State and Local Policy Database

Residential Codes

Mandatory residential building codes require a minimum level of energy efficiency for new residential buildings. The Department of Energy estimates that between 1992 and 2012, residential codes resulted in cumulative energy savings of 1.8 quads. They project that an additional 21.2 quads will be saved through 2040 due to residential building energy codes.

The Alabama Energy and Residential Code (AERC) Board recently adopted the 2015 Alabama Residential Energy Code. While the residential code is based on the 2015 IECC, state-specific amendments weaken it significantly, making it more efficient than the 2009 IECC but not equivalent to the 2015 IECC. The updated residential code took effect October 1, 2016. Local jurisdictions may adopt more stringent codes, and several have adopted the 2015 IECC without the state-adopted amendments.

Last Reviewed: September 2019

Alaska does not have a mandatory statewide code for new residential construction. However, since January 2019, residential construction projects financed by the Alaska Housing Finance Corporation are required to meet the state-developed Building Energy Efficiency Standards (BEES), which is based on the 2018 IECC with state-specific amendments. Since the corporation finances approximately 20% of the market share, the majority of homes in Alaska are built to this standard. In addition, Alaska's Cold Climate Housing Research Center (CCHRC) found that about 68% of new residential construction adheres to BEES.

Last reviewed: September 2019

Arizona is a home-rule state, meaning that codes are adopted and enforced on a local rather than state level. However, the Southwest Energy Efficiency Project has found that the majority of new construction activity occurs in jurisdictions who have adopted the 2012 IECC or 2018 IECC.

Last Updated: September 2019

The Arkansas Energy Code for New Building Construction is mandatory state-wide for both residential and commercial buildings. The residential energy code is based on the 2009 IECC with amendments. This code became effective on January 1, 2015.  

Last Reviewed: September 2019

 

The 2016 Building Energy Efficiency Standards were adopted in June 2015, effective January 1, 2017 In June 2017 the California Energy Commission certified to U.S. DOE that the 2016 Standards exceed IECC 2015 by 29% on average for the residential building types analyzed (see Energy Commission Residential Energy Efficiency Comparison).  The 2016 Reach Standards, published in the California Green Building Standards (CALGreen), were adopted in October 2015, effective January 1, 2017, and establish standards for Energy Design Ratings that are 15% (Tier I) and 30% (Tier II) beyond the mandatory standards, as well as a Zero Net Energy Design designation, which local governments consider for adoption as local ordinances.

In May 2018, the CEC adopted the 2019 Building Energy Efficiency Standards, which take effect on Jan. 1, 2020, and are the first in the nation to require solar. The codes focus on four key areas: smart residential photovoltaic systems, updated thermal envelope standards, residential and nonresidential ventilation requirements, and nonresidential lighting requirements. Compared to the 2016 Standards, the 2019 Standards save 79% of electricity, 17% of demand, and 9% of natural gas for single-family buildings, and 53% on an energy cost basis.

Last Updated: July 2019

The 2003 IECC is a mandatory minimum for jurisdictions that have adopted a code previously. Jurisdictions that have not adopted or enforced codes are exempt from the 2003 IECC requirement, although the 2012 IECC is mandatory for all factory-built and multi-family structures – commercial and residential – in areas that do not adopt or enforce buildings codes. The State of Colorado Division of Fire Prevention and Control regulates the construction of health care and school facilities, and the 2015 IECC is mandatory for these specific construction types as well.

In the 2019 House Bill 19-1260 on Building Energy Codes was signed. The bill requires local jurisdictions to adopt one of the three most recent versions of the International Energy Conservation Code at a minimum, upon updating any other building code, and encourages local jurisdictions to update the Colorado Energy Office on any changes to the jurisdictions' building and energy codes.

As of June 2019, 76% of Colorado's population is on the 2012, 2015 or 2018 IECC.

