What does the Solar Reflectance Index (SRI) measure?

The Solar Reflectance Index (SRI) specifically measures the solar heat rejection ability of a material. It is a numerical value that indicates how well a surface reflects solar energy and dissipates heat, primarily in relation to its temperature when exposed to sunlight. A higher SRI indicates a surface that reflects more sunlight and remains cooler, which can lead to a reduction in the urban heat island effect and decrease energy consumption for cooling.

This metric is particularly important in urban planning and landscape architecture, as it helps inform the selection of materials that can mitigate heat accumulation in built environments. As cities and developed areas expand, understanding how surfaces interact thermally with solar radiation becomes crucial for sustainable design practices.