Several municipalities and counties in Northern Nevada recently joined states around the nation by adopting the 2015 IECC Energy Rating Index (ERI) compliance option. The state’s current residential energy code – the 2012 IECC – is still in effect, but has been amended in these locations to include an ERI compliance path and a 2009 IECC thermal envelope backstop.
With the 2018 version of the IECC being developed this year, it seems appropriate to look at the success of the ERI and what the future may hold. The voluntary ERI path for the 2015 IECC gives builders the option of complying with the code by meeting a target Energy Rating Index score. This is a numerical score where 100 equates to the efficiency levels prescribed in the 2006 IECC and 0 is equivalent to a net-zero-energy (NZE) home.
Looking at what makes the 2015 IECC different from the 2012 version, the biggest change that will affect builders is the addition of an Energy Rating Index (ERI) compliance path. This article will outline some other important changes. Five of the major changes in the 2015 IECC that will affect new home construction include specifying required inspections; revised requirements for vertical access doors; a new requirement for combustion closets; revisions to the building envelope air leakage testing requirements; and revised requirements for duct insulation.
The Pacific Northwest National Laboratory analyzed the relationship between the Residential Energy Services Network (RESNET) Home Energy Rating System (HERS) Index and the traditional simulation-based Performance Path used in the International Energy Conservation Code (IECC). These findings will be important to be aware of as states and municipalities begin to consider adoption of the 2015 IECC, which includes a HERS-like rating system as an alternative compliance path.