On March 18, 2024, the International Code Council Board of Directors voted to affirm in part and reject in part nine appeals filed by five appellants to a draft of the 2024 commercial and residential editions of the International Energy Conservation Code® (IECC®). The Board also addressed several claims that aspects of the draft 2024 IECC codes were preempted by the federal Energy Policy and Conservation Act.  

The Appeals 

The appeals were focused on the IECC’s scope and intent, consensus building approaches, procedural specific issues, and subject specific issues. The International Code Council Board of Directors determined that the scope and intent governing the 2024 IECC prohibited the inclusion of measures that did not directly affect building energy conservation within the base of the draft 2024 IECC, as the intent of both the commercial and residential 2024 IECC codes is limited to “providing minimum efficiency requirements for buildings that result in the maximum level of energy efficiency that is safe, technologically feasible, and life cycle cost effective considering economic feasibility, including potential costs and saving for consumers and building owners, and return on investment.” The Board further determined that alternative measures, including measures without direct impacts to building energy conservation, but that may reduce greenhouse gas emissions, could be included as appendix materials given the intent of both the residential and commercial IECC codes provides that “[t]he code may include nonmandatory appendices incorporating additional energy efficiency and greenhouse gas reduction resources.”  

Based on this interpretation, the Board resolved that several challenged provisions that the Board viewed as concerning greenhouse gas reduction and not building energy conservation be removed from within the base of the draft 2024 IECC codes and placed in appendices to accompany the codes. The affected provisions moved to an appendix include:  

  • Sections C406.1.1.1 and C502.3.7.1 (heat pump products)  
  • Sections C403.4.6, C404.10, C405.2.8, R403.5.4 and N1103.5.4 (demand response)  
  • Sections C405.14, R404.7, and N1104.7 (electric vehicle charging infrastructure)  
  • Section C405.16 (electrical energy storage system readiness)  
  • Sections R404.6 and N1104.6 (solar readiness)  
  • Sections R404.5 and N1104.5 (electric readiness)  


The Board also considered concerns voiced by the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) that provisions in the draft IECC codes were federally preempted by the Energy Policy and Conservation Act. Where the Board determined there was a significant risk of preemption based on case law or the Board had concerns about the ability to comply with provisions using minimum efficiency equipment, the Board decided to move those provisions to a resource with a cautionary note regarding the risk of preemption. Affected provisions include:  

  • Appendix CG (all-electric commercial) and Appendix RE (all-electric residential): moved to resource due to significant risk of preemption based on case law 
  • Appendix CD Section CD101.1 and Table CD101.1 (prescriptive glide path to net zero): moved to resource due to significant risk of preemption based on an inability to comply with minimum efficiency equipment  
  • Appendix RG (glide path to net zero): retained as an appendix with a cautionary note regarding the limited compliance options for minimum efficiency equipment in specific climate zones 

 Finalization of the 2024 IECC

The Board’s determinations mark the conclusion of the 2024 IECC’s development and the code’s finalization. The 2024 IECC builds on the 2021 edition and is anticipated to improve energy efficiency by roughly 6.5% for residential buildings and by 10% for commercial buildings. For jurisdictions seeking to incorporate additional greenhouse gas reduction measures, the code will contain new options for electrical vehicle charging infrastructure, energy storage systems, electric readiness, and demand responsive controls. The Code Council deeply appreciates the extensive work of the 2024 IECC development committees and stakeholders who participated in the development process and the subsequent appeals.