Code Equivalent Savings

The Design Energy Code is an input in General Inputs section 1. For whole building projects where the value of the "Energy Model Status" input field is "Will NOT be Modeled" or "Will be Modeled", but the "Has the project established an EUI yet?" is not checked, 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 (CBECS 2003).

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 DDx Design Energy Code Equivalent Percentage Savings can vary over time, due to one or more of the following reasons:

  • Significant new research has been made available; for example, 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 were 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.

  • There could be a 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 as needed after the final determination has been published.

  • Additional research and analysis has been provided to AIA for regional and/or international codes that warrant an update of the value. Changes to the code equivalencies will only be updated at the point of saving and will not get updated across projects unless the projects are re-saved.

Design Energy Code Percent Reduction vs. Modeled pEUI Percent Reduction

  • If the % savings pEUI reduction for modeled projects is less than the design code % saving equivalent, consider adjusting the baseline to meet the design code equivalent % savings.

  • If using code equivalent savings, the selected design energy code will drive the % savings.

  • If a project has an energy model or will have an energy model, the % savings is derived from the pEUI and the baseline EUI.

  • 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.

  • If the % savings value is unexpected, reevaluate and consider adjusting the baseline EUI.

Design Energy Code Equivalents


Design Energy Code

Approximate %        Reduction from Average

ASHRAE 90.1-1999


ASHRAE 90.1-2001


ASHRAE 90.1-2004


ASHRAE 90.1-2007


ASHRAE 90.1-2010


ASHRAE 90.1-2013


ASHRAE 90.1-2016


California Title 24 2005 for high rise residential


California Title 24 2005 for single family residential


California Title 24 2008


California Title 24 2010


California Title 24 2013


California Title 24 2016


California Title 24 Non-Residential 2008


California Title 24 Residential 2005


California Title 24 Residential 2008


IECC 2003


IECC 2006


IECC 2009


IECC 2012


IECC 2015


*NECB 2011


Older than 1999


Massachusetts Stretch Code


Oregon Energy Code


Oregon Energy Code 2010


Oregon Energy Code 2014


Oregon Energy Efficiency Specialty Code 2010


Oregon Energy Efficiency Specialty Code 2014


Washington Energy Code


Washington Energy Code 2012


Washington Energy Code 2015


Note: These are estimates of code comparison based on analyses by Pacific Northwest National Laboratory, New Buildings Institute, and Architecture 2030. These percentages are provided to enable the inclusion of non-modeled projects in analysis for the AIA 2030 Commitment.

*Source for this code is from the National Research Council Canada and New Buildings Institute.