Last Reviewed: September 2019

Following a review that began in January 2017 by the state's Codes and Standards Committee and Department of Administrative Services, state regulators voted in July 2018 to move forward with adoption of the 2018 Connecticut State Building and Fire Safety Codes, which include the 2015 IECC  for residential and commercial construction. The Connecticut Department of Administrative Service adopted the 2015 IECC effective October 1, 2018.

Details regarding the state's code adoption process and schedule can be found on its Code Adoption Webpage. In addition, Connecticut Law now provides the State Building Inspector and Code Committee a process to adopt and implement the latest IECC during the same year.  

Last Updated: July 2019

Residential construction in Delaware must comply with a weakened version of the 2012 IECC. The state began reviewing the 2015 and 2018 IECC in 2018. Residential and commercial codes are reviewed triennially by the Delaware Energy Office within the Department of Natural Resources and Environmental Control.

Last Updated: September 2019

Washington DC's energy codes are mandatory across the District. For residential buildings, builders must comply with the 2013 DC Energy Conservation code, which is roughly equivalent to the 2012 IECC.  The District also has a Green Construction Code that enhances energy efficiency requirements in addition to the energy code.  It applies to all commercial construction projects 10,000 square feet and larger and all residential projects that are 10,000 square feet and larger and four stories or higher.

Last Reviewed: September 2019

Effective December 31, 2017, Florida law requires that residential buildings comply with the 6th Edition (2017) Florida Building Code, Energy Conservation. The 6th Edition (2017) Florida Building Code, Energy Conservation consists of the foundation code 2015 IECC and amendments. (See https://codes.iccsafe.org/public/collections/FL). The Florida Building Commission certified in letters to the U.S. Department of Energy that the new code meets or exceeds 2015 IECC standards. Compliance with the code is mandatory for all new construction including alteration to existing buildings.

Last Reviewed: September 2019

 

On January 1, 2011, the 2011 Georgia State Minimum Standard Energy Code became effective statewide as approved by the Georgia Department of Community Affairs on November 3, 2010. The state code is based on the 2009 IECC with 2011 Georgia Amendments and is mandatory statewide.

Last Reviewed: September 2019

In July 2015, the Hawaii State Building Code Council adopted the 2015 IECC with state-specific amendments. The new codes took effect on July 1, 2015. However, until each county adopts the 2015 IECC, the counties of Hawaii, Maui, and Honolulu enforce the 2006 IECC; Kauai, the 2009 IECC. 

Last Reviewed: September 2019

The State of Idaho adopted the 2012 IRC with amendments that place it at 2009 standards. Idaho has adopted 2012 IECC residential provisions with amendments to 2009 standards for residential code, which took effect as of January 1, 2018. There are a few jurisdictions that adopted the 2015 suite of codes in 2017, including: Boise, Rathdrum, Idaho Falls, Ammon, Sun Valley, Rupert, Kuna, Sandpoint, Bannock County, Blaine County, Minidoka County, and Bear Lake County. Heyburn adopted the 2015 IRC codes only. The Idaho Building Code Board is currently reviewing the 2018 IECC codes. They plan to vote on amendments and a recommendation to present to the legislature when it convenes in 2020.

Last Reviewed: September 2019

By law Illinois is required to adopt the latest IECC, although the Capital Development Board may recommend amendments. Current code, effective July 2019, requires residential construction to meet 2018 IECC standards with state-specific amendments. 

Last reviewed: July 2019

The Indiana Energy Conservation Code is state-developed and mandatory statewide. For residential buildings, the 2011 amendments update the 2005 Indiana Residential Code to reference Chapter 11 of the 2009 IRC, with the amendments meeting the stringency of Chapter 4 of the 2009 IECC, effective as of April 5, 2012.

Last Reviewed: September 2019

The Iowa State Energy code is mandatory statewide for residential buildings, although jurisdictions are free to adopt stricter codes. As of March 2014, residential buildings must comply with the 2012 IECC, with state-specific amendments. 

