State Code Adoption Tracking Analysis

The U.S. Department of Energy (DOE) Building Energy Codes Program reviews adoption of energy codes for residential and commercial buildings. State adoption is reviewed based on the national model energy codes–the International Energy Conservation Code (IECC) for residential buildings and Standard 90.1 for commercial buildings (42 USC 6833). DOE analyzes state energy codes to assess the savings associated with code updates. The resulting findings aid model code adoption, and serve as a means of supporting states working to update their energy codes.

State Analysis

Pacific Northwest National Laboratory (PNNL) conducts state-level technical analysis based on a methodology established by DOE. PNNL reviews state energy codes based on the IECC and Standard 90.1, including any significant amendments. This helps states understand how their codes compare to the national model codes and provides a portrait of national code adoption.

A quantitative analysis is performed to assess the energy savings impacts within a given state, resulting in an energy index. For residential, the Energy Index represents the ratio between the whole-building site energy intensity of a state code and that of the 2006 IECC. The underlying energy use intensities (kBtu/ft2-yr) are derived from per-dwelling unit intensities (kBtu/unit-yr) which are aggregated across building types, foundation types, system types, and climate zones using weighting factors based on new-housing permits. For commercial, the Energy Index represents the ratio between the whole-building site energy intensity of a code and that of 90.1-2004. The underlying energy use intensities (kBtu/ft2-yr) are derived from per-building intensities (kBtu/building-yr) which are aggregated across building types and climate zones using weighting factors based on new-building permit data.

This comparison allows for a categorization of each state, with categories based on recent editions of the model codes. Any code for which the Energy Index is not more than 1% higher than that of an IECC or Standard 90.1 edition is considered equivalent to that code edition. For states whose codes fundamentally differ from the national model codes, PNNL may consider analysis conducted by others as a basis for its categorization.

Why not show EUI directly instead of an Energy Index relative to the 2006 IECC? There are two primary reasons. First, the Index value is easier to interpret because it directly shows relative performance (i.e., as a fraction or percentage of the 2006 baseline). Second, the EUI values tend to change a bit from year to year (or quarter to quarter) due to improvements in the EnergyPlus simulation tool, bug fixes in DOE's simulation infrastructure, updated site-source conversion factors, differences in construction weighting factors, etc. Index ratios between a given code and the 2006 IECC tend to change much less in such situations, so they avoid the appearance of a state code's performance changing when the state didn't change its code.

In an effort to simplify the maps, the categories were changed and no longer include “between categories” (e.g., Between 90.1-2010 and 90.1-2013) or the words “or equivalent”. The current residential categories include: No statewide code, < 2009 IECC, 2009 IECC, 2012 IECC, 2015 IECC, and 2018 IECC. The current commercial categories include: No statewide code, < 90.1-2007, 90.1-2007, 90.1-2010, 90.1-2013, and 90.1-2016. With the implementation of these changes, several states now fall into different categories than in previous maps.

Table 1. Status of State Energy Code Adoption Map Summary - Commercial
State Current Code
(as of 9/30/20)
State Map Legend
(as of 9/30/20)
Alabama 90.1-2013 90.1-2013
Alaska None statewide No statewide code
Arizona* Home rule < 90.1-2007
Arkansas 2009 IECC and 90.1-2007 90.1-2007
California 2016 Building Energy Efficiency Standards 90.1-2016
Colorado Home Rule No statewide code
Connecticut 2015 IECC and 90.1-2013 90.1-2010
Delaware 2018 IECC and 90.1-2016 90.1-2013
District of Columbia^ 90.1-2013 90.1-2016
Florida^ 2015 IECC and 90.1-2013 90.1-2013
Georgia^ 2015 IECC and 90.1-2013 90.1-2013
Hawaii* Home rule < 90.1-2007
Idaho 2015 IECC and 90.1-2013 90.1-2010
Illinois 2018 IECC and 90.1-2016 90.1-2013
Indiana 90.1-2007  90.1-2007
Iowa 2012 IECC and 90.1-2010 90.1-2007
Kansas Home rule No statewide code
Kentucky 2012 IECC and 90.1-2010 90.1-2007
Louisiana 90.1-2007 90.1-2007
Maine 2009 IECC and 90.1-2007 < 90.1-2007
Maryland 2018 IECC and 90.1-2016 90.1-2013
Massachusetts^ 2015 IECC and 90.1-2013 90.1-2016
Michigan^ 2015 IECC and 90.1-2013 90.1-2013
Minnesota^ 2018 IECC and 90.1-2016 90.1-2010
Mississippi None statewide No statewide code
Missouri Home rule No statewide code
Montana 2012 IECC and 90.1-2010 90.1-2007
Nebraska 2018 IECC and 90.1-2016 90.1-2013
Nevada 2018 IECC and 90.1-2016 90.1-2013
New Hampshire 2015 IECC and 90.1-2013 90.1-2010
New Jersey 90.1-2016 90.1-2016
New Mexico 2009 IECC and 90.1-2007 < 90.1-2007
New York^ 2018 IECC and 90.1-2016 90.1-2016
North Carolina^ 2015 IECC and 90.1-2013 90.1-2010
North Dakota Home rule No statewide code
Ohio 2012 IECC and 90.1-2010 90.1-2007
Oklahoma 2006 IECC and 90.1-2004 < 90.1-2007
Oregon 90.1-2016 90.1-2016
Pennsylvania 2015 IECC and 90.1-2013 90.1-2013
Rhode Island^ 2015 IECC 90.1-2010
South Carolina 2009 IECC and 90.1-2007 90.1-2007
South Dakota Home rule No statewide code
Tennessee 2012 IECC and 90.1-2010 90.1-2007
Texas 2015 IECC and 90.1-2013 90.1-2013
Utah 2018 IECC and 90.1-2016 90.1-2013
Vermont^ 2018 IECC and 90.1-2016 90.1-2016
Virginia 2015 IECC and 90.1-2013 90.1-2013
Washington 2015 Washington State Energy Code 90.1-2013
West Virginia 90.1-2010 90.1-2010
Wisconsin^ 2015 IECC and 90.1-2013 90.1-2010
Wyoming Home rule No statewide code

