Effect of exterior surface colour on the thermal performance of buildings

Abstract The effect of external surface colour on the thermal behaviour of a building has been studied experimentally as well as theoretically. Experiments were performed on scaled down units of 1 m3 volume, under different conditions; namely (i) completely tight building, (ii) effect of opening the door and (iii) of an overhang on the window for complete shading throughout the day. A computer simulation programme, based on periodic solution of the heat conduction equation, was developed to yield the time variation of the room temperature corresponding to the given meteorological parameters. As expected, the black painted enclosure recorded a maximum of 7°C higher temperature than the corresponding white painted enclosure during hours of maximum solar radiation, while during the night the two enclosures showed nearly the same temperatures (being the light weight constructions). The experimentally observed temperature meaasurements were quite consistent with the theoretical calculations within experimental accuracies (±2°C). The same software when used to simulate the behaviour of a normal sized heavy structure, predicted 4°C to 8°C higher temperature throughout a period of 24 hours for a black coloured surface than the corresponding white one.