2024 IECC Code Change Proposal Synopsis

Below you will find summaries of the draft code amendments and links to revision details that were submitted by NBI into the ICC process to advance the 2024 IECC. They are identified as Commercial or Residential and categorized by efficiency, renewable energy, electrification, grid integration, existing buildings, or zero energy home. Each item provides a brief code change title, the section of the code that could be impacted in brackets, a proposal number, summary, and link to more detail.

Commercial Proposals Residential Proposals

 

Detailed code language and brief reason statements are also available in this printer-friendly document.

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Summaries of the Draft Code Amendments

Commercial

Efficiency

Cool Roof Expansion [C402] CEPI-50-21
Increases SRI requirement for Climate Zones 0-3 and establishes requirements for cool roofs in CZs 4 and 5.

Air Barrier Testing [C402] CEPI-58-21
Increase building size threshold for testing to 250,000 ft2 and reduce allowable air leakage rate to 0.25 cfm/ft2.

Dedicated Outdoor Air Systems (DOAS) [C403] CEPI-98-21
Requires commercial buildings to install a DOAS system, separating ventilation from space conditioning.

Horticultural Dehumidification [C403] CEPI-84-21
Increases the efficiency of dehumidification systems in horticultural applications.

Horticultural Lighting[C405] CEPI-185-21 – APPROVED
Increases stringency for lighting in horticultural applications.

Energy Monitoring [C405] CEPI-138-21
Reduces size threshold for energy monitoring requirement to 10k sqft to align with common benchmarking policies.

Energy Monitoring for EVs[C405] CEPI-140-21
Requires submetering for EVs where installed.

Commissioning [C408] CEPI-215-21 – APPROVED
Reduces thresholds for required commissioning of systems.

Multifamily Alignment Multiple CEPI-53-21
Aligns requirements for multifamily buildings across commercial and residential provisions.

Renewable Energy

Biomass [C202] CEPI-12-21 Part 1 – APPROVED
Clarifies the type of biomass that counts as a renewable energy resource.

Onsite Renewable Energy [C405] CEPI-5-21
Requires on-site renewable energy generation.

Renewables Definition Appendix CC CEPI-248-21
Clarifies renewable energy terms in Appendix CC.

Energy Storage Ready CEPI-7-21
Makes energy storage ready requirements mandatory for all buildings.

Electrification

Commercial Decarbonization [C402] CEPI-22-21
Requires all new construction be all-electric.

Grid Integration

Grid Integrated Thermostats [C403] CEPI-99-21
Requires grid-integrated controls on space heating and cooling systems that adjust temperature within 4-degrees.

Grid Integrated Water Heating [C404] CEPI-125-21
Requires grid-integrated controls on electric storage water heaters (37-120 gallons/ “residential style”).

Electric Vehicles [C405] CEPI-146-21 Part I
Requires EV charging for all commercial building types. Energy Storage Ready C405 Requires commercial and multifamily energy storage readiness.

Solar and Storage Inverters [C405] CEPI-142-21 – APPROVED
Requires solar and energy storage systems be equipped with smart inverters for grid-integrated controls.

Grid Optimal Credits [C406] CEPI-197-21
Establishes credits for buildings to shed load during peak demand hours.

Existing Buildings

Additional Efficiency Credits for Existing Buildings [C506] CEPI- 217-21
This proposal adds a requirement that additions and large alterations achieve a minimum level of points from C406 through the addition of a new Section C506.

Acceptance Testing for Alterations [C503] CEPI-229-21
Requires acceptance testing of existing HVAC, SHW or lighting systems that serve alterations.

HVAC Control Upgrade in Alterations [C503] CEPI-231-21
New HVAC equipment in alterations must have controls that comply with current code requirements.

Lighting Control Upgrades in Alterations [C503] CEPI-231-21
New luminaires in alterations must have lighting controls that comply with current code requirements.

Duct Leakage Testing in Alterations [C502] [C503] CEPI-219-21
Ducts must be tested when equipment is replaced.

System Sizing in Commercial Alterations [C503] CEPI-228-21
New equipment installed in alterations has to be right sized based on the alteration.

Testing of Gas Piping in Alterations [C502] [C503] CEPI-218-21 Part I
When new gas equipment is installed, the gas piping has to be leakage tested.

Residential

Efficiency

Multifamily Alignment [Multiple]
Aligns requirements for multifamily buildings across commercial and residential provisions.

Efficiency Credits [R408]
Changes residential option packages to a credit-based structure similar to Commercial C406.

Renewables

Biomass Waste Definition [R202] CEPI-12-21 Part 2
Adds definition of biomass waste and clarifies definition of renewable energy resources.

Solar Readiness [R404]
Requires single- and two-family solar readiness. Requires multifamily to comply with a sister provision under commercial section of energy code.

Renewable Energy Credits [R404] REPI-158-21
Clarifies RECS definition and documentation requirements for RECS. Electrification

Residential Decarbonization [R202]
Requires all new construction be all-electric.

Grid Integration

Grid Integrated Water Heating [R403]
Requires grid-integrated controls on electric storage water heaters (37-120 gallons/ “residential style”).

Grid Integrated Thermostats [R403]
Requires grid-integrated controls on space heating and cooling systems that adjust temperature within 4-degrees.

Solar and Storage Invertors [R404]
Requires solar and energy storage systems be equipped with smart inverters for grid-integrated controls.

Electric Vehicles [R404] CEPI-146-21 Part II
Requires single- and two-family EV charging. Requires multifamily to comply with a sister provision under commercial section of energy code.

Energy Storage Readiness [R404]
Requires single- and two-family energy storage readiness.

Zero Energy Home

Zero Energy Home Appendix Update [Appendix RC]
Updates the Zero Energy Home Appendix with ERI targets based on a survey of Passive House scores

Zero Energy Home Appendix Decarbonization [Appendix RC]
Updates the Zero Energy Home Appendix to require all-electric construction.

Zero Energy Home Appendix Renewable Definitions [Appendix RC] REPI-161-21
Clarifies renewable energy terminology used in the Zero Energy Home Appendix.

Existing Buildings

Additional Efficiency Packages for Existing Buildings [R506] REPI-144-21
This proposal adds a requirement that large additions and large alterations include a package option from R408.

HVAC Control Upgrade in Alterations [R503] REPI-152-21 – APPROVED
New HVAC equipment in alterations must have controls that comply with current code requirements.

Duct Leakage Testing in Alterations [R502] [R503] REPI-145-21
Ducts must be tested when equipment is replaced.

System Sizing in Residential Alterations [R503] REPI-151-21 – APPROVED
New equipment installed in alterations has to be right sized based on the alteration.

Testing of Gas Piping in Alterations [R502] [R503] CEPI-218-21 Part II
When new gas equipment is installed, the gas piping has to be leakage tested.

Copyright © 2021 New Buildings Institute. Use of New Buildings Institute’s (NBI) Draft Amendments for the development of the 2024 IECC (published October 11, 2021) is permitted on a royalty-free basis. NBI claims no rights in and makes no representations as to the contents or use of the International Energy Conservation Code®. NBI makes no representations as to the suitability of this code language for any purpose, and all content is provided as-is. All other rights reserved.