The Marriage of Residential Energy Codes and Rating Systems: Conflict Resolution or Just Conflict?

摘要

After three decades of coexistence at a distance, model residential energy codes andrnresidential energy rating systems have come together in the 2015 International EnergyrnConservation Code. At the October, 2013, International Code Council’s Public CommentrnHearing, a new compliance path based on an Energy Rating Index was added to the IECC.rnAlthough not specifically named in the code, RESNET’s HERS rating system is the likelyrncandidate Index for most jurisdictions. While HERS has been a mainstay in various beyond-codernprograms for many years, its direct incorporation into the most popular model energy code raisesrnquestions about the equivalence of a HERS-based compliance path and the traditional IECCrnperformance compliance path, especially because the two approaches use different efficiencyrnmetrics, are governed by different simulation rules, and have different scopes with regard tornenergy impacting house features. A detailed simulation analysis of almost 15,000 housernconfigurations reveals a very large range of HERS Index values that achieve compliancernequivalence with the IECC’s performance path. In this paper we summarize the results of thatrnanalysis and, by evaluating those results against the specific Energy Rating Index values requiredrnby the 2015 IECC, find those ERIs to be very similar to the conservative (lower) end of the rangernof HERS values identified as corresponding to compliance with the traditional performance path,rnsuggesting that many if not most homes built to the new ERI path’s requirements would havernbetter energy performance than if built to the traditional performance compliance path. Finally,rnbased on the home characteristics most likely to result in disparities between HERS-basedrncompliance and performance path compliance, potential impacts on the compliance process, staternand local adoption of the new code, energy efficiency in the next generation of homes subject tornthis new code, and future evolution of model code formats are discussed.