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 Solar-Reflective Wall?

Save Energy

Save Money

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Air Conditioning

Reduce Air Conditioner Use

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Temperature

Lower Indoor Air Temperature

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Power

Reduce Peak Energy and Improve Grid Stability

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Global Warming

Combat Climate Change

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Urban Heat Island

Mitigate the Urban Heat Island

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Smog

Reduce Smog

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Healthy Lungs

Improve Public Health

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CRRC Home and Building Owners, Architects, and Contractors Brochure

Provides general information on cool roofs and their benefits, as well as an overview of the CRRC Rated Products Directory and FAQ tailored toward end users.

Download Brochure [PDF]

CRRC Cool Roof Energy Savings Brochure

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

Download Brochure [PDF]

CRRC Wall Rating Program Brochure

Provides general information about solar-reflective walls and the new CRRC Wall Rating Program.

Download Brochure [PDF]

CRRC Urban Heat Island Mitigation Brochure

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

Download Brochure [PDF]

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:

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Low-slope

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.

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Steep-slope

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

Subcategories

Asphalt Shingle

Asphalt shingle

Asphaltic Membrane

Modified Bitumen, Built-Up Roof

Coating

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

Liquid-Applied Roof Covering

Silicone

Foam

Foam Core Tile

Metal

Standing seam; Shingle, Tile, or Slate Facsimile

Polymer/Composite

Shingle, Shake

Single-Ply Membrane

PVC, KEE, TPO, EDPM, Hypalon

Stone/Rock

Aggregate, Slate

Tile

Clay, Concrete

Wood

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

Determining the Energy Savings of a Cool Roof

Cool Surface Savings Explorer is a database tool that can report the solar-reflective 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.”