National model energy codes are developed and published on a three-year cycle. The two most widely adopted energy codes are the International Energy Conservation Code (IECC) and ASHRAE’s Energy Standard for Buildings Except Low-Rise Residential Buildings (ASHRAE 90.1).
After an energy code is published (IECC for residential and ASHRAE 90.1 for commercial and multifamily above three stories in height), the Department of Energy compares the latest edition of the code to the previous edition to determine if the code has become more energy efficient. A positive determination by DOE triggers a series of requirements that are outlined in the DOE Determinations State Certifications Fact Sheet.
When a state or jurisdiction goes through the adoption process for an energy code, there are typically public hearings and an opportunity to amend the code prior to adoption. NAHB has developed a series of adoption kits that include highlights of changes from the previous code, associated cost increases and a list of suggested amendments that offer more cost-effective and affordable energy conservation code provisions than available in the model codes.
Log Homes and Energy Code
More stringent provisions in the 2012 and 2015 energy codes have made it increasingly difficult for log homes to meet requirements. These are code amendments that help fix problems created in the IECC that would otherwise significantly increase the construction cost of log homes.
- Log Home Energy Performance White Paper
- Proposed Amendment to the 2018 IECC
- New Hampshire Amendment
- Michigan Log Home Legislation
- Michigan Log Home Legislation (Analysis)
- Pennsylvania Amendment
- New York Amendment
Energy Code Adoption Cost Analysis
These cost studies quantify the economic impact of adopting specific energy codes and include the methodology used.
- Energy Code Percent Savings Calculation Methodology (White Paper)
- 2009 Cost Savings Analysis
- 2012 IECC Cost and Energy Savings Analysis
- NMHC Multifamily Methodology and Cost Charts
- NMHC 2009 to 2012 Cost Study Cost Study Charts
A U.S. Department of Energy (DOE) determination is a statute mandated by the Energy Conservation and Production Act for the DOE to review the most recently published energy efficiency codes. Once reviewed, the agency makes their determination on whether the newly published code is more energy-efficient than its predecessor. Below are DOE determinations for the 2015, 2012, and 2009 IECC codes.
DOE also released a determination on Feb 21, 2018 that ANSI/ASHRAE/IES Standard 90.1-2016 will improve the energy efficiency in commercial buildings. Read more here.
Most states adopt a statewide energy code that is an amended version of a national model code. This Adoption Summary Spreadsheet lists the current energy code in place for each state and describes the key amendments that were made to the model code along with a link to the amended version of the code.