Abstract
The average daylight factor is one of the most widely used methods for predicting the internal illuminance due to daylight. It is a simple tool that can be used in the early stages of design and can give information about the luminous environment inside a room. This method is supposed to be used under overcast sky conditions. Expanding the use of the average daylight factor to other sky conditions will encourage the use of daylight in buildings. Several methods have been proposed for the prediction of daylight based on the CIE Standard General Sky. However, most of these methods aimed for a detailed estimation of the internal illuminance pattern. This paper aims to investigate the potential for using the average daylight factor method under the ISO/CIE Standard General Sky.