Research: Cost Analysis of the 2009 and 2012 International Energy Conservation Code

Many states have started adopting the 2009 International Energy Conservation Code (IECC), which contains significant changes over the prior version—the 2006 IECC. The just-released 2012 edition, which includes even more aggressive changes and significant administrative differences, is also being vetted for adoption.

If adopted on the local level, these codes will require meaningful changes in the ways apartment buildings are designed and constructed. Depending on the geographic region and the version of the code adopted, they could also add several thousand dollars to the cost of each apartment unit.

This report, Impact of the 2009 and 2012 International Energy Conservation Code in Multifamily Buildings,  offers a detailed comparison of the 2009 and 2012 IECCs compared to the 2006 edition. It breaks out these costs for a typical low-rise property and a typical high-rise property by climate zone. The research was conducted by Niles Bolton Associates, Inc., an architecture and engineering firm specializing in apartments.

It is designed to aid member firms in preparing for upcoming code requirements where the more stringent codes are adopted. It is also developed to be a tool for local apartment advocates to help local jurisdictions understand the real implications adopting these codes will have on housing costs in their localities. NMHC/NAA will be using this research as part of our federal-level advocacy efforts to oppose onerous building energy codes that are not cost-effective or technically feasible.

Key Resources

  • Full Report
  • Summary: Compliance Costs by Property Type and Climate Zone
  • Zone 1: Florida, Hawaii
  • Zone 2: Alabama, Arizona, California, Florida, Georgia, Louisiana, Mississippi, Texas
  • Zone 3: Alabama, Arizona, Arkansas, California, Georgia, Louisiana, Mississippi, Nevada, New Mexico, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Utah
  • Zone 4: Arizona, Arkansas, California, Colorado, Delaware, District Of Columbia, Georgia, Illinois, Indiana, Kansas, Kentucky, Maryland, Missouri, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Tennessee, Texas, Virginia, West Virginia
  • Zone 5: Arizona, California, Colorado, Connecticut, Idaho, Illinois, Indiana, Iowa, Kansas, Maryland, Massachusetts, Michigan, Missouri, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah, Washington, Wyoming
  • Zone 6: California, Colorado, Idaho, Iowa, Maine, Michigan, Minnesota, Montana, New Hampshire, New York, North Dakota, Pennsylvania, South Dakota, Utah, Vermont, Washington, Wisconsin, Wyoming
  • Zone 7: Alaska, Colorado, Maine, Michigan, Minnesota, North Dakota, Wisconsin, Wyoming
  • Zone 8:

For more Climate Zone resources, including information about Climate Zones by county, see

Key Findings

In general, the IECC is moving toward a heavy emphasis on building insulation and building envelope construction. Our analysis shows there are considerable differences between compliance costs for the 2009 and 2012 codes as well as significant cost variance between low-and high-rise properties across climate zones. Notably, these cost differentials are not consistent across, or between, the code editions. Key findings of the new energy code research include:

  • In a moderate climate zone, compliance costs for the 2009 and 2012 codes will range between $760 and $3,590 per apartment unit in a low-rise building, and soar to $1,860 and $4,440 per unit in a high-rise project. 
  • The 2009 IECC will be most affordable for high-rise buildings in warmer climate zones–costing approximately $90-$140 per apartment unit. In cooler climates, however, the cost increases for high-rise properties range from $940 to a whopping $3,410 per unit, depending on the specific building location and design characteristics.
  • The costs to comply with the 2012 code are even more extreme. A low-rise building in the two warmest climate zones (Zones 1 and 2) will be required to spend an additional $480-$720 per apartment unit. Projects in the next two warmest zones (Zones 3 and 4) will spend a minimum of $1,820-$2,160 more per unit.

If you have any questions about the report or new building code initiatives, please contact Ron Nickson at or 202-974-2327.