Daylight Autonomy

Daylight Autonomy (DA) was the first of a string of annual daylight metrics, now commonly referred to as ‘dynamic daylight metrics’. It is represented as a percentage of annual daytime hours that a given point in a space is above a specified illumination level. It was originally proposed by the Association Suisse des Electriciens in 1989 and was improved by Christoph Reinhart between 2001-2004. It is a major innovation since in considers geographic location specific weather information on an annual basis. It also has power to relate to electric lighting energy savings if the user defined threshold is set based upon electric lighting criteria. The user is free to set the threshold above which Daylight Autonomy is calculated. For the graphs above, we selected a Daylight Autonomy threshold of 300 lux (DA300). The graphical percent values represent the percentage of the floor area that exceeds 300 lux for at least 50% of the time.

• Reinhart, C. F., Mardaljevic, J., & Rogers, Z. (2006). Dynamic Daylight Performance Metrics for Sustainable Building Design. Leukos, 3(1), 7-31.
• Reinhart, C. F., & Walkenhorst, O. (2001). Validation of dynamic RADIANCE-based daylight simulations for a test office with external blinds. Energy and Buildings, 33(7), 683-697.