The Cool Roof Rating Council, Leadership in Energy and Environmental Design, and Energy Star are three programs that establish ratings for “cool roof” products and coatings, which are materials used to build solar reflective roof surfaces that deflect heat and reduce the need to cool the buildings they top. All three are considered green programs as their services are geared toward promoting energy-efficient roof coatings that are environmentally beneficial. Their ratings for cool-roof products are based on the material’s solar-light reflectance (SLR), also known as albedo, a decimal or percentage indicating a product’s reflectivity of sunlight; thermal emittance (TE), a ratio that compares a product’s emittance of absorbed heat to that of a standard black surface; and/or the solar reflectance index (SRI), which is derived by computing both a product’s solar-light reflectance and thermal emittance and thereby indicates its total ability to reflect solar heat.
Cool Roof Rating Council (CRRC)
Unlike Energy Star and LEED, the CRRC is an independent board that assigns ratings for over 2,000 roofing materials. These ratings are based on the solar reflectance and thermal emittance of products, although the CRRC does not set a minimum required value for either. Aside from the fact that these ratings are used on such a wide variety of products, some benefits of using Cool Roof Ratings are that they are very reliable – the CRRC stringently tests the products it rates every year to ensure rating accuracy – and are all unambiguously assigned in strict accordance with specific and easily verified CRRC measurement properties.
Leadership in Energy and Environmental Design (LEED)
LEED is the U.S. Green Building Council’s voluntary certification program for sustainable structures. While Cool Roof and Energy Star ratings are more focused on energy efficiency, LEED’s emphasis is broader and concerned more with the environmental friendliness of buildings, although typically, products that are environmentally friendly also happen to conserve energy. Rather than setting a minimum rating for the solar reflectance or thermal emittance of products specifically, LEED assigns a minimum SRI value of 78 for low-slope roofing products and 29 for steep-slope roofing products. Since an SRI value takes both the albedo and thermal emittance of products into account, it is considered by some managers to be a more comprehensive and reliable value in determining the heat-reflecting ability of products than either SLR or TE alone.
The Energy Star product ratings board is part of both the US Environmental Protection Agency and the US Department of Energy (DOE). It is the only one of the three ratings programs that has a minimum requirement for solar reflectance: 0.50 to 0.65 for low-roof products and 0.15 to 0.25 for steep-roof products. Cool-roof products carrying the Energy Star label and certification are easily identifiable and are estimated to use between 20 and 30% less energy than federally regulated products. Building owners interested in using roofing products rated by Energy Star can easily compute the energy savings of projects by using the Roof Savings Calculator, which is available on the DOE’s website, and plugging in the product ratings.
All three certifications can be of value to building managers when they’re choosing materials. Some select products based on two or even all three company ratings. So it’s not absolutely essential that only one rating be adhered to at the expense of the others, but for builders and homeowners who wish to save on energy costs while promoting a healthy global environment, they should consider at least one of the three ratings boards when sourcing roofing supplies.
At Applied Roofing Services, we believe Spray Polyurethane Foam Roofing offers the best value in durability, energy efficiency, and environmental sustainability. Call us today to find out more about our Green Roofing Solutions.