Philadelphia gave 340 seniors white roofs; homes cooled by 5°F, saving 560 kWh

Philadelphia tested a simple way to protect older, low-income residents from summer heat by putting reflective white roof coatings on hundreds of homes between 2001 and 2003. The Cool Homes Programme targeted elderly households living in the city’s older housing stock, where dark roofs could absorb intense sunlight and transfer heat into upper-floor rooms. Around 340 low-income seniors’ homes are cited in later accounts of the project, while programme records describe a broader group of hundreds of treated households. Monitoring found that the intervention substantially reduced heat entering the homes, with maximum ceiling temperatures falling by roughly 4–5°F. A later account also reported annual air-conditioning electricity savings of about 560 kWh per home. The project combined reflective roofs with insulation and other measures to improve comfort and energy efficiency.Philadelphia’s white-roof project targeted 340 low-income seniors’ homesPhiladelphia’s older rowhouses were particularly vulnerable to summer heat because many had flat roofs covered with dark roofing materials that absorbed sunlight. Heat collected on these surfaces could pass through the roof and make upper-floo...