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 Yes


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 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 Office was terminated on July 1, 1996, and its functions were assumed by other agencies.

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

    The deadline to submit code changes proposals for the 2009 Washington State Energy Code was March 1, 2009. This code is expected to exceed the energy efficiency of the 2009 IECC, with an anticipated effective date of July 1, 2010.

    Code adoption was delayed and the 2009 WA State Code became effective Jan. 1, 2011.

    At the October 15, 2010 Council meeting, the date for implementation of the 2009 Energy Code was set for January 1, 2011. The Council will consider additional amendments on residential duct testing for existing homes at their next meeting on November 19, 2010.

    The 2009 Editions of the International Building, Fire, Residential and Mechanical Codes, along with the 2009 Edition of the Uniform Plumbing Code, went into effect July 1, 2010 as planned. State Building Code Council.

    On May 6, Washington was announced as one of the states that will participate in BECP's Compliance Evaluation Pilot Study.

    Adoption Process

    Changes to the state energy code are submitted to the State Building Code Council (SBCC) on standardized forms. Within 60 days of receipt of a proposed change, the SBCC decides if the proposal warrants further consideration. If the SBCC accepts the change, rulemaking begins and the change is sent to a Technical Advisory Group (TAG) for review. The TAG members have varying expertise in the construction industry related to the proposed change. After completing the review, the TAG submits its recommendations back to the SBCC. The SBCC then makes the final determination on acceptance. Legislative oversight is provided because the SBCC has two senators and two representatives 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. 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 next 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 the Northwest Energy Efficiency Council (NEEC).

    For residential buildings, the city or county, or its designated enforcement agency, regulate enforcement. Technical assistance is offered through the Washington State University (WSU) Extension Energy Program. WSU is also a technical advisor to the SBCC for energy-related items and assists the TAG.

    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.