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.
