Washington residential energy code

Washington residential energy code (2021 Washington State Energy Code, Residential (WAC 51-11R))

As of 2026-10-22. DOE's Building Energy Codes Program (energycodes.gov) lags state adoption, so where a state's own rule was read it governs and DOE's differing figure is noted. Residential means one- and two-family dwellings and townhouses. Local amendments can apply; check the code body before relying on a section.

Key features

Code in force: 2021 Washington State Energy Code, Residential (WAC 51-11R)
In force since: 2024-03-15
Adoption: Statewide mandatory code
The 2024 WSEC-R is proposed to take effect 2027-05-03; adoption is targeted for 2026-09-25 (WSR) or 2026-11-20 (SBCC snippet).
Verified against the state's own adopted rule or code-body page.

Governing body

State of Washington

Region

Applies to

General contracting HVAC Insulation Electrical Windows & doors

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