Energy Code

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)

2008 and Older Washington State Energy Code