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2018 Washington State Energy Code

New to the energy code? Please read this.

Our energy code team provides support to those who use the residential sections of the Washington State Energy Code (WSEC-R).

For assistance and updates:

2018 WSEC-R Training Opportunities

Please review training opportunities on various energy code compliance topics and duct testing before working on your permit application documents.

Questions About Commercial Portions of the WSEC?

Contact Evergreen Technology Consulting at 360-539-5300 or email If your project is a mixed use building, please contact Evergreen prior to working on residential low-rise R2 units.

2018 WSEC-Commercial

Permit Application Documents

Right-click the form name and save it to your computer so you can use the form's automated functions.

Options for Code Compliance

Prescriptive Method

The prescriptive path is the typical compliance approach. To follow this approach, you will need to complete a prescriptive worksheet, glazing schedule, and heating system sizing calculator.


  1. Table R406.2 in 2018 WSEC-Residential references two tables that are provided in 2018 WSEC-Commercial: Table C403.3.2(1)C and C403.3.2(2). These tables are copied here for your convenience.
  2. Table 406.3, Option 2, in 2018 WSEC-Residential references section numbers in the 2018 IRC and IMC that are no longer accurate. We will update our prescriptive worksheets and the Code Compliance Calculator soon to reflect these changes. In the meantime, here are the updated section numbers:
    • IRC 2015 Section M1507.3 Whole-House Mechanical Ventilation System corresponds to IRC 2018 Section M1505.4 Whole-House Mechanical Ventilation System
    • IMC 2015 Section 403.8 Ventilation Systems for Group R Occupancies corresponds to IMC 2018 Section 403.4 Group R Whole-House Mechanical Ventilation System

Prescriptive Worksheets

This approach is the simplest method of WSEC code compliance. A project complies with building envelope requirements if it meets all minimum insulation levels required.

Single-Family Prescriptive Worksheet - All Climate Zones with Table 406

Multifamily Prescriptive Worksheet - All Climate Zones with Table 406

Instructions for printing or emailing prescriptive worksheets

Prescriptive Checklist : This is a guide for those working to comply with the 2018 WSEC-R. It lists items that apply to most residential new construction projects but should not be viewed as a comprehensive list of code requirements.

Code Compliance Calculator

The Code Compliance Calculator is useful for volume builders who submit multiple building permit applications. It replaces the UA Alternative Worksheet (formerly referred to as the Component Performance worksheet) and includes the glazing schedule and the heating system sizing worksheet. Please see the readme file and video below for detailed instructions for using this form.

Code Compliance Calculator and readme

Glazing Schedule

Using the Prescriptive Method, all glazing must have an “area weighted average” U-Factor of 0.30. This means that some windows can have a higher U-factor than 0.30 and some can have a lower U-factor than 0.30, as long as the area weighted average is U-0.30 or lower. You may need to complete this form to document glazing compliance when applying for your building permit. It is useful to have tested values when filling out this forms. NFRC AMMA provides custom U-values.

Glazing Schedule

Heating System Sizing & Duct Testing

We recommend you use the HVAC sizing tool based on Manual J from Better Built NW.

The previous Heating System Sizing Worksheet may be useful only if you do not have cooling. This calculator assumes that your glazing products have an area weighted average of U-0.30. Choose insulation levels and enter the areas of each building component. Hover your cursor over the red triangles to see the embedded help notes. An instruction sheet is also provided.

Heating System Sizing Worksheet

Heating System Sizing Instructions

Duct testing documentation:

Duct Testing Standard (RS-33)

Duct Testing Affidavit (New Construction)

Duct Testing Affidavit (Existing Construction)

Alterations (Remodel) Worksheet

Requirements for alterations or remodels of existing structures differ from the requirements for new construction. When doing a combined addition and remodel, use the Alteration (Remodel) Worksheet for the remodeling portion and the Prescriptive Worksheet for the new portion. No credits from Table 406.2 are required and existing buildings are not necessarily required to meet all of the energy code requirements.

Alterations (Remodel) Worksheet

Compliance Certificate 

The certificate should be completed by the builder or other approved party and posted in the space where the furnace is located, a utility room, or another approved location in the building.

2018 WSEC Compliance Certificate

2018 Compliance Certificate - Instructions

Insulation Certificate for Residential New Construction

Insulation Certificate

Technical Assistance and Testing Resources

Duct Testers

This list of duct testers includes individuals who attended the one-day duct testing training offered by the WSU Energy Program or completed the online training, and meet the minimum requirements to test ducts for the WSEC.

Technicians who can verify that they have successfully completed duct testing training provided by the Northwest ENERGY STAR Program or Performance Tested Comfort Systems (PTCS) may also be qualified to test ducts under the WSEC.

Database of PTCS Technicians

PTCS Training

Home Energy Raters (HERS)

For information about Home Energy Raters, please see the Building Efficiency webpage.

2018 WSEC-R Resources

Training Opportunities

Permit Application Documents

Tech Assistance & Testing Resources

Additional Resources 

SBCC Interpretations

Relationship with SBCC

The WSEC-R team is not an affiliate of, nor do we speak for, the Washington State Building Code Council (SBCC). Official opinions of WSEC intent are made only by the SBCC in response to official inquiries submitted to SBCC by authorities having jurisdiction (AHJ). While we try to stay aligned with SBCC, the technical support we provide is advisory only and non-binding on AHJ, builders, designers, and building trades personnel who build or remodel residential structures. Please contact the State Building Code Council to discuss concerns about the new code.