November 14, 2005 in Salem, Oregon. Koyaanisqatsi, owner of Solar Energy Solutions in Portland, works full time as a solar panel installer and represents a growing trend for home owners in Oregon seeking energy efficiency. To protect an entire city’s residents from heat during summer, simply painting every rooftop white or opting for a reflective coating could help reduce outdoor temperatures across a city by 1.
Lead author of the study, Oscar Brousse at the UCL Bartlett School Environment, Energy & Resources, said in a press release: “We comprehensively tested multiple methods that cities like London could use to adapt to and mitigate warming temperatures, and found that cool roofs were the best way to keep temperatures down during extremely hot summer days. Other methods had various important side benefits, but none were able to reduce outdoor urban heat to nearly the same level.
“Commonly proposed urban passive cooling strategies, which should be considered as measures that directly lower the temperatures, include increased urban vegetation, roofs incorporating vegetation , or the deployment of highly reflective roofs that can be composed of different roofing materials , known as cool roofs,” the authors wrote in the study. “Changes to roofs can reduce indoor temperatures 67 or cooling needs in a building.
“While rooftop solar photovoltaic panels are primarily considered as a source of electrical power, they can also be considered as a passive-active strategy for impacting outdoor and indoor air temperature by increasing the roofs’ albedo and by transforming incoming solar radiation into electrical power that can be used to run the AC system,” the authors explained. “City scale impacts of any intervention are reduced when applied to a smaller area or fewer buildings.