SAN FRANCISCO, CALIFORNIA — In the first U.S. study to measure the real impact of building energy codes on total household energy consumption, Climate Policy Initiative (CPI) found that U.S. building energy codes have reduced household energy use and greenhouse gas emissions. The study also found that states adopting these codes, which encouraged the use of highly efficient natural gas heaters and electric heat pumps, shifted their energy use away from oil and wood fuels towards lower-emissions natural gas.

Residential buildings consume 22% of U.S. primary energy use and produce 21% of U.S. carbon dioxide emissions, so the ultimate potential impact of building energy codes is substantial. Most states have adopted Department of Energy (DOE)-recommended model codes, first set in 1992 and subsequently updated several times; others have written their own standards. Seven U.S. states – Alabama, Mississippi, Missouri, North Dakota, Oklahoma, South Dakota, and Wyoming – do not have mandatory building energy codes. Other states such as New Mexico and Maine are considering reverting to less stringent codes.

CPI’s analysis, which reviewed states’ energy use from 1986 to 2008, found that states adopting national model codes have achieved an approximately 10% reduction in household energy use, and a 16% reduction in household greenhouse gas emissions.

“Engineering models suggest that U.S. building codes should deliver energy savings; we now have solid evidence that they do,” said Kath Rowley, director of Climate Policy Initiative‘s San Francisco office. “States looking for ways to reduce energy use should take note.”

The analysis is part of a broader project by CPI to evaluate the impacts of building policy in key regions around the world. In addition to the U.S. study, a CPI Berlin project indicated that targeting policy at different stages of the retrofit decision process may help Germany meet its target of 80% reduction in primary energy consumption of buildings by 2050. CPI at Tsinghua is completing a study on the methods used to assess the impact of Chinese building codes.

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Climate Policy Initiative (CPI) is a global policy effectiveness analysis and advisory organization. Its mission is to assess, diagnose, and support nations’ efforts to achieve low-carbon growth. An independent, not-for-profit organization with long-term support from George Soros, CPI’s headquarters are in San Francisco and regional offices are in Berlin, Beijing, Rio de Janeiro, and Venice.