November 30, 2021

Residential Energy Storage Systems Under 2021 IRC

The 2021 International Residential Code introduced notable changes for battery energy storage product listing, marking, and allowable locations.

Some points of confusion affecting requirements for battery energy storage systems in the 2018 International Residential Code (IRC) have been addressed in the 2021 code revision. The informational bulletin you can download here addresses the 2021 changes.

Here is a concise overview.

  • The marking requirement for battery systems aligns with UL 9540, resolving an inconsistency that was present in the 2018 IRC.
  • The 2021 IRC also introduces an exception from all energy storage system requirements in Section R328 if a system is marked “for use in residential dwelling units” and installed per manufacturer’s instructions and the National Electrical Code, also known as NFPA 70.
  • The location requirement specifies four types of allowable locations for energy storage systems, providing more detail than the 2018 IRC.
  • The listing requirement refers to the product safety standard for energy storage systems, UL 9540. But once again, as in the 2018 IRC, the code does not define UL 9540.

SEAC’s informational bulletin on Residential Energy Storage Systems Under 2021 International Residential Code (IRC) seeks to provide clarity for system designers and installers. We published the document in November 2021.

SEAC makes this information publicly accessible to anyone who fills in the download form on this page. Your privacy is important to us. We do not sell or share your personal data.


This material is based upon work supported by the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) under the Solar Energy and Technologies Office Award Number DE-EE0009002.0001. The views expressed herein do not necessarily represent the views of the U.S. Department of Energy or the United States Government.