Solar Reflectivity (SR) &
Solar Reflectance Index (SRI) by Color
Solar reflectivity or reflectance is the ability of a material to reflect solar energy from its surface back into the atmosphere. The SR value is a number from 0 to 1.0. A value of 0 indicates that the material absorbs all solar energy and a value of 1.0 indicates total reflectance. Energy Star requires an initial SR value of 0.25 or higher for steep slope (>2:12) roofs and 0.15 or greater after three years. Low slope roofs require an initial SR value of 0.65 or higher and 0.50 or greater after three year.
The Solar Reflectance Index is used for compliance with LEED requirements and is calculated according to ASTM E 1980 using values for reflectance and emissivity. Emissivity is a material’s ability to release absorbed energy. To meet LEED requirements a roofing material must have a SRI of 29 or higher for steep slope (>2:12) roofing and a SRI value of 78 or higher for low slope roofing.
Color |
SR |
SRI |
|
| Oyster White (WH) |
0.52 |
59 |
|
| Polar White (PW) |
0.58 |
69 |
|
| Light Stone (LS) | 0.50 | 58 | |
| Hawaiian Blue (BL) | 0.32 | 42 | |
| Sahara Tan (ST) | 0.36 | 38 | |
| Ash Grey (AS) | 0.48 | 56 | |
| Burnished Bronze (BR) | 0.28 | 29 | |
| Colony Green (GR) | 0.34 | 36 | |
| Fern Green (FG) | 0.28 | 29 | |
| Almond (AL) | 0.63 | 76 | |
| Snow White (SW) | 0.65 | 79 | |
| Scarlet Red (SR) | 0.42 | 47 | |
| Harbor Blue (HB) | 0.28 | 29 | |
| Hunter Green (HG) | 0.28 | 29 | |