Is the design guidance of color and material for urban buildings a good choice in terms of thermal performance?

In the design of urban buildings, regionality is take into account to ensure that the colors and materials used are consistent with the surrounding environment and urban development. This helps maintain the urban characteristics and local cultural values. However, the effects on the thermal environment are typically not considered in this process. To explore the rationality of the current urban design guidance, a field study was conducted in Xi'an-iHarbour. The surface temperatures of buildings with different colors and materials were investigated, and the solar radiation received by these surfaces was measured. The results show that variations in surface colors can lead to considerable differences in surface temperature, which are strongly and positively correlated with the amount of solar radiation received. In addition, the thermal inertia of the material can significantly influence the daily variation in the surface temperature. The current guidelines for Xi'an urban design have been found to be inappropriate. Low-thermal-inertia materials and light colors have been suggested to improve the urban thermal environment of Xi'an. The findings of this research provide insights on the thermal performance of building surfaces and provide ideas for the architectural design of other cities that also have thermal environmental concerns.