Last Reviewed: September 2019

Kansas is a home-rule state and thus has no statewide residential building code, though realtors and homebuilders are required to fill out an energy-efficiency disclosure form and provide it to potential buyers. Many jurisdictions have adopted the 2009 or 2012 IECC. Based on information obtained in a 2013 survey of local jurisdictions and 2011 U.S. Census permit data, it is estimated the almost 60% of residential construction in Kansas is covered by the 2009 and 2012 iterations of the IECC. 

Last Reviewed: September 2019

As of October 1, 2014, the 2013 Kentucky Residential Code (KRC) mandates residential buildings must comply with the 2009 IECC or IRC with state amendments.

Last Reviewed: September 2019

Residential buildings must meet the 2009 IRC with reference to the 2009 IECC. Multifamily residential construction three stories or less must comply with the 2012 IRC and the energy provisions of the 2009 IECC. Multifamily residential construction over three stories must comply with ASHRAE 90.1-2007.

Last Reviewed: September 2019

The Maine Uniform Building and Energy Code (MUBEC) was established legislatively in April 2008 through P.L. 699, setting the 2009 IECC and ASHRAE 90.1-2007 as the mandatory for residential buildings statewide, effective June 1, 2010 with a six-month transition period. In 2011, P.L. 408 changed mandatory enforcement requirements for the Maine Uniform Building and Energy Code (MUBEC) to municipalities with populations over 4,000 starting December 1, 2010 for municipalities that had existing building codes and December 1, 2012 for municipalities that did not have existing building codes. For municipalities with a population less than 4,000 enforcement of the statewide code is voluntary. This change means that 89 of Maine’s 533 municipalities (based on 2010 census data) are required to provide enforcement of energy codes, representing 60% of the state’s residential population. The Technical Codes and Standards Board is currently working on the adoption of the 2015 IRC, IEBC, and IECC.

Last Reviewed: September 2019

Effective March 25, 2019, the 2018 Maryland Building Performance Standards are mandatory statewide and reference the 2018 ICC Codes, including the 2018 IECC, for all new and renovated residential buildings. § 12-503 of the Maryland Code requires the Department of Housing and Community Development to adopt the most recent version of the IECC within eighteen (18) months after it is issued and may adopt energy conservation requirements that are more stringent than the codes, but may not adopt energy conservation requirements that are less stringent. Each locality in the state must adopt and begin enforcement of the code within 12 months of state adoption.

Last Updated: July 2019

The Board of Building Regulations and Standards (BBRS) has adopted the IECC 2018 with MA amendments as part of the 9th edition of the MA state building code. The updated code will go into effect on January 1, 2020, and the energy chapters reference the IECC 2018 and ASHRAE 90.1-2016, with strengthening amendments. Strengthening amendments include a new section R407. The Board did not make significant changes to the residential stretch energy code, which continues to require HERS 55 or less for new construction with incentives for solar PV and onsite renewable energy or cold-climate heat pumps. Alternative residential stretch code options include meeting the Energy Star Homes 3.1 standard or the Passive House Standard.

Last reviewed: July 2019 

The 2015 Michigan Residential Code went into effect in February 2016 and is based on the 2015 IECC with Michigan-specific weakening amendments.

Last Reviewed: September 2019

Minnesota's residential building code is mandatory statewide. The IECC 2012 was adopted in August 2014 and went into effect February 2015.

Last Updated: July 2019

Mississippi's residential code is voluntary and is based on ASHRAE 90 – 1975 and the prior 92 MEC. Based on a June 2011 Energy Codes Economic Analysis conducted by BCAP and Southface, as well as additional data collected by MDA, approximately 60% (1.75 million out of a total 2.9 million residents) of the State’s population reside in cities or counties with building codes equivalent to 2003 IBC or higher, and the average code standard for these local jurisdictions is 2006 ICC. Jurisdictions can adopt more stringent codes, and several localities have done so for the residential code: Gulfport, Biloxi, Horn Lake, Ridgeland, Jackson, Greenville, Oliva Branch, Pascagoula, and Moss Point.