*A review of the codes in place in jurisdictions across the state indicates that 86% (Hawaii) and 82% (Arizona) of the population is covered by codes at this level.

^ When an amendment impacting energy efficiency can be quantified using DOE Prototype Building Models, they were captured in the analysis.

Note:

  1. A home rule state is one where codes are adopted and enforced at the local level. Some home rule states will have a mandate that jurisdictions can go above code but also have to meet a certain minimum code. In general terms, the idea of home rule is defined as the ability of a local government to act and make policy in all areas that have not been designated to be of statewide interest through general law, state constitutional provisions, or initiatives and referenda.
  2. States with extensively different baseline codes for which conducting custom analysis would be cost prohibitive and out of scope of this analysis.
  3. For states adopting both IECC and 90.1, the IECC code is analyzed as the state current code in this study.

 

Table 2. Status of State Energy Code Adoption Map Summary - Residential
State State Current Code
(as of 9/30/20)
State Map Legend
(as of 9/30/20)
Alabama 2015 IECC with amendments 2009 IECC
Alaska None statewide No statewide code
Arizona* Home rule < 2009 IECC
Arkansas 2009 IECC with amendments < 2009 IECC
California 2019 Bldg. Energy Efficiency Standards 2018 IECC
Colorado Home rule No statewide code
Connecticut 2015 IECC with amendments 2009 IECC
Delaware 2018 IECC  2018 IECC
District of Columbia 2015 IECC with amendments 2018 IECC
Florida 2015 IECC with amendments 2018 IECC
Georgia 2015 IECC with amendments 2009 IECC
Hawaii* Home rule < 2009 IECC
Idaho 2012 IECC with amendments 2009 IECC
Illinois 2018 IECC with amendments 2009 IECC
Indiana 2018 IECC with amendments 2009 IECC
Iowa 2012 IECC with amendments 2009 IECC
Kansas Home rule No statewide code
Kentucky 2009 IECC 2009 IECC
Louisiana 2009 IECC 2009 IECC
Maine 2009 IECC 2009 IECC
Maryland 2018 IECC 2018 IECC
Massachusetts 2015 IECC with amendments 2015 IECC
Michigan 2015 IECC with amendments 2009 IECC
Minnesota 2012 IECC with amendments 2009 IECC
Mississippi None statewide No statewide code
Missouri Home rule No statewide code
Montana 2012 IECC with amendments 2009 IECC
Nebraska 2018 IECC 2018 IECC
Nevada 2018 IECC with amendments 2009 IECC
New Hampshire 2015 IECC with amendments 2009 IECC
New Jersey 2018 IECC with amendments 2009 IECC
New Mexico 2009 IECC 2009 IECC
New York 2018 IECC with amendments 2018 IECC
North Carolina 2015 IECC with amendments 2009 IECC
North Dakota Home rule No statewide code
Ohio 2018 IECC with amendments 2009 IECC
Oklahoma 2009 IECC with amendments 2009 IECC
Oregon 2017 Oregon Residential Specialty Code  2018 IECC
Pennsylvania 2015 IECC with amendments 2009 IECC
Rhode Island 2015 IECC with amendments 2009 IECC
South Carolina 2009 IECC 2009 IECC
South Dakota Home rule No statewide code
Tennessee 2009 IECC with amendments < 2009 IECC
Texas 2015 IECC 2018 IECC
Utah 2015 IECC with amendments 2009 IECC
Vermont 2018 IECC with amendments 2018 IECC
Virginia 2015 IECC with amendments 2009 IECC
Washington 2015 Washington State Energy Code 2018 IECC
West Virginia 2009 IECC 2009 IECC
Wisconsin 2009 IECC with amendments 2009 IECC
Wyoming Home rule No statewide code

*A review of the codes in place in jurisdictions across the state indicates that 86% (Hawaii) and 82% (Arizona) of the population is covered by codes at this level.

Available Data

The state-level results behind the DOE adoption status maps are available for commercial & residential buildings:

Commercial

Residential

More information on DOE support for state code adoption and other forms of technical assistance.