There are two primary model energy codes adopted by states in the Northeast and Mid-Atlantic: the International Energy Conservation Code (IECC) and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1 Standards. The IECC contains code provisions for both residential and commercial homes and buildings, while ASHRAE 90.1 covers commercial buildings four stories and higher. While states often adopt the IECC for both residential and commercial homes and buildings, some states adopt the IECC for residential buildings and the ASHRAE 90.1 for commercial buildings.
Both model codes are updated on three-year cycles; the latest versions are the 2024 IECC and ASHRAE 90.1-2022. Generally, each new version of the model code increases energy efficiency performance and provides guidance and compliance pathways to help builders meet the code.
States also adopt other codes, such as the International Green Conservation Code (IgCC), to further enhance energy savings and measures that result in better indoor environments, lower impact on natural resources, better neighborhood connections and improved walkability.
International Energy Conservation Codes (IECC)
The International Energy Conservation Code (IECC) is the predominant energy code adopted by states in the Northeast and Mid-Atlantic. Developed by the International Codes Council (ICC), the IECC has provisions for both residential and commercial homes and buildings. The 2024 IECC was published in August 2024. DOE technical analysis, performed by Pacific Northwest National Laboratory (PNNL), estimates that buildings meeting the residential 2024 IECC would result in approximately 7.8 percent savings in site energy, 6.8 percent savings in source energy, and 6.6 percent energy cost reductions (national averages).
Learn More About the 2024 IECC
Watch Video Explainers on the 2021 IECC
ASHRAE 90.1 Standards
States often adopt the ASHRAE 90.1 standard to improve the energy efficiency of their commercial building stock. ASHRAE was founded in 1894 to advance human well-being via the built environment. ASHRAE promulgates model standards based on research and building science to improve energy efficiency, indoor air quality, refrigeration, and sustainability of buildings. They publish several standards to help states and communities reach their energy efficiency goals in the building sector, including the 90.1 commercial energy efficiency standard, 90.2 residential energy efficiency standard, 62.1 and 62.2 mechanical standards, and 189.1 green building standard. ASHRAE 90.1-2022 was released in January 2023. DOE estimates that commercial buildings meeting ASHRAE 90.1-2022 would result in national savings of approximately 9.8 percent site energy, 9.4 percent source energy, and 8.9 percent energy cost.
