Implications of fa？ades’ visual reflectance for buildings’ thermal performance

The surface properties of building fa？ades have implications for thermal performance of buildings and might also influence outdoor thermal comfort conditions for pedestrians. A surface property, which is frequently used by building engineers and specially architects, is the visual reflectance. In this article, effects of fa？ades’ visual reflectance on thermal aspects of building performance have been investigated in two parts. In the first part, the result of a field study is presented. The study explores the relationship between the visual reflectance of actual building fa？ades and the corresponding surface temperatures. A number of buildings with diverse fa？ade colors were selected. Surface temperatures were measured via infrared thermography. Fa？ades’ visual reflectance was derived via simultaneous measurement of the illuminance on the fa？ades and their luminance. Furthermore, incident solar radiation, ambient air temperature, and relative humidity were measured. The results of the field study display a non-random relationship between the building fa？ades’ visual reflectance and their surface temperatures. The second part of the research involved the deployment of a calibrated simulation tool toward exploring the impact of fa？ades’ visual reflectance on thermal performance of buildings. The results suggest that the magnitude of visual reflectance has little impact on indoor temperature and heating demand in case of fa？ades with external insulation layer but may influence cooling loads in case of non-insulated buildings