It is almost universally agreed that natural daylight is good for building occupants: for wellbeing, productivity and health outcomes. HBN documentation emphatically encourages good provision of natural light, as does related technical guidance from CIBSE, but it is not always clear what this means for the procurement team, or the design team, when embarking on a new project.
This review considers a relatively recent tool for good daylight design:
Climate Based Daylight Modelling (CBDM). This tool is being used increasingly widely, including for BREEAM 2018, LEED V4, and in the education sector. Unlike other design tools such as the Daylight Factor, CBDM includes for sunlight, exposure to which is known to aid wellbeing during convalescence.
We suggest that CBDM is uniquely placed to improve daylight design for healthcare environments, and that its use should result in better buildings, with better health outcomes for patients.