Investing in Better Outcomes: The Impact of Daylight in the Built Environment

Abstract

This paper focuses on the value of research and evidence in the design process with a focus on daylighting. Daylight is utilized as an example of an environmental attribute of built spaces that can be optimized, and backed up with evidence and research supporting its positive human impact potential. The paper explores and discusses the dynamic value of daylight in the built environment. Supporting this, daylight’s associated human outcome benefits are underlined. Additionally, the paper explores strategies that optimize daylight in the built environment (glazing and fenestration strategies). A comprehensive literature review with a focus on daylight in the built environment and its associated value was conducted to identify knowledge gaps. The literature review focuses on daylight and its application in both office and assisted living environments (the two environments where daylight studies were conducted in this paper). Additionally, a light was shed on the associated value, or return on investment (ROI) of investing in daylight in the built environment. Two studies were carried out looking to understand the impact of various daylight levels on human health and wellbeing outcomes. The first study took place in an office environment. Subjects moved from a space with very minimal daylight to a space with more optimal daylighting conditions. The metrics included activity, sleep, and light levels (via the Philips Actiwatch). Additionally, surveys capturing environmental satisfaction, subjective wellbeing, organizational engagement, and performance at work were distributed. It was found that subjects responded well to the more optimally day lit space. Sleep improved by 10 min on average per night. Also, environmental satisfaction and subjective wellbeing survey scores showed measurable improvements. The second study focused on the impact of daylight in an assisted living environment. A group of residents living in various room types (receiving various daylight levels) took part in a two-week study. The metrics included activity, sleep, and light levels (via the Philips Actiwatch). Additionally, general health and personal routine surveys were administered. Certain patterns of behavior related to design attributes of rooms were found. For example, individuals residing in the “French Door room” type recorded the lowest average sleep levels. Both studies revealed which health outcomes could be important to stakeholders in justifying investing increased resources into a more research-driven design process. The paper also identifies reasons for research and evidence based-design to be adopted more often, as well as its significance for stakeholders.