The practical implications of the EN 17037 minimum target daylight factor for building design and urban daylight in several European countries.

Sufficient daylight in the indoor environment of buildings is important not only for vision and well-being as daylight also has significant non-visual effects on the human organism. The provision of daylight in the interiors of buildings significantly affects the architectural and urban parameters of the building environment. Harmonized EN 17037 introduced a number of changes and ambiguities to the relatively established principles of incorporating daylight in buildings in several European countries; these were significant for both architects and other stakeholders. This paper compares the long-standing practice and historical context of daylight provision according to the criteria of national standards in selected European countries (Germany, Czech Republic, Slovak republic, Sweden) with the minimum target daylight factor according to the harmonized EN 17037. The consequences of the methodological differences and design criteria of daylight provision are presented in case studies of the assessment of the daylight in residential rooms and typical school classrooms. Daylight factor and lighting distribution are analyzed for different room scenarios, different window configurations and obstruction angles according to local standards in the mentioned European countries versus EN 17037. The paper also highlights the practical impact of the EN 17037 criteria on building design and the extent of façade obstruction.