MBPE clears residential energy‑code proposals for council; ERI path, home‑size credits and PV/storage drew heated debate

The MBPE committee voted on July 18 to forward the residential energy‑code proposals to the Building Code Council, approving a package that includes a new Energy Rating Index (ERI) pathway, revised home‑size credit bands, an updated baseline fenestration U‑value and several related clarifications.

What the package would do: The tag added a new ERI pathway (an energy‑rating, HERS‑style approach) as an alternate compliance path to the existing prescriptive and modeling routes. The tag also revised how home sizes map to credit requirements: it smoothed the jump between size bands to avoid a large credit increase when a home crosses a single square‑foot threshold and created contingency credit levels depending on whether the council also adopts two tied edits (a 0.27 fenestration U‑value and a 3 ACH air‑leakage limit).

Modeling and scope: Unlike the commercial C406 modeling contract, the tag did not commission third‑party modeling to update the R406 credits; PNNL and NIA were working on modeling for the modeling pathway (R405) and ERI, but…