Written by Scott Doig, PEA Summer 2024 Intern and Senior at Oberlin College
The Philadelphia C-PACE (Commercial Property Assessed Clean Energy) program requires that new construction and gut rehab projects exceed the minimum energy efficiency code requirements established by Philadelphia’s building energy code. The current code is International Energy Conservation Code (IECC) 2018. Beginning in July 2025, Philadelphia and Pennsylvania will adopt IECC 2021.
This post provides a description of the major differences between IECC 2018 and IECC 2021 for commercial properties.
A recent analysis by the Pacific Northwest National Laboratory (PNNL) indicated that commercial buildings adhering to the IECC 2021 could see energy savings of 4.7 percent compared to IECC 2018.
Key Changes in the IECC 2021 for Commercial Buildings
Building Envelope: The new code mandates higher insulation levels to improve thermal resistance (R factor) and reduce heat transfer (U factor). The updated code requirements for envelope air leakage testing and verification adopted by Pennsylvania requires that the reports be submitted to code officials. Additionally, new provisions mandate controls for operable openings including windows and doors.
Mechanical Systems: The code updates efficiency requirements for mechanical equipment. These include refinements in energy recovery ventilation and introducing a new fan efficiency metric.
Electrical Power and Lighting Systems: The code increases lighting and power efficiency requirements. Pennsylvania made section 405.11 on automatic receptacle control optional. There are also new provisions that mandate energy metering and monitoring.
Efficiency Requirements of Section C406: The revised structure of Section C406 now includes a greater number of additional efficiency options. Buildings must comply with one or more of the following: enhanced HVAC performance requirements, reduced lighting power, improved lighting controls, on-site renewable energy supply, dedicated outdoor air systems for certain HVAC equipment, high-efficiency service water heating systems (hot water for restrooms, showers, kitchens, etc.), enhanced envelope performance, and measures to reduce air infiltration.
Appendices: New appendices are included in IECC 2021 though they were not adopted for use in Pennsylvania, so are optional. They include: (1) Appendix CA Board of Appeals to address disputes related to code interpretation and enforcement; (2) Appendix CB is for Solar-Ready new construction; (3) Appendix CC introduces provisions for zero energy commercial buildings.
Resources: