Additional Resources

These links provide useful information for complying with the Washington State Energy Code, especially for those who are new to building science.

Building Components

Hot Water

Northwest Energy Efficiency Alliance (NEEA):

BetterBuiltNW: Heat Pump Water Heater Technical Guide for detached single-family new construction and additions greater than 500 sf.

Energy Star version 3.2 for Washington and Oregon


Tip Sheet 25: Converting a Garage to Living Space (includes floor insulating guidance)

Spray-Applied Foam Insulation tip sheet from the Seattle Department of Construction and Inspections.

North American Insulation Manufacturers Association
Empowers homeowners and professionals to make informed insulation choices.

Spray Polyurethane Foam Alliance
Develops tools designed to educate and influence the construction industry with the benefits of spray polyurethane foam roofing, insulation, coatings, and specialty installations.

Foam Sheathing Coalition
Educates building code officials, design professionals and residential builders about the benefits of using insulating foam sheathing products.

Structural Insulated Panel Association

Fenestration - Windows & Doors

National Fenestration Rating Council - Certified Products Directory
Search for NFRC-certified windows, doors, or skylights that match your criteria.

Thermal Envelope, Air Leakage & Ventilation

Air Barrier Association of America
Creates resources to help quantify energy savings based on using air barriers and increasing the airtightness of buildings.

Equipment & Appliance Efficiency

AHRI Directory of Certified Product Performance - HVAC & DHW

Energy Star - Appliances

Building Codes & Best Practices

Accelerating the adoption of energy-efficient building practices in residential new construction.

Energy Trust of Oregon

EPS Field Guide - Advanced Efficient Homebuilding: 2020 Edition

NEEA Codes and Standards Program
Supports stakeholders to develop, adopt, and implement energy codes.

2019-2020 Washington Residential New Construction Code Study, June 2020
2018 Washington State Energy Code Progress Toward 2030: Report to Legislature, Nov 2020

Washington Association of Building Officials (WABO)
WABO activities include promoting building codes and standards that safeguard public health and safety, assisting in development of national and state codes, and preserving local government control of code administration.

Washington State Building Code Council
Provides independent analysis and advice to the legislature and the Governor's Office on state building code issues.

Washington State Department of Commerce - Building Strategy Update

Washington State Department of Labor and Industries
   Manufactured Home Permits and Inspections, Tiny Houses

Building Science Consultants & Resources

BetterBuiltNW and Earth Advantage
Our training partners provide on-demand and live trainings that address best practices to meet and exceed code requirements.

HVAC Sizing Tool
This free, cloud-based tool for HVAC technicians, designers and home builders provides a quick room-by-room heating and cooling design load calculator for accurate HVAC system sizing. Find additional technical resources, live and online trainings, and marketing resources to support and promote energy-efficient home building at BetterBuiltNW.

Building America Solution Center
Provides residential building professionals with access to expert information on high-performance design and construction topics, including air sealing and insulation, HVAC components, windows, indoor air quality, and much more.

Building Science Advisor: Provides expert advice on building envelope system performance from industry’s best researchers and building scientists.

Residential Energy Services Network
Strives to make the energy use of all homes transparent, thereby driving residential sector energy use toward net zero.

Building Performance Association
   Back to Work: COVID-19 Resource Guide

Air Conditioning Contractors of America
National trade association furthering the interests of HVAC residential contracting businesses.

Energy & Environmental Building Alliance
A building science leader that offers training and technical assistance for it members.

Home Ventilating Institute & HVI Certified Products Directory

Passive House Northwest
A group of Certified Passive House Consultants and other individuals and organizations who promote highly energy efficient construction through implementing the passive house concept.

Wufi Passive House: Provides a wide range of resources about Passive House design.

Northwest EcoBuilding Guild
Empowers people through education to transform the built environment for long-term sustainability.

Testing Tools (envelope, duct work & HVAC commissioning)

Offers blower door systems, duct testing equipment, digital manometers, and other building science resources.

The Energy Conservatory (TEC)
Leading manufacturer of performance testing tools for the building science industry.

Residential Energy Dynamics Tools used by home performance analysts; WAP energy auditors, inspectors, and monitors; HERS raters; design professionals; building inspectors; engineers; and building science researchers.

Building Energy Optimization Tool (BEopt)
Evaluate residential building designs and identify cost-optimal efficiency packages at various levels of whole-house energy savings along the path to zero net energy.

Rebates & Tax Credits

Washington State Department of Commerce - Low-Income Energy Assistance Program

Bonneville Power Administration - Programs and measures for residential end users

Avista - Rebates available for qualified installations of residential energy-efficient equipment.

Puget Sound Energy - Efficiency Boost rebates can help make home energy efficiency upgrades more affordable.

Energy Star Product Finder

Air Leakage & Duct Testing Resources

Air Leakage Testing

Benefits of Duct Sealing

Blower Door Test Results Form

Duct and Blower Door Test Hand Calculator

Duct and Blower Door Test Calculator (Excel)

Duct Testing Standard (RS-33)

Duct Testing Affidavit (New Construction)

Duct Testing Affidavit (Existing Construction)

Getting to Know Your Vent. System: Exhaust Type


These videos are old but still provide useful information.

"Duct Sealing for Comfort, Energy, and Indoor Air Quality" (16:45 min.)

