Global Cool Cities Alliance
The simple act of switching from a dark to a light-colored roof surface has a number of benefits.
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More and more people are choosing to replace dark-colored surfaces with reflective ones to help keep their buildings cooler and their energy bills lower. The simple act of switching from a dark to a light-colored roof surface has a number of benefits.
- The concept is simple. When sunlight shines on a surface, some of that solar energy is reflected back into space as light and some is absorbed on the surface as heat. A lighter colored surface (such as a roof or wall) will reflect more light and keep that surface and the areas around it cooler than a dark colored one.
- Buildings with a reflective roofs require less energy to cool and save building owners and residents money on their electricity bills.
- Cool roofs on buildings without air conditioning save lives during heat waves by lowering indoor temperatures by several degrees.
- It is not just the surfaces themselves that are cooler. By absorbing less heat, light colored surfaces also lower air temperatures.
- Cooler city air means fewer dangerous heat days and less smog — all of which makes cities healthier, more livable, and less vulnerable during heat waves.
- Cooler roofs can make an even bigger difference in urban communities of color, where dangerous heat conditions have an outsized negative impact on health and household finances.
- In addition to reducing greenhouse gas emissions through improved efficiency, increasing the reflectivity of surfaces cancels the warming effect of greenhouse gases already in the atmosphere and help us immediately address the challenges of climate change.
- Taken together, these benefits are worth billions of dollars to the growing number of people that live and work in urban areas.