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RESNET Submits ’24 IECC Proposal To Significantly Increase ERI Option Use

Oct 21, 2021

RESNET has submitted a code change proposal to the International Energy Conservation Code (IECC) residential committee to address the barriers to builders using the Energy Rating Index (ERI) (Section 406) option of the IECC.

There have been significant efforts over many code cycles to chip away at the viability of the performance paths in the IECC. Unfortunately, many of these efforts have been successful. The performance compliance options in the IECC (R405 and R406) are meant to be performance options. Their purpose is to allow builders’ some flexibility in how they achieve a given performance target. Ultimately, that performance target should serve as the indicator of achieving compliance. It is also worth noting that these two compliance paths necessitate hiring a professional (HERS Rater, energy modeling professional, etc.) to use an energy modeling software to verify compliance. The ERI path is the one compliance option in the IECC capable of demonstrating net-zero energy compliance. However, it is not possible to achieve net-zero energy construction without the use of renewable energy. This should be kept in mind when setting net-zero policy because not all building types or building sites are suited for on-site renewable energy. When considering maximizing efficiency prior to the implementation of on-site renewable energy, an ERI score from the low 30’s (northern climates) to the low 40’s (southern climates) is typically as low as a builder can get with efficiency measures alone.

To address the barriers to the viability of the ERI option RESNET has proposed the following:

1.  Delete the 5 percent additional energy efficiency package requirement in section R401.2.5. The ERI is already the most stringent compliance option, so this added 5 percent efficiency is unnecessary. If it’s the consensus of the committee that this 5% improvement is necessary, then RESNET recommends revising the ERI targets in Table R406.5 accordingly.

2.  Delete Sections R406.3.1 and R406.3.2 and revise Section R406.3 to create a single minimum building thermal envelope requirement based on the 2018 IECC prescriptive tables. The current requirements for a changing building thermal envelope baseline, based on the presence of renewable energy are confusing and unnecessary.

3.  Revise Section R406.4 to eliminate Equation 4-2 and the language for changing the reference home ventilation rate. The original proposal that added this change into the 2018 IECC was misguided and did not have the intended effect.

4.  Revise Section R406.4 to delete the last sentence which limits the impact of on-site renewable energy to 5 percent of total energy use. By implementing a minimum building thermal envelope requirement, based on the 2018 IECC levels, as described in #2 above, this arbitrary 5 percent limitation on renewable energy is unnecessary.

The next step in the process of adopting the 2024 IECC is the consideration of proposed amendments by the International Code Council’s Residential Energy Code Consensus Committee, which is responsible for the 2024 update of the IECC.  The consensus committee has 48 members.  There are ten members of the committee that are either members of the RESNET Board, HERS® Raters, or members of RESNET’s committees.

For more information on the process for developing the updates, click on 2024 IECC