultimately drive various bodily functions such as sleep and metabolism through non-visual pathways ( Paul et al., 2009 Tähkämö et al., 2018). Providing access to daylight and views of the outside impacts physical health through non-visual and visual pathways. Windows both control the amount of daylight entering the building and serve as the main mechanism for staying connected to the outside world, factors that ultimately impact the physical and mental health of occupants. In an office setting, optimizing indoor environmental quality has been shown to benefit physical health by reducing sick building symptoms and improving sleep and circadian entrainment, mental health by improving mood and reducing feelings of depression, and performance by enhancing the productivity and cognitive function of employees ( Edwards and Torcellini, 2002 Singh et al., 2010 Allen et al., 2016). Decades of research have demonstrated that the physical indoor environment is critical to multiple dimensions of occupant health and wellness. With people spending approximately 90% of their time indoors ( Klepeis et al., 2001), buildings are the main mediator of people's exposures to environmental factors-their ventilation systems control the quality of the air indoors and their heating and cooling systems maintain indoor temperatures that keep us comfortable, irrespective of the conditions outside. Our physical environments are a key determinant of human health, on par with genetics and access to medical care ( Schroeder, 2007). This study adds to the growing body of research demonstrating the importance of daylighting strategies in designing spaces that support the physical and mental health of occupants. When working in the office with electrochromic glass, participants were 8-fold more likely of report satisfaction with daylight conditions and 6.5-fold more likely to report satisfaction with views of the outside, were 48% less likely to report eyestrain, perceived a significant benefit to positive affect and were 77% less likely to report feeling depressed. 30 office workers spent 5 days working in each of two West-facing offices that were identical with the exception of the window treatment: one with dynamic electrochromic windows and the other with functionally standard windows partially occluded by a fixed roller shade. We extend this research to quantify its impacts on the perceived physical and emotional wellbeing of occupants in an office environment. Electrochromic glass windows are a solution designed to maximize occupant access to daylight and views throughout the day, and previous research has demonstrated the benefits they can impart on sleep and cognition. While buildings are designed with expansive windows to allow for abundant daylight and views, in practice, they are frequently occluded to control for heat and glare. 4Psychiatry and Behavioral Sciences, SUNY Upstate Medical University, Syracuse, NY, United States.3School of Architecture, University of Illinois Urbana-Champaign, Champaign, IL, United States.
Chan School of Public Health, Boston, MA, United States