A “cool” roof or wall reflects and emits the sun’s heat back to the sky instead of transferring it to the building below. Generally, lighter colored products are more reflective than darker colors, but color is not the only indicator of solar reflectance performance. Learn more by visiting “What is a Cool Roof?” and “What is a Cool Exterior Wall?

Save Energy

Save Money

Read More
Air Conditioning

Reduce Air Conditioner Use

Read More

Lower Indoor Air Temperature

Read More

Reduce Peak Energy and Improve Grid Stability

Read More
Global Warming

Combat Climate Change

Read More
Urban Heat Island

Mitigate the Urban Heat Island

Read More

Reduce Smog

Read More
Healthy Lungs

Improve Public Health

Read More

Understanding the Solar Reflectance Index: A Calculated Value Brochure

Provides general information about how Solar Reflectance Index (SRI) is calculated and interpreted.

Download Brochure

What is a High-Performance Roof System? Nonresidential Buildings with Low-Sloped Roofs

Provides an overview of high-performance roof systems and their impacts.

Download Brochure

CRRC Cool Roof Energy Savings Brochure

Provides general information on the factors that influence the energy savings of a cool roof.

Download Brochure

CRRC Wall Rating Program Brochure

Provides general information about cool exterior walls and the new CRRC Wall Rating Program.

Download Brochure

CRRC Urban Heat Island Mitigation Brochure

Provides general information about how cool roofs and walls help mitigate the impacts of the urban heat island effect.

Download Brochure

Learn About Cool Roofs and Walls: Information for End Users

Provides an overview of the impacts of cool roofs and walls and how to use the CRRC Rated Products Directories.

Download Brochure

Radiative Property Metrics

CRRC product ratings are based on two radiative surface properties: solar reflectance and thermal emittance.

Solar Reflectance is the fraction of solar energy that is reflected by the roof or wall’s surface.
Thermal Emittance is a measurement of how well a material can shed the heat it absorbs. Materials with a low emissivity will tend to retain heat. Imagine a metal wrench left in the sun; it will be hot to the touch due to its low emissivity. Emissivity and color are not directly correlated.

These two properties can be used to calculate the Solar Reflectance Index (SRI) of roofing products in accordance with ASTM E1980.

  • The solar reflectance and thermal emittance values are used to calculate the steady-state temperature of the product in comparison to a reference black surface and reference white surface

  • The SRI values range from 0 to 100, though a black surface with very low reflectance and emittance could score in the negatives while a very reflective and emissive white might score over 100

  • It is important to note that SRI is a calculated value, not a measured value, and is a convenient way to combine solar reflectance and thermal emittance into one value

  • Lawrence Berkeley National Laboratory developed an Excel tool that calculates SRI

General Roofing Information

Roof Slopes

All roofs essentially fall into one of two general categories:

I Stock 1301364452


Low-slope (less than 2 inches of rise over 12 inches of run (2:12)). Low-sloped roofs are commonly found on commercial buildings, but also can be found on single family homes and low-rise multifamily buildings (e.g., apartment buildings that are three stories or less). These roofs are referred to as “flat” roofs. Visit Low-Slope Roofing Product Types for more information.

I Stock 1131070543


Steep-slope (greater than or equal to 2 inches of rise over 12 inches of run (2:12)). Steep-sloped roofs are commonly found on single family homes, but also include some multifamily and commercial buildings. These roofs are sometimes referred to as “pitched” roofs. Visit Steep-Slope Roofing Product Types for more information.

Roofing Product Types

Roofing products are generally categorized as shown below.

General Category


Asphalt Shingle

Asphalt shingle

Asphaltic Membrane

Modified Bitumen, Built-Up Roof


Silicone, Acrylic, Polyurethane, Aluminum, SEBS, Urethane, Latex

Liquid-Applied Roof Covering



Foam Core Tile


Standing seam; Shingle, Tile, or Slate Facsimile


Shingle, Shake

Single-Ply Membrane

PVC, KEE, TPO, EDPM, Hypalon


Aggregate, Slate


Clay, Concrete


Cedar shingle

Search for roofing products by type on the CRRC Rated Roof Products Directory.

Product Types Currently Not Included in the CRRC Rating Program:

Ballasted Roofs: Ballasted roofs are roofing systems that include a waterproof material (like a single-ply membrane) weighed down with heavy materials called a ballast. The ballast is typically some sort of stone or concrete paver.

Green Roofs: Green roofs (also known as garden roofs or vegetated roofs) use plants as a roof covering. Though typically not highly reflective, green roofs can stay cool by evaporating water. They can also reduce stormwater runoff. Green roofs are distinct from cool roofs and are not rated by the CRRC.

Cool Roof And Wall Energy Savings

A highly-reflective roof can significantly reduce a building's cooling load (energy use) in many climates. However, it may also increase the building’s heating demand in winter months. This increase is usually greatly outweighed by the cooling energy savings achieved during summer months for all but the most northern climate zones in the U.S. Visit End User FAQs for more information.

In selecting a roofing product, it is important to understand your climate zone and the actual energy your home or building will save. The U.S. Department of Energy provides a free online cool roof calculator that can give an estimate of how much energy you will save. Please note that this calculator is only for low-slope (flat) roofs: DOE Cool Roof Calculator.

To help determine the energy savings of a cool roof, the below documents provide an overview of some of the primary factors that influence cool-roof energy savings and identify resources available to learn more.

Cool Roof Energy Savings Brochure

Cool Surface Savings Explorer is a database tool that can report the cool exterior wall and cool roof energy, energy cost, peak power demand, and emission savings simulated for many building categories. Instructions on how to use the Explorer tool and a link to the downloadable tool can be found in the California Energy Commission report, “Solar-Reflective “Cool” Walls: Benefits, Technologies, and Implementation, Appendix P: Cool Wall Applications.”

How do I get a Cool Roof?

As an independent and unbiased organization, the CRRC doesn’t recommend specific products or manufacturers. The links below can help you find a roofing contractor in your area. Talk to your contractor about which “cool” products they offer, and look them up on the Rated Products Directory. If you have questions about navigating the Directory, please see the CRRC Rated Products Directory User Guide.