What does the "y" axis indicate on the Solar Reflective Index?

The "y" axis on the Solar Reflective Index (SRI) graph represents the elevation of surface temperature above ambient air temperature. This index is important because it quantifies the effectiveness of various materials in reflecting solar radiation and contributes to energy efficiency in roofing systems. By illustrating the temperature rise, it helps in assessing how much heat is absorbed by roofing materials as opposed to being reflected, which is crucial for understanding their performance in reducing heat islands and improving energy usage in buildings.

In this context, the SRI provides valuable data for architects and builders when selecting roofing materials that can minimize heat gain, thereby aiding in energy conservation and enhancing indoor comfort.