Ready & Resilient

2021 IECC: Flexibility for the Future | 2021 IECC: Commercial | 2021 IECC: Residential

Zero energy is assuming a larger and larger place in both the current building market and goals for the sustainability of buildings in the future. Likewise, resiliency is becoming an increasingly important consideration in how buildings are constructed. The IECC has an important role to play in these topics.

The following proposals augment the code to ensure that buildings are ready for a future of greater resiliency and zero energy performance. They update existing requirements and definitions to align them with current market and policy trends and introduce new requirements to ensure that buildings built today can adapt to resiliency and zero energy goals in the future.


Renewable Energy Definition (1): This proposal updates the definitions related to renewable energy and renewable energy systems to provide greater clarity and to align them with current understanding of the shape and character of renewable energy sources in the market.

Renewable Energy Definition (2): This proposal updates the definitions of biomass-related renewable energy for greater clarity and specificity in order to ensure that biomass-based sources of energy can reasonably be considered renewable energy.

Minimum Renewable Capacity: This proposal creates a mandatory minimum requirement for onsite renewable energy systems. It requires a system that is approximately one-half of the capacity that has been a compliance package selection in Section 406 since the 2012 IECC. This proposal will expand the implementation of renewable energy in the market and ensure that buildings are built with the infrastructure necessary to support onsite renewable energy systems.

Storage Ready: Appendix CA provides a mechanism for jurisdictions to require buildings to be built with the infrastructure required for on-site renewable energy systems and a future of zero net energy. This proposal modifies Appendix CA provisions to ensure that there is design and space consideration for a standard sized battery rack, and for the connections to the electrical panels.

zEPI Compliance Option: This proposal adds a new compliance options for projects or jurisdictions striving for near net-zero energy performance. It leverages the zero Energy Performance Index (zEPI) utilized in the IgCC and sets a target based on the typical performance of actual zero energy buildings in the market.


Residential Renewable Definition: The residential section references renewable energy but does not include a definition for renewable energy. This proposal introduces a definition for renewable energy that is consistent with the definition from the commercial section.

Residential Renewable Energy Credits: This proposal impacts who may claim the environmental attributes of an onsite-renewable energy system. The environmental attributes of solar power, or other renewable energy, have market value that is reflected and transacted in Renewable Energy Credits (REC). It adds a definition for RECs and a requirement that those environmental benefits remain with the building if the energy is to be considered “renewable” for the purposes of the code.

Appendix RB Zero Energy Residential Appendix: This proposal creates an appendix that would provide cities and states a standard to define a zero energy home using the ERI compliance approach.

Contact Amy Cortese, NBI director of programs, at [email protected], with any questions.

Additional 2021 IECC Proposals

Flexibility for the Future Commercial Residential

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