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State Profile

Code Type: Commercial Residential
Current State Code State Specific State Specific
Effective Date
Adoption Date
State Amendments No No
State Code Analysis*
Enforcement Mandatory Statewide Mandatory Statewide
Can use COM/REScheck


Commercial Residential
Current Model Code ASHRAE Standard 90.1-2010 2012 IECC
Yes Yes
Previous Model Code
ASHRAE Standard 90.1-2007
Previous Model Code
2009 IECC

Model Code Savings Potential

Statewide Savings Potential (2010-2030)
Energy (primary)

Consumer Cost Savings

Consumer Cost Savings
Annual ($)
Annual (%)
Life-cycle (30 year)
Simple Payback
Positive Cash Flow


Code Type: Residential Commercial
Field Study No No
Training Program No No


Code Type
Code Cost-Effectiveness Analysis
Energy Code Impacts Energy Code Impacts
EIA State Energy Profile EIA State Energy Profile

Additional Information



    Washington's first energy code, adopted in 1977 by statute, was a voluntary requirement. The State Building Code Act and State Energy Code Act (SECA) were passed by the legislature in 1985. The State Building Code Act gave rulemaking authority to the State Building Code Council (SBCC), which oversees all building and energy codes within the state. 

    The first statewide energy code, adopted in 1986, was applicable to all new buildings, and was based on ANSI/ASHRAE/IES Standard 90A-1980. 

    In 1990, the Revised Code of Washington (RCW) was amended by HB 2198. HB 2198 amended RCW 19.27A (Energy-Related Building Standards) and increased the insulation requirements for residential buildings based on the energy source cost. Different insulation requirements were established based on climate zone and fuel type. The State Ventilation and Indoor Air Quality Code was also established at that time. 

    In 1991 another amendment to RCW 19.27A resulted in a modification to the commercial energy standards that were contained in the 1986 energy code. The modifications included more restrictive exterior envelope insulation requirements, increased equipment efficiencies, more restrictive controls on HVAC equipment, minimum motor efficiencies, and reduced allowable lighting power allowances. The updated code is based on the ASHRAE/IESNA 90.1-1989 and became effective April 1, 1994. 

    The entire energy code is contained in the state of Washington Administrative Code (WAC), (Chapter 51-11 Washington Administrative Code). Chapters 1-10 "Residential Energy Code," contain the requirements for R-occupancy buildings (1994 Uniform Building Code), which include single-family dwellings, apartments, and residential portions of hotels and motels. Chapters 11-20, "Nonresidential Energy Code," contain the requirements for all other building occupancies. 

    The Washington State Energy Code (WSEC) was amended in 2001. The amendments included prescriptive unlimited glazing path and increased envelope insulation requirements for residential buildings. Mechanical equipment efficiency requirements based on ASHRAE 90.1-1999 for non-residential buildings were also included in the amendments. 

    In 2004 amendments were adopted by the SBCC for non-residential occupancies. Non-residential envelope, equipment, and lighting requirements were increased and meet ASHRAE 90.1-2001 standards. 

    The 2006 WSEC was adopted in November of 2006 and made effective July 1, 2007. For low-rise residential construction, its energy efficiency exceeded the 2006 IECC standards. For high-rise residential construction (four stories or more), the 2006 WSEC was more energy efficient than ASHRAE 90.1-2007 in all respects. For commercial buildings, the 2006 WSEC was roughly equivalent to ASHRAE 90.1-2004, save for equipment and lighting standards, which are somewhat more energy efficient. 

    In 2009, the Washington State Legislature and the Governor signed Senate Bill 5854, which directed the SBCC to adopt state energy codes between 2013 through 2031 that incrementally move toward achieving the seventy percent reduction in annual net energy consumption and to regularly report on progress to the legislature (RCW 19.27A.160). Since this legislation, the SBCC has made regular updates to the energy code, basing both the commercial and the residential codes on the latest IECC model codes with Washington-specific amendments.  

    Adoption Process

    The State Building Code Council (SBCC) adopts the state’s building codes, including the energy code. The SBCC is made up of 15 members appointed by the Governor, with seats representing different aspects of the construction industry and local government. Legislative oversight is provided by two state senators and two state representatives who serve as ex-officio nonvoting council members. 

    Changes are instituted on a three-year cycle corresponding with the International Code Council (ICC) International Building Code cycle. Changes to the state energy code are submitted to the SBCC on standardized forms. A Technical Advisory Group (TAG) is tasked with reviewing all proposed code cha The TAG is made up of members with different expertise in the construction industry. After completing the review of all code changes, the TAG submits its recommendations back to the SBCC. The SBCC then makes the final determination on acceptance.  Once final approval is granted by the SBCC, the rule is filed with the Washington State Code Reviser and then published in the Washington State Register. The final rule becomes effective after the following legislative session. 

    Enforcement Process

    For commercial buildings, the city or county, or its designated enforcement agency, can enforce the code or require the building owner to hire a certified nonresidential energy special inspector to perform the plan review and/or field inspection. The energy plan reviewers and special inspectors are certified through a program regulated by the Washington Association of Building Officials (WABO). Certification requires that individuals complete a comprehensive testing program and have specific credentials. Re-certification is required when changes are made to the code. Technical assistance is offered through Evergreen Technologies. 

    For residential buildings, the city or county, or its designated enforcement agency, regulate enforcement. Technical assistance is offered through the Washington State University (WSU) Energy Program. 

    Compliance Process

    Compliance is determined by plan review and inspection by the local building official. Plans and specifications must be submitted unless otherwise required by the building official. The building official may also require that the plans be stamped by a registered design professional for more complicated designs. The energy code for residential buildings establishes minimum/maximum requirements for R-values and equipment efficiencies. Field inspections are required before a Certificate of Occupancy is issued. The energy code for commercial buildings sets minimum inspection requirements for the building envelope, mechanical systems, and lighting installations. The building official has the power to interpret both the residential and commercial energy codes. The building official may also request the SBCC to render written interpretations of both the residential and commercial energy codes.