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

New and Underutilized Technology: Green Roofs

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

Benefits

Green roofs place vegetation on the rooftop to reduce heat load and add insulation. It also reduces storm runoff from the roof.

Application

Green roofs are appropriate for deployment within most building categories with higher roof to conditioned floor area ratios and should be considered in building design, renovation, or during roof replacement projects.

Climate and Regional Considerations

Climate issues can affect the performance of green roofs.

Key Factors for Deployment

Green roofs have weight loading issues, which need to be considered prior to deployment.

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.

Federal Energy Savings Cost Effectiveness Probability of Success Weighted Score
0.4 3.0 2.8 33

Resources

The following resources are available:

  • Green Roofs: Federal technology alert on how green roofs can Federal building improve energy performance, help manage storm water, reduce greenhouse gas emissions, and mitigate the effects of urban heat islands.

  • Green Roofs: U.S. Environmental Protection Agency (EPA) overview of green roofs and the heat island effect.

  • Residential Green Roof Systems: National Association of Home Builders summary of residential green roof systems, manufacturers, testimonials, resources, and more.

  • Cost-Effectiveness of Green Roofs: American Society of Civil Engineers (ASCE) article on green roof cost effectiveness.

  • Roof Options: Report prepared for the City of Minneapolis covering roof options for the Target Center.

  • Center for Green Roof Research: Pennsylvania State University program focused on green roof research and development.

  • Green Roofs: Resource portal for green roofs, news, projects, and the industry in general.

  • Roof-Envelope Ratio Impact on Green Roof Energy Performance: Paper addressing the impact of roof-to-envelope ratio on overall energy savings of a green roof design over conventional roof designs.