Cities are often significantly warmer than the surrounding landscapes due to the summer “urban heat island effect.” This heating effect has a negative impact on the energy use, health, quality of life and economy of urban areas. Addressing this effect will only become more important because the world is rapidly urbanizing—within 50 years an estimated 80 percent of the world’s population will live in an urban area.

Cities are often significantly warmer than the surrounding landscapes due to the summer “urban heat island effect.” This heating effect has a negative impact on the energy use, health, quality of life and economy of urban areas. Addressing this effect will only become more important because the world is rapidly urbanizing—within 50 years an estimated 80 percent of the world’s population will live in an urban area.

Cool roofs and pavements can help cool down buildings and cities. Replacing roofs and pavements with more reflective materials could reverse the urban heat island effect. Cool, reflective roofs and pavements are readily available, typically pay back within one year when the roof is ready to be replaced, and help cities both mitigate and adapt to climate change while making them more desirable and comfortable places to live.

Benefits of cool buildings

• Cooling energy savings of 10 to 20 percent on the top floor of the building by reducing air conditioning needs—a cost savings potential of $735 million per year in U.S. commercial buildings alone;
• More comfortable indoor air temperatures;
• More comfortable and functional for residents of regions where the roof is used as living space;
• Likelihood of improved roof and equipment life due to reduced thermal expansion; and,
• Cost-effective investment versus a traditional technology that often pays back immediately when a roof is going to be replaced anyway.

Benefits of cool cities

• Better air quality—an annual economic benefit of nearly $1 billion annually in the U.S.;
• More resistant to heat and pollution related illness and death;
• Reduced peak energy demand;
• Delayed or reduced adoption of air conditioning; and,
• Healthier, more comfortable and enjoyable urban spaces.

Benefits to the planet

• Avoids CO2 emissions by reducing cooling demands
• Offsets the warming effect of approximately 1 year’s worth of global CO2 emissions – turning 100 square meters of grey roof white offsets the warming effect 10 tons of CO2.