LEED Heat Island Reduction Credit

LEED (Leadership in Energy and Environmental Design) is a green building rating system developed by the US Green Building Council (USGBC), founded in 1993. It has evolved since 1998 through several versions, including LEED v4 (2013), v4.1 (2019) and LEED v5 (released 2025). Projects earn points across categories, with certification levels of Certified, Silver, Gold and Platinum.

The Heat Island Reduction credit, in the Sustainable Sites category, is the LEED credit most directly tied to roofing. It aims to reduce the "heat island" effect, in which dark roofs and paving absorb sunlight and raise urban temperatures.

How roofs earn the credit

Projects can comply using:

• High-reflectance roofing – roof surfaces that meet a minimum Solar Reflectance Index (SRI).
• Vegetated roofs – green roofs, which cool by shading and evaporation.
• A combination, using a weighted area formula.

Under LEED 2009 (Sustainable Sites Credit 7.2), for example, at least 75% of the roof area had to have an SRI of 78 or higher for low-slope roofs (29 or higher for steep-slope roofs), or at least 50% had to be vegetated, or an equivalent combination. LEED v4 and v4.1 retained the approach but moved to thresholds based on both initial and three-year aged SRI, reflecting the fact that roofs lose reflectance as they weather. The US EPA cites the LEED v4.1 Heat Island Reduction credit as an example of a voluntary program requiring minimum roof reflectance.

Data sources

Projects normally use reflectance and emittance values from the Cool Roof Rating Council directory to calculate SRI or to document aged values.

Practical effects on roofing choices

The credit has encouraged white and light-coloured membranes (such as TPO and PVC), reflective coatings and green roofs on LEED projects. On steep-slope roofs, lower thresholds make some light-coloured shingles, tiles and coated metal eligible.

Related programs

Other rating systems have similar credits, such as Green Globes in North America and BREEAM in the UK and Europe, though their criteria and metrics differ.