2018 Resources
These links provide useful information for complying with the Washington State Energy Code, especially for those who are new to building science.
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 www.energyplus.net and http://openstudio.net/. Technical documentation and background is available at https://bigladdersoftware.com/projects/energyplus/ and https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=916076. 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 (https://energyplus.net/node/96, https://escholarship.org/uc/item/0z78090x). PNNL has developed a set of residential prototype models available at https://www.energycodes.gov/development/residential/iecc_models. We welcome feedback and information from others with experience using hourly energy simulation software tools. Please contact us at energycode@energy.wsu.edu.
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.
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.