News Brief

Model Building Code Now 30% More Energy Efficient

Changes made to the International Energy Conservation Code (IECC) will increase the predicted energy efficiency of homes and commercial buildings by 30% over ASHRAE Standard 90.1-2004. Members of the International Code Council (ICC) approved the changes nearly unanimously in October 2010; they will be available for jurisdictions to adopt in April 2011, when the 2012 IECC is published.

Many of the changes relevant to commercial buildings came from a joint proposal developed by the New Buildings Institute (NBI), The American Institute of Architects, and the U.S. Department of Energy. Based on NBI’s Core Performance protocol, the new requirements include the addition of a continuous air barrier, HVAC economizers in more climate zones than in the old code, and lighting control systems that respond to daylight and occupancy needs. For the first time, IECC also requires basic commissioning for building systems to ensure they are running at peak efficiency.

Another package of changes brought by the Energy Efficient Codes Coalition and the Institute for Market Transformation (IMT) updated the residential side of the energy codes. The energy chapter of the International Residential Code was removed and replaced with the residential components of IECC. At the same time, residential requirements in IECC were adjusted to include increased window performance, increased insulation requirements, better duct-sealing measures, and greater lighting efficiency, among other things. The fact that builders will now have to prove airtightness achievement with a blower-door test was particularly controversial.

“The often contentious process of developing codes was largely avoided in this case because of the extensive outreach and collaboration that was undertaken to gain industry support for the proposals,” said Dave Hewitt, NBI executive director. By bringing packages of changes—rather than individual changes—the organizations were able to streamline the code development process and win broad support in the industry.

The result is perhaps the biggest improvement in energy efficiency ever achieved in a single code update. “In the 10 years I’ve been attending ICC code hearings, I have never seen a larger single stride taken for energy efficiency,” said Dick Meyer, building codes program director at IMT.

The advocacy group Architecture 2030 noted that having the code require 30% improvement over ASHRAE 90.1-2004 aligns it with the 2030 Challenge’s 2006 goal of 50% energy savings. This update was approved by code officials, which should improve its chances of adoption by states and local governments, but is no guarantee.

For more information:

New Buildings Institute

Institute for Market Transformation


Published November 9, 2010

Wendt, A. (2010, November 9). Model Building Code Now 30% More Energy Efficient. Retrieved from

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