Air Leakage in Homes: The Invisible Thief (39.11 min)

Introduction (2:19)

Why Air Seal? (3:21) 

Air Sealing For New Homes (20:41)

Measuring Building Tightness (4:28)

Air Sealing for Existing Homes (5:12)

Combustion Safety (2:50)

Final Thoughts (1:40)

Fresh Air for a Healthier Home (29 min)

Play All - recommended (29 min)

Why Ventilate? (4:53)

Exhaust-only Systems (5:28)

Integrated Systems (4:07)

HRV/ERV Systems (4:26)

Installation & Inspection (5:10)

Upgrading Existing Homes (5:35)

WSU Energy Code FAQs

Slabs and Below-Grade Walls: Prescriptive Path (December 2023)

U-Factors for Non-Prescriptive Constructions (October 2023)

Conditioned Crawlspaces (July 2023)

Fenestration: Windows, Doors and Skylights (Updated: October 4, 2023)

Buried Ducts (Updated: October, 2023)

Code Requirements for Heated Buildings that are Not Dwelling Units (November 2022)

Log Walls (Updated July 2023)

Two Heating Systems (October 2022)

Whole House Ventilation Systems (Updated: November 2022)

Hot Topics Archive

ACEEE Ducts Inside

Additions and Ducts

Comparing the Moisture Performance of Wood-Framed Wall Systems

Efficient Water Heating

Electric Heat Lock Out on Heat Pumps

Energy Efficient Home Cooling

Externally Applied Building Insulation

Indoor Air Quality - Keeping Homes Dry

Inspecting Attic Insulation

Principles of Heat Transfer

Unvented Attics

Insuladd - Ceramic-Based Paint Additive

UltraCBF rFOIL - Foil-Faced Bubble Wrap

Unvented Crawl Spaces

Ventilation and Indoor Air Quality Code

Options for Code Compliance

The 2018 WSEC-R provides the following compliance options:

R402.1.1 Prescriptive Path: The simplest approach that allows for unlimited glazing in most cases. Use the single family worksheet for single family, townhomes and additions. Use the multifamily R2 worksheet for low rise multi-family corridor or non-corridor buildings up to three stories. This path also requires compliance with R406 fuel and energy credits.

R402.1.4 Total UA Alternative Approach Component Path: This approach is rarely used, especially when the glazing to floor area exceeds 15%. This path also requires compliance with R406 fuel and energy credits.

R405 Simulated Performance Alternative Path:This path relies on energy simulation computer program modeling software. To be approved the software must be capable of modeling the standard reference design and proposed design as specified in Table R405.5.2(1), including the footnotes. Table R405.2 also requires R406 compliance. The requirement that eliminates most software tools from the simulation pathway is footnote "a" of Table R405.5.2(1), which says: “Hourly calculations as specified in the ASHRAE Fundamentals, or the equivalent, shall be used to determine the energy loads resulting from infiltration.” WSUEP has not performed the detailed reviews that would be required to identify software meeting these requirements. Your building official, who is the authority having jurisdiction, has authority to approve simulation software and your energy simulation results using the simulated performance path.

A preliminary review of background material indicates that EnergyPlus may meet the requirements. EnergyPlus and OpenStudio are free and open source, available for download at and Technical documentation and background is available at and The CEC funded development such that EnergyPlus can be used to model typical residential geometries, constructions, and HVAC systems, including ductwork in unconditioned spaces, which were previous concerns (, PNNL has developed a set of residential prototype models available at We welcome feedback and information from others with experience using hourly energy simulation software tools. Please contact us at

R406 Additional Energy Efficiency Requirement: These requirements are based on energy and fuel credits required in WSEC-R. Use the single family and multifamily prescriptive worksheets.

R407 Passive House Path: This new compliance path in the 2018 WSEC-R allows certified Passive House projects to achieve compliance with WSEC-R. There are requirements for documentation at plan review and final site inspection. See Passive House Northwest for more information.

Example of a PHIUS Final Project Certificate

New 2018 Code Compliance Calculator: This new compliance tool is designed for both R402.1.1 (prescriptive) and R4021.4 (UA Component) paths. It includes the glazing calculator and simple heating system sizing all in one worksheet. This tool can also calculate Efficient Building Envelope Options 1.3 – 1.6 using the % UA reduction in R402.1.1 path, in lieu of using the specific measure receipts highlighted below. This option in this new tool provides more flexibility to optimize energy credits, based on custom envelope measures.

State Building Code Council Resources

The Council establishes the minimum building, mechanical, fire, plumbing, and energy code requirements necessary to promote the health, safety, and welfare of the people of  Washington, by reviewing, developing and adopting the state building code. Pages of the Council website that may be of interest to energy code users include:

New to the Energy Code?

If you are not familiar with the Washington State Energy Code, we provide myriad resources to help you get up to speed. Please review the materials below and throughout the website before contacting us for assistance.

  • Familiarize yourself with the resources provided on the Energy Code website.

The worksheets and forms that a building official may require for a project vary from jurisdiction to jurisdiction and project to project. We recommend you contact your building official to discuss your project and what forms will be required.

The three worksheets that are most often required by building officials for new construction are: 

  • Prescriptive Worksheet – All Climate Zones: This worksheet is used to identify prescriptive requirements and the energy credits that you will need to achieve for new construction and additions.
  • Glazing Schedule: A building official may require you to fill out this schedule of the quantities, dimensions and U-values to obtain a weighted average U-value for your windows and skylights. The building official may not require this worksheet, especially if it is clear on your plans that your window and skylights meet code requirements.
  • Heating System Sizing Worksheet: A building official may require a heating system sizing worksheet to provide information on heating system required. Note this worksheet is limited in that it does not do cooling system sizing or handle multiple zones. It is preferable to submit a sizing calculation complying with the “Manual J” method from your heating contractor.  

Please see the Home Energy Raters webpage for a list of home energy raters under WSU Providership, which includes contact information for raters who have indicated that they are available to assist with related building science tasks, specifically with requirements of the energy code. You can also search for other qualified home energy raters by name in the RESNET raters registry or by state, area, company or name.

After you have reviewed these materials, you are invited to contact us with your specific questions.

Previous Energy Codes

Click here to see previous Energy Codes.