Targeting buildings for energy-saving cool-wall retrofits: a case study at the University of California, Davis

Cool paints on exterior walls will save energy in air-conditioned buildings at hot-climate universities, such as the University of California, Davis (UC Davis). Cool paints are more reflective, typically lighter-colored versions of conventional paints. They can reduce air-conditioning demand by reducing the wall’s solar heat gain and decreasing heat flow into the occupied space. We calculated potential energy savings from cool paint modifications for 49 UC Davis main campus buildings. We analyzed the baseline building stock, directly measured wall albedos (solar reflectances), and created a model that estimates albedo from wall color. We also developed a method to identify those buildings that could benefit most from cool paint. About 35% of UC Davis campus buildings could be modified with cool paint, which could save annually up to $45,000 of energy costs, 3.1 TJ of source energy, and 86 t of CO2 equivalent emissions. Since light-colored paints cost no more than dark paints, payback time would be zero if cool paints are chosen when buildings are routinely repainted.