Development of experimental methods for quantifying the human response to chromatic glazing

Thermochromic (TC) windows have the ability to regulate daylight and control the solar heat gains that shape a building's internal environment. They therefore offer the potential to improve indoor comfort and reduce building energy demand when used in place of traditional clear glazing systems. However, the quality of the luminous environment is affected due to their chromatic appearance (e.g. common TC coatings impart a bronze or blue hue), resulting in changes to correlated colour temperatures (CCT). Previous studies show that experiments performed under daylight conditions are difficult to be control, while those conducted under artificial lighting conditions cannot faithfully reproduce window properties. In order to investigate the influence of TC windows on visual performance and comfort of subjects in an efficient and economical way, an innovative test room cubicle was designed. It is a mock-up office lit by an artificial window, simulating luminous conditions filtered through two types of TC window (one blue tinted and one bronze tinted). Clear glazing was used as a reference. Objective visual tasks involving Landolt charts and subjective assessments made using questionnaires were used to determine subjects' response to the three different luminous conditions. Results show that the experimental method is effective at determining human response to chromatic glazing. Additionally, the method is flexible due to its small scale and its ability to artificially represent different window types.