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, 2nd Printing (Sept 2024)
  Copy of Appendix A from the Commercial Provisions (Default Heat Loss Coefficients)
  Errata for 51-11R 2nd Edition, 1st Printing

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

• WAC 51-11C (Commercial)  2nd Printing
       Errata for the 1st Printing
       Errata for the 2nd Printing
   
• WAC 51-11R (Residential)  2nd Printing

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

• WAC 51-11C (Commercial) 3rd Edition, effective July 1, 2019 Insert/Replacement pages only
• WAC 51-11C (Commercial) 2nd Edition, 2nd Printing (with updates Effective October 1, 2017) 
• WAC 51-11R (Residential) (4th Printing) (with updates Effective October 1, 2017) 
  •   Appendix Chapters (2nd printing)
• WAC 51-11C (Commercial)          
• WAC 51-11R (Residential)  (2nd printing)
  • Appendix Chapters 

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

• WAC 51-11C (Commercial)  2nd Printing
  • (Errata pages for first printing - before July 15)
• WAC 51-11R (Residential) 2nd Printing
  • (Errata pages for first printing- before July 15)
• Appendix Chapters  2nd Printing
  • Errata page for first printing-before Sept 9)

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 

• 2006 Washington State Energy Code
  • RS 29 - Nonresidential Building Design by Systems Analysis
  • (Effective July 1, 2007)  
• 2004 Washington State Energy Code  
  • (See 2003 WSEC for RS 29)
  • (Effective July 1, 2005)
• 2003 Washington State Energy Code
  • RS 29 - Nonresidential Building Design by Systems Analysis
  • (Effective July 1, 2004)