IECC Commercial Proposals

2021 IECC: Flexibility for the Future | 2021 IECC: Ready and Resilient | 2021 IECC: Residential

The following proposals have been submitted to the commercial energy code by NBI and the Northwest Energy Codes Group. These proposals address a wide range of issues and improve the code by adding additional efficiency, clarifying requirements and creating greater flexibility for code users.


Above-Grade Wall Definition: This proposal clarifies the definition of above-grade wall to ensure that all building elements that serve as part of the wall – especially floor edges and between-floor spandrels – are specifically treated as part of the wall by code requirements that reference the definition.

Commercial 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.

Commercial 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.
Section C401

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.


Conditioned Greenhouse Envelope Requirements: This proposal modifies the low-power buildings requirements in the code to add requirements specific to conditioned greenhouses.

Slab Edges: This proposal addresses the thermal bridges created by concrete floor slabs that penetrate the building thermal envelope, including exposed slab edges and cantilevered balconies. It requires that these thermal bridges be provided with thermal breaks or continuous insulation.

Fenestration: The proposal modifies the fenestration table by separating requirements for “punched opening” type windows that go in a framed opening from other fenestration types such as curtain walls, storefront fenestration and site-build fenestration. Punched opening windows can achieve better U-factors more easily and cost-effectively than the other fenestration types, but U-factor code requirements for this window type have been held back by the technological and cost effectiveness limitations of curtain wall fenestration systems, storefronts and site-built products. The proposal retains existing requirements for these fenestration types and introduces the fenestration requirements from the residential section of the code for punched opening windows.

Mandatory Air Leakage Testing: This proposal makes air leakage testing mandatory for certain buildings depending on building type, building size and climate zone.

Air Barrier Verification: The proposal includes a sequence of requirements to ensure effective installation of air barrier systems that includes inspections remediation of defects and reporting to the owner and code official.


Automatic Stop: This proposal adds an automatic stop requirement for HVAC equipment to complement existing automatic start requirements.

Demand Control Ventilation on Single-Zone Systems: Demand Control Ventilation on Single-Zone Systems.

Low-Power Fans: This proposals creates efficiency requirements for low-capacity ventilation fans such as bathroom and exhaust fans. The requirements are modeled on requirements in the residential code for these fans with efficiency requirements that have been updated to reflect current market availability.

Service Hot Water

High Input Service Water-Heating Systems: This proposal raises the efficiency requirement for large service hot water systems to .92 Et.


Dwelling Unit Lighting Efficiency: This proposal revises the lighting efficiency requirements for dwelling and sleeping units in commercial buildings (including high-rise multifamily) to reflect the current state of the market for energy efficient lighting. It also reorganizes the code section for greater clarity and usability.

Lighting Power Density: This proposal updates the LPD tables in the IECC to reflect advancements in lighting technology and lighting design practices. A majority of these values are from ASHRAE 189.1-2018 but some values were modified based on discussions with lighting designers and other stakeholders as part of the New York Stretch Code development process.

Indoor Horticulture Lighting: As written, the 2018 IECC leaves lighting used for energy intensive and rapidly growing indoor horticulture lighting completely exempt from efficiency requirements. This proposal removes the loophole by requiring lighting used for plant growth or maintenance to meet an efficiency metric based on an ANSI standard developed specifically for this lighting application.

Section C406

C406 Points Option: The current additional efficiency package options (C406) are all considered equal in the 2018 IECC; however, there is a great deal of variation in the energy savings. This proposal modifies the options requirement to introduce a point system that reflects the different savings potential (based on an analysis of the options by PNNL) of the different options based on climate zone and building type. This modification makes C406 more flexible and effective and allows for the addition of more options.

C406 Dwelling/Sleeping Unit Lighting Efficiency: This proposal modifies the C406.3 advanced lighting option to specifically include requirements for lighting used in dwelling and sleeping units in addition to the existing LPD improvement, closing a loophole in the existing language.

C406 Controlled Receptacles: This proposal introduces a new C406 option for controlled receptacles in offices. The requirement is based on a requirement the Seattle Energy Code.

C406 Kitchen Equipment Additional Package: This proposal creates a new Efficiency Package for Section C406 aimed at full-service and fast food commercial kitchens such as those found in Assembly Group A-2 or establishments that engage primarily in commercial food preparation and/or dispensing.

New C408

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.

Appendix CA

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.

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

Additional 2021 IECC Proposals

Flexibility for the Future Ready & Resilient Residential

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