Last Reviewed: September 2019

Missouri is a home-rule state and thus has no mandatory state-wide codes. State-owned residential buildings must comply with latest edition of the MEC or the ASHRAE 90.2-1993 (single-family and multifamily buildings). Missouri maintains a database of building code adoptions in local jurisdictions. Approximately 50% of the state’s population is covered by the 2009, 2012, or 2015 IECC or equivalent codes.

Last Reviewed: September 2019

Montana's residential building code, codified in ARM Title 24, Chapter 301.160, is mandatory statewide. Montana's residential code requires compliance with the 2012 IECC, with amendments.

Last Reviewed: September 2019

Nebraska is a home-rule state, but its residential energy code, referred to as the Nebraska Energy Code (NEC), is mandatory statewide. Residential buildings are required to comply with the 2009 IECC with administrative amendments. Local jurisdictions can adopt any code that is more stringent than the NEC, and two municipalities have adopted the 2012 IECC: Gretna and Fremont. Nonetheless, 100% of new homes fall under the 2009 IECC as the NEC is the minimum standard. The Energy Office has conducted a study on the impact of the 2015 IECC. 

Effective July 1, 2020, the Nebraska Energy Code will be based on the 2018 IECC with no amendments. 

Last Updated: September 2019

On July 1, 2018, the 2018 IECC became mandatory for residential buildings. While the code is not being enforced statewide, a significant number of local governments are in the process of adopting it. Local governments are not allowed to adopt less-efficient energy codes.

Last updated: September 2019

Effective April 1, 2010, the New Hampshire State Building Code for residential buildings is based on the 2009 IECC, with state-specific amendments. The code is mandatory statewide. The NH Building Code Review Board is currently reviewing the 2015 IECC.

Although New Hampshire is not a home rule state, statutes allow municipalities to adopt amendments and codes provided they exceed the State Building Code. The town of Durham has adopted the 2015 IECC energy code (strengthened).

Last Reviewed: September 2019

Compliance with the energy provisions of the New Jersey Uniform Construction Code (UCC) for residential is mandatory statewide as of September 21, 2015, with a six-month grace period for the previously adopted codes to be used to not disrupt projects currently in design-stage. Residential construction must comply as mentioned above. The code includes a modification to Section N1102.4.1/R402.4.1 (Building thermal envelope) of the IRC and IECC which allows for either a visual inspection with checklist or [blower door] testing for compliance with the air barrier and insulation aspects of the building thermal envelope requirements. If testing is used, the 2015 criteria of 3 air changes per hour is the criteria to meet. 

For existing buildings, the Rehabilitation subcode (NJAC 5:23-6) applies certain energy conservation provisions of the new codes based on the scope of the project.

Last reviewed: July 2019

The 2009 New Mexico Energy Conservation Code (NMECC) is based on the 2009 IECC with state-specific amendments for residential building codes. All areas of the state are covered by local building jurisdictions and must meet or exceed the state minimum code. Because localities are permitted to adopt stretch codes, the City of Santa Fe and Town of Taos have adopted more stringent building codes. Builders can also use the NM 2009 Energy Conservation Code Residential Applications Manual to comply when building a passive solar or high mass home. The New Mexico Home Builders association is considering a request to update the residential code to IECC 2015.

Last Reviewed: September 2019

On March 9, 2016, the Fire Prevention and Building Code Council voted to adopt major updates to the New York State Energy Conservation Construction Code, incorporating the 2015 International Energy Conservation Code, ASHRAE 90.1-2013 and 2016 Energy Code Supplement. Effective October 2016, residential buildings must comply with the 2015 IECC. 

The State Fire Prevention and Building Code Council is empowered to adopt higher or more restrictive standards upon the recommendation of local governments. New York State began developing a stretch energy code with contributions from an advisory group and technical working groups represented by state and local government, utilities, design professionals, building trades and advocacy groups.  Named NYStretch-Energy, this state stretch code will be marketed statewide for optional local adoption in the second quarter of 2017.

