Browse By Topic

*NOTE: The 2018 Code Effective Date has been extended to February 1, 2021. For more information, please visit:

On February 1, 2021, the HVAC Total System Performance Ratio (TSPR) goes into effect in the 2018 Washington State Energy Code (WSEC). This code update will save energy by requiring building designers to use more efficient HVAC systems evaluated on whole-system performance.

By accounting for full-system HVAC efficiency, TSPR levels the playing field for efficient technologies and promotes more efficient design approaches in the process. This is an improvement on prior Washington code, which disincentivized energy-efficient HVAC system types and designs by treating high- and low-performing HVAC systems equally.

TSPR is a performance-based compliance path for HVAC systems. It is defined as the ratio of the sum of a building’s annual heating and cooling load compared to the sum of the annual carbon emissions from energy consumption of the building’s HVAC systems.

To comply with the WSEC, the proposed system’s TSPR must be greater than or equal to the baseline system TSPR, and meet all other prescriptive code requirements.

Calculating TSPR does not require complex energy modeling. Engineers will have the option to input the characteristics of the building and its mechanical systems into a software tool, developed by Pacific Northwest National Laboratory, as a module within the U.S. Department of Energy’s Asset Scoring Tool.

There will be a series of TSPR trainings offered prior to the February code changes. To learn more and sign up for these live webinar trainings, visit:

Download TSPR one-pager

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.