Cooling Potential of Cool Roofs

Reflective roofs can lower temperatures, bringing a wide range of benefits. Yet a WRI analysis of 78 cities shows they make up just 1% of roof area. Image by Marco Brivio/iStock Cities and towns in the Mediterranean and the Middle East have long used white or light-colored roofs and walls to help keep people cool. Today, cities from Ahmedabad to Singapore are also turning to cool roofs to reduce urban heat and lower energy demand. By reflecting rather than absorbing the sun’s energy, cool roofs can lower temperatures inside buildings and, when deployed citywide, reduce heat across entire neighborhoods. It’s a relatively simple solution to extreme heat in cities, yet it can bring big benefits to public health and energy use. Lower temperatures can save lives: A 2024 study estimated that heat-related deaths in the record-breaking summer of 2018 could have been 32% lower if all London roofs had been cool roofs. By lowering indoor temperatures, cool roofs also reduce the need for air conditioning, which, in turn, lowers energy use and associated emissions and household cooling bills. Additionally, they can be relatively inexpensive to install when included as part of roof replacement or repairs, since the building owner is already paying for materials and labor and installing a cool roof on a new building is comparable to the cost of a non-reflective roof. The need is especially urgent in low-income and informal settlements, where homes can trap dangerous levels of heat and residents often have few options for mechanical cooling. In many parts of the Global South, homes are also workplaces, making extreme indoor heat a threat not only to health and sleep but also to people’s ability to earn a living. Women can face additional burdens because they are often responsible for caregiving and household work.