February 28, 2005

WASHINGTON, D.C. -- The American Council for an Energy-Efficient Economy (ACEEE) today released its analysis of the energy and dollar savings that will stem from efficiency improvements in the 2004 International Energy Conservation Code (IECC). These improvements increase the efficiency standards for walls in new homes. ACEEE found that over a 30-year period, these improvements will save about 500 Trillion Btu and more than $7 billion in homeowner energy bills. This is about the amount of energy used by all home air conditioning systems annually. Impact Assessment of 2004 IECC Wall Criteria Changes is available for free download.

These improvements are also cost-effective on a life-cycle basis, saving more in reduced energy bills than they may cost in added construction costs. In fact, because the IECC allows flexible compliance options, this level of efficiency improvement can be achieved in various ways, potentially at little or no added construction cost.

"Homebuyers today face the highest heating costs in American history. The IECC must respond by increasing new home efficiency standards," said ACEEE Deputy Director Bill Prindle. "These modest IECC improvements are one small, cost-effective step for affordable housing and a sustainable energy future."

ACEEE used the nationally recognized REM-Rate computer simulation model to calculate the energy savings in a variety of home designs in nine representative cities. ACEEE collected data from insulation contractors and other sources on upgrade costs and adjusted them for future market conditions, and employed the National Institute of Standards and Technology (NIST) life-cycle-costing method for the economic analysis.

A similar study by the U.S. Department of Energy (DOE), using computer simulation and life-cycle-cost methods, found energy and cost savings very similar to those produced in the ACEEE analysis. Both studies also found that there are cost-effective insulation solutions to the new IECC standards. However, some parties, who opposed the original improvements, have sought to interpret the DOE study data as showing that these improvements are not cost-effective. ACEEE disagrees with these interpretations, because they use worst-case assumptions and do not acknowledge that flexible compliance options allow builders to trade off the wall upgrades against other building components and systems.