20 December, 2023

Oregon Energy Code Frequently Asked Questions


1. How is the energy code developed?

Oregon’s energy code is administered through the Oregon Department of Consumer and Business Services, Building Codes Division (BCD), and each iteration is developed through a multi-stage public and board review process. The Residential and Manufactured Structures Board advises BCD on and approves the Oregon Residential Specialty Code (ORSC), which includes the residential energy code (Ch. 11). The Construction Industry Energy Board likewise advises BCD on and approves the Oregon Energy Efficiency Specialty Code (OEESC), which is Chapter 13 of the Oregon Structural Specialty Code.

In general, the code development process starts with BCD and the relevant code board drafting or selecting the base code, followed by opportunity for public proposals and code board review. Code boards can also form code committees to assist with a detailed review of code proposals. Each of these stages offers opportunity for public input. After board review and approval, recommendations are forwarded to BCD for subsequent agency review and approval. The final step of code adoption is the public rulemaking process, typical of any state agency rulemaking, which offers another opportunity for public review and comment. The rules, when filed, will specify an effective date for the new code. This effective date typically includes a 3–6-month phase-in period for the new code, during which either the outgoing or incoming code may be used.

For more specific information on code adoption, please refer to the BCD code adoption website:



2. How often is the code updated?

The typical code cycle is approximately three years.

3. How does Oregon’s energy code compare to other states?

Oregon was the first state to establish a state-wide energy code in the 1970s, and it continues to be among the most efficient in the country. The US Department of Energy, through its Building Energy Codes Program, maintains maps based on quantitative code analysis that compare and illustrate relative state energy code levels:


1. What version of the code is Oregon currently on?

For residential buildings, which refers to one- and two-family dwellings and townhomes, Oregon adopted the 2023 ORSC, which became effective on October 1, 2023. There is a six-month phase-in period, so this code will become mandatory on April 1, 2024. The 2021 ORSC, which went into effect on April 1, 2021, will continue to be the minimum residential code until the 2023 ORSC becomes mandatory.

2. What are the minimum envelope (wall, roof, window, etc.) insulation/thermal requirements for residential buildings?

Table N1101.1(1) of the ORSC provides the prescriptive envelope requirements for the residential energy code. This table lists the required performance in the form of a thermal transmittance U-factor that defines the rate of heat transfer through an assembly. There are multiple assembly types that can meet each U-factor, and common assembly type equivalent insulation R-values are listed in the table. U-factors of other assembly types may be calculated to demonstrate code compliance, and approved default U-factors for many assemblies are listed in the code in Table N1104.1(2) for easy reference. Additionally, if certain assemblies do not meet the prescriptive requirements but others are more efficient than their corresponding minimum requirements, a “trade-off” whole building thermal performance analysis may be used to demonstrate code compliance using Table N1104.1(1).

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