U.S. Department of Energy - Energy Efficiency and Renewable Energy

Federal Energy Management Program

New and Underutilized Technology: Cool Roofs

The following information outlines key deployment considerations for cool roofs within the Federal sector. This information spans:

• Benefits
• Application
• Climate and Regional Considerations
• Key Factors for Deployment
• Ranking Criteria
• Resources

Benefits

Cool roofs stay cool in the sun by minimizing solar absorption and maximizing thermal emission while lessening the flow of heat from the roof into the building and reducing the need for space cooling energy in conditioned buildings. Cool roofs may also increase the need for heating energy in cold climates. For a commercial building, the decrease in annual cooling load is typically much greater than the increase in annual heating load.

Application

Cool roofs are applicable in most building categories.

Climate and Regional Considerations

Climate issues can affect cool roof performance. Cool roofs are more beneficial in warmer climates and may cause energy consumption for heating applications to rise in colder climates.

Key Factors for Deployment

Cool roofs have a lower impact the more insulation is used.

The Secretary of Energy directed all U.S. Department of Energy (DOE) offices to install cool roofs, when life-cycle cost effectiveness is demonstrated, when constructing new roofs, or when replacing old roofs at DOE facilities. Other Federal agencies were also encouraged to do the same.

Ranking Criteria

Federal energy savings, cost-effectiveness, and probability of success are ranked 0-5 with 0 representing the lowest ranking and 5 representing the highest ranking. The weighted score is ranked 0-100 with 0 representing the lowest ranking and 100 representing the highest ranking.

Resources

The following resources are available:

• Cool Roof Resources for Federal Agencies: FEMP list of resources designed to help Federal agencies assess and deploy cool roofs on Federal buildings.

• Cool Roofs: FEMP designated product category purchasing requirements for cool roofs.

• Guidelines for Selecting Cool Roofs: DOE presentation outlining Federal guidelines for cool roof purchases.

• Potential Benefits of Cool Roofs on Commercial Buildings: Report detailing energy, cost, and greenhouse gas savings benefits of cool roofs.

• Roof Products: ENERGY STAR overview, specifications, and frequently asked questions covering cool roofs.

• Cool Colors Project: Lawrence Berkeley National Laboratory (LBNL) program on the benefits of cool colors at reducing energy loads.

• Roof Savings Calculator: Online resource developed by an interagency cooperative to help residential and commercial buildings optimize roof design.

• DOE Cool Roof Calculator: Tool developed to estimate cooling and heating savings for flat roofs with non-black surfaces.

• Cool Roof Rating Council: Independent, nonprofit organization that maintains a third-party rating system for roof surfacing material properties.