The energy and climate benefits of cool roofs have been well established: By reflecting rather than absorbing the sun’s energy, light-colored roofs keep buildings, cities, and even the entire planet cooler. Now a new study by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has found that cool roofs can also save water by reducing how much is needed for urban irrigation.
The energy and climate benefits of cool roofs have been well established: By reflecting rather than absorbing the sun’s energy, light-colored roofs keep buildings, cities, and even the entire planet cooler. Now a new study by the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has found that cool roofs can also save water by reducing how much is needed for urban irrigation.
Based on regional climate simulations of 18 California counties, Berkeley Lab researchers Pouya Vahmani and Andrew Jones found that widespread cool roof adoption could reduce outdoor water consumption by as much as 9 percent. In Los Angeles County, total water savings could reach 83 million gallons per day, assuming all buildings had reflective roofs installed. Their study, “Water conservation benefits of urban heat mitigation,” was published in the journal Nature Communications.
“This is the first study to look at the link between water and heat mitigation strategies in urban areas,” Vahmani said. “You might not do cool roofs just to save water, but it’s another previously unrecognized benefit of having cool roofs. And from a water management standpoint, it’s an entirely different way of thinking – to manipulate the local climate in order to manipulate water demand.”
Read more at DOE/Lawrence Berkeley National Laboratory
Image: Berkeley Lab researchers Pouya Vahmani and Andrew Jones found that implementing cool-roofs over NorCal (a) and SoCal (b) leads to average urban evaporative water demand reductions of 15% and 18%, respectively. (Credit: Berkeley Lab)
