Daylighting metrics based on illuminance, distribution, glare and directivity

A method is presented for assessing daylighting quality based on metrics related to illuminance, distribution, glare and directivity. The calculations are done using the programs RADIANCE and DAYSIM for a south-west and a north-west oriented offices in the CDP building in Montreal (latitude 45° 30'N). The results indicate that the following set of metrics is the most useful for assessing the daylighting quality of architectural spaces: Useful Daylight Illuminance (UDI), Daylight Glare Probability and Vector/Scalar illuminance ratio. The results also suggest that the daylight factor should be replaced by the UDI and that more empirical research is needed to establish appropriate criteria for acceptable luminance ratios in the case of well daylit buildings.