As Philadelphia summers get hotter and electricity costs rise, it can be harder for residents to keep their homes cool, comfortable, and safe during extreme heat. What’s more, the impact of extreme heat does not affect all residents the same way. Certain neighborhoods can get up to 30°F degrees hotter than others because they have fewer trees and more pavement, roads, and dark roofs. This is also known as the urban heat island effect.
In fall 2025, the Office of Sustainability partnered with the Energy Coordinating Agency (ECA) to test if a simple roof coating – known as “cool roofs” – can help cool homes and neighborhoods during hot weather. The pilot took place in Strawberry Mansion, one of Philadelphia’s warmest neighborhoods during the summer. Funded through the U.S. Department of Energy’s Energy Efficiency and Conservation Block Grant (EECBG) program, the pilot gave a free cool roof coating to 62 Strawberry Mansion households, including renters and homeowners.
What is a “cool roof”?
A cool roof is a white or light-colored coating that reflects sunlight instead of absorbing heat. This can help keep a home cooler, which may lower the need for air conditioning and reduce energy costs. Cooler homes can also reduce health risks during extreme heat.
Cool roofs are no more expensive than traditional coatings. They may even help protect roofs from heat damage by extending their useful life and reducing maintenance costs.
What does the cool roof pilot test?
The City’s pilot is testing how well cool roofs work for cooling individual homes and a community. It tests whether cool roofs can be applied across a neighborhood to help reduce the urban heat island effect.
After summer 2026, the City will follow up with participating residents to learn how the cool roof coating affected:
- Indoor air temperature
- Energy use
- Residents’ experiences with extreme heat.
The results will help determine how the City can expand the cool roofs pilot to more Philadelphia neighborhoods in the future.
To stay updated on the Office of Sustainability’s projects, news, and updates, sign up for the newsletter.
