Investigation of visual comfort metrics from subjective responses in China: A study in offices with daylight

Investigations have been conducted in two side-lit office spaces in the perimeter zone in a laboratory building in Canton, China under various sky conditions. High dynamic range photographs and sensor measured values with associated participants (Chinese, n = 19) evaluated visual comfort preference responses were collected to investigate against a set of visual comfort metrics. Tested against an evaluation dataset consisting of 476 measurements, correlations were analyzed of vertical eye illuminance (Ev), daylight glare index (DGI), daylight glare probability (DGP), luminance ratio and window/workplane luminance. Results showed that simple luminance metrics (e.g. workplane luminance) & vertical eye illuminance outperformed complex glare indices (DGP/DGI) & luminance ratio. Furthermore, metric thresholds were identified based on the results of this investigation.