Cool Roofs

Cool roofs is a term used to describe roofs that have high solar reflectance and high infrared emittance values that significantly lower the cooling load of the building, thus help reduce the building energy consumption. As reported by Oak Ridge National laboratory, cool can roofs save up to 40% in cooling costs.

Solar reflectance is the amount of solar radiation that a roof reflects. Cool roofs can achieve solar reflectance of over 70%. Reflected solar energy allows the roof to remain cooler, which means less heat is transferred into the building. For cool roofs the higher the value the better.

The infrared emittance of a roof is a measure of absorbed solar radiation that is emitted, or given off from the roof surface back into the sky. Emittance of metal roof can be as high as 90%. For cool roofs the higher the value the better.

Cool Roof Product Certification Programs:

Energy Star

In 1992 the US Environmental Protection Agency (EPA) introduced ENERGY STAR as a voluntary labeling program designed to identify and promote energy-efficient products to reduce greenhouse gas emissions.

Products that comply with the Energy Star criteria are eligible to carry the Energy Star label and are listed as an energy Star qualified product.

To meet the Energy Star requirements for low slope roofing (2:12 or less), the product must have an initial reflectivity of 0.65 and an aged reflectivity of 0.50 after three years of weathering. Reflectivity is not a function of product but of material.

To meet the Energy Star requirements for steep slope roofing (greater than 2:12), the product must have an initial reflectivity of 0.25 and an aged reflectivity of 0.15 after three years of weathering.

ButlerŽ Colors:

Color Reflectance Aged Reflectance Energy Star compliant

Low Slope Steep Slope

Galvalume 0.68 0.57 Yes Yes

Birch White 0.55 0.55 No Yes

Shell Gray 0.42 0.41 No Yes

Snow White 0.61 0.61 No Yes

Solar White* 0.70 pending* *Yes *Yes

Solar Green* 0.27 pending* *No *Yes

Warm White 0.55 0.54 No Yes

Marsh White 0.50 0.50 No Yes

Mesa Gray 0.25 0.25 No Yes

Country Wheat 0.51 0.50 No Yes

Inca Gold 0.46 0.45 No Yes

Sandalwood 0.34 0.34 No Yes

Santa Fe Red 0.22 0.21 No No

Burgundy 0.24 0.24 No No

Hunter Green 0.09 0.09 No No

Santa Anna Blue 0.16 0.16 No No

Evening Blue 0.18 0.18 No No

Bay Blue 0.12 0.12 No No

Terra Brown 0.10 0.10 No No

*Solar White and Solar Green colors are expected to meet Energy Star Requirements when aged samples are available.

CRRC - Cool Roof Rating Council

The Cool Roof Rating Council was created in 1998 to develop accurate and credible methods for evaluating and labeling the solar reflectance and thermal emittance (radiative properties) of roofing products and to disseminate the information to all interested parties.

The CRRC is incorporated as a non-profit educational organization for the following purposes:

To implement and communicate fair, accurate, and credible radiative energy performance rating systems for roof surfaces.
To support research into energy related radiative properties of roofing surfaces, including durability of those properties.
To provide education and objective support to parties interested in understanding and comparing various roofing options.

At the core of the CRRC is its Product Rating Program, in which roofing manufacturers can label various roof surface products with radiative property values rated under a strict program administered by the CRRC.

Solar White MR-24Ž has been processed by the Cool Roof Rating Council (CRRC). The information shown below will appear on the CRRC web site after the next update. The California energy efficiency standards require a CRRC rated cool roof for low slope roofs on conditioned buildings. The standards become effective October 1st. Butler now has a roof panel that meets the California requirements.

Company Name and Contact Brand Model Type Initial Solar Reflect. 3-year Solar Reflect. Initial Therm. Emit. 3-year Therm. Emit. Low-slope Steep-Slope CRRC Prod. ID

Butler Manufacturing Company
Mark Henry
816-968-5706 MR-24 Solar White Metal 0.70 pending 0.85 pending X X 0756-0001

Helpful links:
http://www.epa.gov/heatisland/strategies/coolroofs.html
http://www.coolroofs.org/
http://www.coolmetalroofing.org/
http://www.energystar.gov/
http://www.coolmetalroofing.org

Color	Reflectance	Aged Reflectance	Energy Star compliant
Color	Reflectance	Aged Reflectance	Low Slope	Steep Slope
Galvalume	0.68	0.57	Yes	Yes
Birch White	0.55	0.55	No	Yes
Shell Gray	0.42	0.41	No	Yes
Snow White	0.61	0.61	No	Yes
Solar White*	0.70	pending*	*Yes	*Yes
Solar Green*	0.27	pending*	*No	*Yes
Warm White	0.55	0.54	No	Yes
Marsh White	0.50	0.50	No	Yes
Mesa Gray	0.25	0.25	No	Yes
Country Wheat	0.51	0.50	No	Yes
Inca Gold	0.46	0.45	No	Yes
Sandalwood	0.34	0.34	No	Yes
Santa Fe Red	0.22	0.21	No	No
Burgundy	0.24	0.24	No	No
Hunter Green	0.09	0.09	No	No
Santa Anna Blue	0.16	0.16	No	No
Evening Blue	0.18	0.18	No	No
Bay Blue	0.12	0.12	No	No
Terra Brown	0.10	0.10	No	No

Company Name and Contact	Brand	Model	Type	Initial Solar Reflect.	3-year Solar Reflect.	Initial Therm. Emit.	3-year Therm. Emit.	Low-slope	Steep-Slope	CRRC Prod. ID
Butler Manufacturing Company Mark Henry 816-968-5706	MR-24	Solar White	Metal	0.70	pending	0.85	pending	X	X	0756-0001