February 23, 2023

What You Need to Know for 2023 Code Changes in the Northwest


Energy codes continue to evolve in the Northwest, as each state in the region evaluates and updates their energy codes on a regular cycle (typically every three years). Some energy code advancements are set to go into effect in 2023 and 2024, while others face a potential overhaul. Read these summaries of crucial code updates in Idaho, Montana, Oregon, and Washington.


The Idaho Residential Energy Code, that aligns with 2018 International Energy Conservation Code (IECC)—with weakening amendments—remains in place.

In 2020, Idaho Gov. Brad Little signed Executive Order (EO) 2020-01, also known as Zero-Based Regulation, which directed state agencies to cut “costly, ineffective and outdated regulations.” In its 2022 response, the Idaho Division of Occupational and Professional Licenses (DOPL) proposed eliminating many provisions of the energy codes in residential buildings. However, the Idaho Building Code Board voted 6-2 to reject the proposed revision and deletion of much of the residential energy code. Later in the meeting, the board voted unanimously to maintain the Idaho Energy Efficiency Building Codes Administrative Rules in Temporary Rule status. Since no formal recommendation or Pending Rule was submitted to the legislature, these rules are not due for consideration in the 2023 session. Throughout 2023, the Northwest Energy Efficiency Alliance and other energy efficiency advocates will continue to participate in rulemaking meetings with DOPL to explore how to maintain the important provisions that conserve energy and protect consumers.

To learn more about the Idaho Residential Energy Code and for additional code support resources, visit Idaho’s official code site at: https://www.idahoenergycode.com/residential-code.


In June 2022, Montana adopted the International Code Council’s 2021 IECC residential provisions, which went into effect September 8, 2022. Montana’s residential code was adopted with amendments that reduce the stringency of certain energy-efficiency building requirements. A summary of additional significant changes between the previous energy code (2018 IECC) and the current code can be found on Montana Department of Environmental Quality’s website. It is notable that Montana adopted the 2021 IECC residential provisions less than a year and a half since they adopted the 2018 IECC residential provisions.

To learn more about the Montana Residential Energy Code and for additional code support resources, visit Montana’s official code site at: https://deq.mt.gov/energy/Programs/code.


In 2022, the Oregon Building Codes Division (BCD) kicked off their 2023 Oregon Residential Specialty Code (ORSC) development process by submitting a baseline proposal that addressed their obligations under EO 17-20. EO 17-20 requires that the 2023 ORSC be energy equivalent to the U.S. Department of Energy’s Zero Energy Ready Home standard by 2023.

BCD then initiated a public code amendment proposal solicitation, and the Residential Manufactured Structures Board (RMSB) formed a Code Review Committee tasked with reviewing those proposals and making recommendations on what to adopt. Through its five meetings, the committee recommended to not adopt any substantial additional energy-efficiency proposals. As of the end of 2022, the recommendations were scheduled to go to the RMSB for consideration. Pending RMSB adoption and/or modification, the 2023 ORSC is expected to go into effect Oct. 1, 2023, and be mandatory as of Jan. 1, 2024.

To stay updated on the release of the 2023 ORSC, visit Oregon’s official code site at: https://www.oregon.gov/bcd/codes-stand/Pages/orsc-adoption.aspx.


In 2022, the Washington State Building Code Council (SBCC) and its technical advisory groups kicked off the residential Washington State Energy Code (WSEC-R) update process, which concluded in November. The SBCC was tasked with updating the 2018 WSEC-R to a 2021 WSEC-R, which would be based on the 2021 IECC and local amendments. After an extensive process, the SBCC voted to adopt the 2021 WSEC-R. Notably, upon going into effect, this code would be among the first to require electric or gas heat pumps for space heating in nearly all cases and water heating in many cases, with several exceptions. Low-rise multifamily buildings are the subject of another notable code change: interior corridor type buildings will now be required to comply with Washington’s commercial energy code instead of WSEC-R, while other low-rise buildings will have the option. The 2021 WSEC-R is expected to go into effect July 1, 2023.

To learn more about the Washington State Energy Code, visit Washington’s official code site at: https://sbcc.wa.gov/state-codes-regulations-guidelines/state-building-code/energy-code.

For 2018 WSEC support resources, visit the Washington State University Energy Code Support website and stay tuned as 2021 WSEC support becomes available: https://www.energy.wsu.edu/BuildingEfficiency/energycode.aspx.

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