The 2027 IECC Scope and Intent, including additional Code Council Board of Directors Commentary, has been finalized after careful consideration of public comments.  The following represents the final scope, intent, and associated commentary for both the commercial (CECDC) and residential (RECDC) committees.

Please refer to the IECC related committee page for more information on the committee activity: https://www.iccsafe.org/committees/energy-iecc/

Commercial | Scope & Intent

C101.2 Scope.

This code applies to the design and construction of new and existing buildings including additions, alterations, repairs and changes of occupancy and use, not covered by the IECC Residential.

C101.3 Intent.

The purpose of the International Energy Conservation Code-Commercial is to provide market-driven, enforceable requirements that achieve a reasonable level of energy efficiency that is safe, technologically feasible, and lifecycle cost effective, considering economic feasibility, including potential costs and savings for consumers and building owners, and return on investment. Additionally, the code includes ANSI/ASHRAE/IES 90.1 as a compliance method. Requirements contained in the code will include prescriptive and performance-based compliance options. The code will provide for the safe and efficient use of energy sources and is not intended to eliminate any fuel type.

The code may include non-mandatory provisions incorporating additional energy efficiency and greenhouse gas reduction resources and provisions that lead to achievement of zero energy buildings. Such provisions shall either be (i) in optional appendices or (ii) in the base code provided as options where compliance with the code is still possible without complying with those provisions. This code’s intent statement does not require the exclusion of provisions contained in prior editions of this code.

Commercial | Commentary

The ICC Board of Directors provides the following additional commentary to be written in the IECC Commentary and provided to the IECC-C Development Committee in advance of the Commentary being published:

• The code shall provide a minimum base energy code with prescriptive and performance-based pathways that take into consideration feasibility of technology and costs impacts to building owners and occupants. The code also provides ANSI/ASHRAE/IES Standard 90.1 as a compliance method.
• The IBC Chapter 13 will continue to reference the IECC Commercial provisions and the IECC shall continue to be referenced in Chapter 13 of the International Building Code.
• Provisions of the code shall not promote or penalize specific types of equipment or fuel sources.
• The code will aim to simplify code requirements to facilitate the code’s use and compliance rate. The code is updated on a three-year cycle with each subsequent edition providing increased energy savings over the prior edition.
• This code is intended to provide flexibility to permit the use of innovative approaches and techniques to achieve this intent. This code is not intended to abridge safety, health or environmental requirements contained in other applicable codes or ordinances.
• Provisions that provide for greenhouse gas reductions or resilience benefits (e.g., electric vehicles, readiness, demand response, and onsite or off-site energy storage or renewable energy) as well as provisions to achieve zero energy buildings shall only be included either in an optional appendix/appendices or as part of a compliance path (e.g., credits system, simulated performance) where compliance is still possible without using or promoting such measures (e.g., through strictly energy efficiency measures).
  • Exception: Current provisions in the 2024 IECC regarding mandatory requirements for renewable energy (section C405.15) may remain in the body of the code as mandatory and may be amended so long as such amendments do not exceed existing requirements.

Residential | Scope & Intent

R101.2 Scope.

This code applies to the design and construction of new and existing detached one- and two-family dwellings and multiple single-family dwellings (townhouses) and Group R-2, R-3 and R-4 buildings three stories or less in height above grade plane, including additions, alterations, repairs and changes of occupancy and use.

R101.3 Intent.

The purpose of the International Energy Conservation Code-Residential is to provide market-driven, enforceable requirements that achieve a reasonable level of energy efficiency that is safe, technologically feasible, and life cycle cost effective, considering economic feasibility, including potential costs and savings for consumers and building owners, and return on investment. Requirements contained in the code will include prescriptive and performance-based compliance options. The IECC residential provisions shall include an update to Chapter 11 of the International Residential Code. The code will provide for the safe and efficient use of energy sources and is not intended to eliminate any fuel type.

The code may include non-mandatory provisions incorporating additional energy efficiency and greenhouse gas reduction resources and provisions that lead to achievement of zero energy buildings. Such provisions shall either be (i) in optional appendices or (ii) in the base code provided as options where compliance with the code is still possible without complying with those provisions. This code’s intent statement does not require the exclusion of provisions contained in prior editions of this code.

Residential | Commentary

The ICC Board of Directors provides the following additional commentary to be written in the IECC Commentary and provided to the IECC-R Development Committee in advance of the Commentary being published:

• The code shall provide a minimum base energy code with prescriptive and performance-based pathways that take into consideration feasibility of technology and costs impacts to building owners and occupants.
• The IECC Residential Provisions shall continue to be coordinated with Chapter 11 of the International Residential Code.
• Provisions of the code shall be based on improved energy performance, such as through energy efficiency ratings or demonstrated simulation model performance and remain neutral to fuel source and do not promote or penalize specific types of equipment or fuel sources.
• The code will aim to simplify code requirements to facilitate the code’s use and compliance rate. The code is updated on a three-year cycle with each subsequent edition providing increased energy savings over the prior edition.
• This code is intended to provide flexibility to permit the use of innovative approaches and techniques to achieve this intent. This code is not intended to abridge safety, health or environmental requirements contained in other applicable codes or ordinances.
• Provisions that provide for greenhouse gas reductions or resilience benefits (e.g., electric vehicles, readiness, demand response, and onsite or off-site energy storage or renewable energy) as well as provisions to achieve zero energy buildings shall only be included either in an optional appendix/appendix or as part of a compliance path (e.g., credits system, simulated performance) where compliance is still possible without using or promoting such measures (e.g., through strictly energy efficiency measures).