TSPR | Washington’s New HVAC Energy Efficiency Rules

On February 1, 2021, new rules that level the playing field for energy efficient HVAC systems will go into effect in the Washington State Energy Code (WSEC). In preparation for the new rules taking effect, the state is offering a series of webinars and virtual training opportunities on HVAC Total System Performance Ratio (TSPR).


TSPR evaluates HVAC systems on whole-system performance rather than individual equipment types. This code update improves on previous Washington codes which disincentivized energy-efficient HVAC system types and designs by treating high- and low-performing HVAC systems equally. By accounting for full-system HVAC efficiency, TSPR will:

  • Result in more efficient HVAC systems
  • Avoid complex energy modeling
  • Reduce operating costs once the building is finished and occupied
  • Promote more efficient design approaches

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. The tool will exist as a module within the U.S. Department of Energy’s Asset Scoring Tool.


There will be a series of TSPR training opportunities offered prior to the 2021 code changes. To learn more and sign up for these live webinars, visit: waenergycodes.com/compliance_training.php.

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