How to Use Code Equivalence

The Design Energy Code is an input in extended project data section. For whole building projects without energy modeling, the Design Energy Code selection determines the savings for the project.  The savings percentage is a code equivalent % savings of the selected code to the code basis for the 2030 Challenge, which is CBECS 2003.

Step-by-step guide

The Design Energy Code Equivalent Percentage Savings values are based on a collaboration with New Buildings Institute, which utilizes the code determination analysis by Pacific Northwest National Laboratory (PNNL) for each new version of ASHRAE Standard 90.1 to establish zEPI scores that ultimately become the code equivalent savings (100 - zEPI).    

The AIA 2030 DDx Design Energy Code Equivalent Percentage Savings can vary over time, due to one or multiple of the following:
- Significant new research has been made available: An example is when ASHRAE started using 90.1-2004 as the baseline for their calculations to assist making new versions and versions of other codes comparable to a single version.  Leading up to this shift, additional research and analysis was completed to assess what the percentage savings between 90.1-2004 and CBECS 2003 (baseline for 2030 Challenge) should be.  An adjustment was made, which had a ripple effect across a number of design energy codes.  That update has now been incorporated into the DDx. 

-  Difference between the Pre-Publication and Final determination of % savings:  The timing of the PNNL final determination can vary, but they tend to issue a pre-publication notice near the release of a new ASHRAE version.    The pre-publication value will be associated with the design energy code initially, and it will be updated (if required), after the final determination has been published.
- Additional research and analysis has been provided to AIA for regional and/or international codes that warrant the value to be updated. 

Changes to the code equivalencies will only be updated at the point of saving and will not get updated across your projects unless you re-save the projects.

Design Energy Code Percent Reduction vs. Modeled pEUI Percent Reduction

1. If the % savings pEUI reduction for modeled projects is less than the design code % saving equivalent, consider adjusting your baseline so that you are meeting the design code equivalent % savings.
2. If using code equivalent savings the selected design energy code will drive the % savings
3. If a project has an energy model or will have an energy model, the % savings is derived from the pEUI and the baseline EUI.
4. If a project has an energy model or will have an energy model, check to make sure the % savings is a reasonable number – comparing to the code equivalent % savings is a helpful benchmark.
5. If the % savings value is unexpected, reevaluate and consider adjusting the baseline EUI.

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