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Answers & Opinions

The Council's Policies and Procedures, in WAC 51-04-060, allows the Council to issue opinions (interpretations) relating to the codes at the request of a local or state official, or their designee, responsible for implementation and enforcement of the specific code provision on which the opinion (interpretation) is requested. For the Council to provide a formal opinion (interpretation), a letter requesting the opinion (interpretation) needs to be submitted by a code official. The final opinions (interpretations) of the Council are advisory only. Opinions (interpretations) that have been finalized are provided through the links to the left.

Some of the opinions (interpretations) refer to illustrations, diagrams, and attached documentation. These supporting documents are not posted on the Web. If you would like a copy of a supporting document please request it from Council Staff.

Answers and Code Interpretations

Year Interpretation Number Code Section Number Code Edition
2025 25-02 R403.6 WA State Energy Code-Residential 2018
2024 24-29 R303 WA State Energy Code-Residential 2021
2024 24-09 R403.5.6, Water heater insulation WA State Energy Code-Residential 2021
2024 24-06 R406 Supplemental heating WA State Energy Code-Residential 2021
2024 24-05 R406 Supplemental heating WA State Energy Code-Residential 2021
2024 24-04 Table R402.1.3 / R503.1.1 Wall insulation in existing structure WA State Energy Code-Residential 2021
2024 24-03 R402.2.1 Ceilings with attic spaces WA State Energy Code-Residential 2021
2024 24-02 R406 Typos and Clarifications WA State Energy Code-Residential 2021
2023 23-08 R405, R406, C406 - Cited efficiency values WA State Energy Code-Residential 2018, 2021
2023 23-07 Definition, Residential building WA State Energy Code-Residential 2021
2023 23-04 R405, R406, C406 - Cited efficiency values: Supersedes 22-02 WA State Energy Code-Residential 2018, 2021
2022 22-02 R405, R406, C406 - Cited efficiency values WA State Energy Code-Residential 2018, 2021
2022 22-01 R402.2.5 / Table R402.1.3 Mass Walls WA State Energy Code-Residential 2018
2021 21-10 R406, Additional Energy Efficiency Requirements WA State Energy Code-Residential 2018
2021 21-09 R402.4.2, Fireplaces (Air leakage) WA State Energy Code-Residential 2018
2021 21-03 C408.3 Unvented Crawl Space WA State Energy Code-Residential 2018
2021 21-01 R405 Simulated Performance Alternative WA State Energy Code-Residential 2018
2020 20-14 C406.2 / R406.3 H/ERV efficiency WA State Energy Code-Residential 2018
2020 20-13 R402.4.1.2, Table R406.3, air infiltration WA State Energy Code-Residential 2018
2020 20-12 Table R406.3, Appliance credit 7.1 WA State Energy Code-Residential 2018
2020 20-11 Table R406.2, Fuel normalization credits WA State Energy Code-Residential 2018
2020 20-02 WSEC C404.5 and R403.5.5 WA State Energy Code-Residential 2015
2019 19-04 Table R406.2, Additional efficiency credits WA State Energy Code-Residential 2015
2018 18-04 R403.7.1, Electric resistance heat WA State Energy Code-Residential 2015
2017 17-21 R202, Def. of Residential in relation to accessory bldgs. WA State Energy Code-Residential 2015
2016 16-14 Table R406.2 WA State Energy Code-Residential
2016 16-13 Table R406.2 WA State Energy Code-Residential
2016 16-08 R402.2.7, Floor insulation WA State Energy Code-Residential
2013 13-15 R403.4.2 Pipe insulation WA State Energy Code-Residential
2011 11-19 503.8.1, Ductless Heat Pump Thermostatic Controls WA State Energy Code-Residential