King County energy code

2021Washington State Energy Code

The 2021 Washington State Energy Code (WSEC) is effective for applications deemed complete on or after March 15, 2024. 

The full code text of the 2021 WSEC is available on the State Building Code Council website.

The WSEC is split into two sections, one for residential buildings and one for commercial buildings. Pay close attention to the definitions below to determine which provisions to use.

2021 Washington State Energy Code - Residential Provisions

Use Residential Provisions for the following:

1. Single family homes
2. Duplexes
3. Townhouses
4. Group R-3 occupancy areas in buildings three stories or less in height above grade plane whose dwelling units are accessed directly from the exterior
5. Group R-2 occupancy areas in buildings three stories or less in height above grade plane whose dwelling units are accessed directly from the exterior
6. Accessory structures to residential buildings

2021 Washington State Energy Code - Commercial Provisions

Use Commercial Provisions for the following:

1. Group R-2 buildings with dwelling units accessed from interior corridors or other interior spaces
2. All other buildings not defined as residential above

2018 Washington State Energy Code

The 2018 Washington State Energy Code (WSEC) is the applicable code for applications deemed complete on or after February 1, 2021, and before March 15, 2024*.
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*Applications for commercial buildings received on or after January 1, 2023, and before March 15, 2024 are also subject to King County amendments to the 2018 WSEC.

• The full code text of the 2018 WSEC is available on the State Building Code Council website.
• The text of the King County commercial energy code amendments can be found in King County Code (KCC) 16.07.

Compliance forms for commercial buildings subject to King County energy code amendments:

• Building Envelope Summary
• Lighting Budget Calculation Form