Dear Members of the Residential Energy Code Consensus Committee,
In early 2021, the process to update the International Energy Conservation Code was changed from a governmental consensus process to a standards process. ICC’s Path Forward on Energy and Sustainability to Confront a Changing Climate provided reassurance to governmental members that they would “continue to have a leading voice” in the process, “recognizing the important role of governments in the adoption and use of the IECC”. Based on this promise, and the important historical role that governmental members have always played in the development of the IECC, we, the undersigned governmental members and supporting organizations are writing to express our concerns about the 2024 Residential IECC. We believe that any changes that weaken aspects of the 2021 code undermine our earlier votes, and should not be included in the 2024 draft.
With that in mind, we submit the following commentary and support any proposed language changes that align with these statements:
Ceiling insulation requirements. Changes to Tables R402.1.2 and R402.1.3 in the first public comment draft of the 2024 Residential IECC roll back the ceiling insulation values to that of the 2018 IECC, values that had remained the same since 2012. This is inconsistent with the ICC Board’s repeated assurances that the 2021 IECC would be the starting point for future editions of the code. We believe the values listed in the 2024 version of the code should not be made less stringent than those voted upon in the 2021 development cycle.
Performance path equipment efficiency trade-offs. The equipment trade-offs incorporated into Table R405.4.2(1) via the changes to the standard reference design should be removed. The Residential IECC has not allowed fossil fuel equipment efficiency to be traded off in the performance path since 2009. The first public review draft’s inclusion of these trade-offs marks another step backwards from the 2021 IECC. Given the large gap between federal minimum efficiencies and the efficiencies of commonly-installed equipment, setting the reference design at federal minimums creates an artificial “credit” for proposed home designs that will be used to reduce the overall efficiency of homes. By allowing reductions in the efficiency of elements of the building envelope in exchange for perceived increased efficiency in heating, cooling, and water heating equipment, the long-term benefits of an efficient envelope are sacrificed for building components with a significantly shorter life span. Equipment trade-off proposals have been defeated by the voting members in each of the last five code development cycles, most recently in the 2021 development cycle where similar provisions were rejected both by the committee and by 91% of Governmental Member Voting Representatives.
Additional efficiency requirements equipment trade-offs. Section R408.2.9 permits a more lenient U-factor to be used for wood frame walls in exchange for installing heat pumps or renewables, or increasing the number of efficiency credits achieved. In contrast to equipment or even renewable energy resources, the building envelope will likely remain untouched for much of the life of the building, and, as with the performance path changes listed above, trade-offs at the time of construction may saddle the future building occupants with a less resilient structure and increased energy bills.
Duct location trade-offs. Table R405.4.2(1) now sets the duct location in the standard reference design as partially located outside conditioned space, creating a credit in the performance path (where there was no credit previously) for the location of ducts in conditioned spaces. Although locating ducts inside conditioned space is an efficient building practice, this “credit” will serve to reduce the efficiency of other building components. Ducts are often already located within conditioned space—particularly in heating-dominated climate zones—and credit should not be provided for measures already commonly installed. We propose to return the standard reference design to be the same as the proposed design for this element of construction.
Per the following graph from the Pacific Northwest National Laboratory (PNNL), the residential energy code will need to continue to make significant improvements in order to achieve net zero new construction by 2030—a goal critical to local, national, and global climate outcomes. This deadline leaves only the 2024 and the 2027 model code development cycles in which to make that change, meaning we cannot afford to start with anything less than the 2021 code.
Jurisdictions throughout the US and beyond rely on ICC for the development of a model energy code suited to continued improvements in home energy efficiency, reduction in household energy costs, and achieving our collective climate goals. We urge the Residential Consensus Committee to reject any code language that moves us away from achieving those goals, and to respect the votes that achieved the 2021 Residential IECC.