Examples of Climate-Based Daylight Modelling

The daylight factor persists as the dominant evaluation metric because of its simplicity rather than its capacity to describe reality. The daylight factor is insensitive to both the prevailing local climate and building orientation. The drive towards sustainable, low-energy buildings places increasing emphasis on detailed performance evaluation at the early design stage. Recent advances in lighting simulation techniques have demonstrated that reliable predictions founded on hourly climatic data are attainable. The first part of this paper describes the application of climate-based daylight modelling to recent projects in New York and St. Petersburg. A climate-based daylighting metric to replace daylight factors is described. The second part of the paper is a discussion on the origins and practice of “traditional” daylight modelling.