News Brief

Changes Finalized for 2015 Energy Code

The 2015 IECC applies to historic buildings and offers a performance path based on the HERS Index.

The IECC energy code will have more of an impact on the nation's aging building stock and will realize greater energy savings now that historic buildings are no longer automatically exempted.

Photo: Randolph Historic District, New York. License: Doug Kerr CC BY 2.0.

Hearings to settle proposals for the 2015 International Energy Conservation Code (IECC)—the code that serves as the model for states and localities across the country—have ended, finalizing some marked differences from the 2012 version.

One of the biggest changes eliminates the code’s blanket exemption of historic buildings. In the latest version, energy standards do apply to both residential and commercial historic buildings, and a report detailing why a provision is detrimental to the historic character of the building is required for exceptions.

Another approved change in the residential code adds a performance path for compliance based on the HERS Index. Instead of basing performance on energy costs—limited to heating, cooling, and water heating—the new path requires that homes achieve a HERS score between 51 and 55, depending on the climate zone; HERS is already widely used and accounts for energy use from lighting and appliances, too.

Reinstating mechanical equipment tradeoffs, one of this year’s highly controversial proposals, was defeated, and a measure requiring builders to dedicate roof space and install chase wiring to ensure that all new homes are “solar-ready” fell short of passage by one vote, but may indicate where the code could go next.

The code is updated every three years, but states are just beginning to adopt the 2012 version and, according to, the 2015 version is not likely to be published until 2014.


Published December 2, 2013

Pearson, C. (2013, December 2). Changes Finalized for 2015 Energy Code. Retrieved from

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