Energy Code

2021 Washington State Energy Code

  • WAC 51-11C (Commercial)  2nd Edition (Jan 2024)
         Errata for 51-11C 2nd Edition (Feb 2024)
      
  • WAC 51-11R (Residential)  2nd Edition (Jan 2024)
    Copy of Appendix A from the Commercial Provisions (Default Heat Loss Coefficients)

Effective March 15, 2024

Based on the 2021 IECC. Please note that "Residential" includes One- and Two-family dwellings, Townhouses and  R-3 buildings three stories or less, and Group R-2 buildings three stories or less with dwelling units that are accessed directly from the exterior. "Commercial" includes all buildings not covered under "Residential." 

 

2018 Washington State Energy Code

Effective February 1, 2021.

Based on the 2018 IECC,  "Residential" includes One- and Two-family dwellings, Townhouses and Group R-2 and R-3 buildings three stories or less "Commercial" includes all buildings not covered under "Residential" 

2015 Washington State Energy Code

Based on the 2015 IECC; "Residential" includes One- and Two-family dwellings, Townhouses and Group R-2 and R-3 buildings three stories or less "Commercial" includes all buildings not covered under "Residential" (Effective July 1, 2016)

2012 Washington State Energy Code

Based on the 2012 IECC; "Residential" includes One- and Two-family dwellings, Townhouses and Group R-2 and R-3 buildings three stories or less "Commercial" includes all buildings not covered under "Residential"  (Effective July 1, 2013)

2009 Washington State Energy Code

  • Chapters 1 through 10 (Single-Family Residential)
  • Chapters 11 through 15 (Multi-Family and Non Res) Includes RS 29 - Nonresidential Building Design by Systems Analysis 
    • Note:  See Ch 1-10 for Table of Contents, Definitions, and Default Tables
    • (Effective January 1, 2011)

2006 and Older Washington State Energy Code