NYSERDA is supporting NYSDOS in its rulemaking proceedings for state adoption of the 2018 International Energy Conservation Code. If passed, these national model codes would take effect on January 1, 2020.

Last Updated: July 2019

Effective January 1, 2019, the 2018 North Carolina Energy Conservation Code (NCECC) is mandatory statewide for residential buildings. The residential code is based on the 2015 IECC with amendments. 

Last Updated: September 2019

 

North Dakota is a home rule state and has no statewide mandatory energy codes. The state recently adopted an amended version of the 2015 IECC as its voluntary residential code. Approximately 83% of the state’s population lives in a jurisdiction that has adopted the ND State Building Code which includes the 2009 IECC.

Last Reviewed: September 2019

Effective July 1, 2019, a new residential code will be in effect based upon the 2018 IRC/IECC with amendments. Previously residential home builders were required to comply with the 2009 IECC.

Last Updated: May 2019

Oklahoma has in place mandatory statewide building codes for residential and commercial buildings buildings. The Oklahoma Uniform Building Code Commission (OUBCC) reviews and recommends building codes for residential and commercial construction. Residential buildings must comply with the 2015 IRC, however, the energy chapter references the 2009 IRC.

Last Reviewed: September 2019

The 2014 Oregon Energy Efficiency Specialty Code is mandatory statewide. Its provisions are developed by the state and are not based on a model code. The state currently enforces the 2014 Oregon Residential Specialty Code (ORSC), which has been certified to US DOE as equivalent/more efficient to IECC 2015. Oregon has approved IECC 2015 as an alternative and is putting in place provisions for it to replace the current Reach Code. Reach Code compliance is mandatory for all new state-owned and occupied buildings and substantial remodels. Oregon adopted a new Residential Code in 2017 (2017 Oregon Residential Specialty Code, or 2017 ORSC), which became effective October 1, 2017, with a 90-day phase-in period. The 2017 ORSC is based on the 2015 IECC with Oregon amendments, which include mandatory alternative efficiency package pathways for envelope efficiency and equipment such as furnaces, water heaters, and heat pumps that exceed federal minimums.

Last Updated: July 2019

In May 2018 Pennsylvania adopted of the 2015 IECC (some with amendments) effective October 1, 2018.

Last reviewed: July 2019

On July 1, 2013, Rhode Island formally adopted the 2012 IECC for residential buildings, with state-specific amendments. The code went into effect on October 1, 2013 and is mandatory statewide. While Rhode Island is a home rule state, towns are not permitted to adopt a code that is different from the state's. The code contains several amendments that diverge from the ICC published version of the 2012 IECC. The residential code utilizes the 2009 IECC insulation tables, which is not as rigorous as the 2012 IECC.  Rhode Island requires performance testing but does not require that the air exchange rate meet code. While there is no current stretch code, as part of the Rhode Island’s Energy Efficiency Procurement Plan, a Building Codes & Standards Initiative has been approved by the RI Public Utilities Commission, and a stated feature is the development of a “stretch” code targeting “15% more energy than buildings constructed according to the prevailing path.” This effort is being pursued in conjunction with the RI Building Code Commission and the RI Builder’s Association.

Issued in December, 2015, Executive Order 15-17 directs the Office of Energy Resources to coordinate with the Energy Efficiency and Resource Management Council, National Grid, and the Green Building Advisory Committee to establish a voluntary aspirational or stretch building code based on the International Green Construction Code or equivalent by 2017. Rhode Island now has a voluntary stretch code for residential buildings.

Last Updated: July 2019

On January 1, 2013, the 2013 South Carolina Energy Standard became effective. The residential provisions reference the 2009 IECC. Local jurisdictions may adopt more stringent energy codes.

Last Reviewed: September 2019

South Dakota has no mandatory statewide energy codes for residential construction. Codes are adopted by jurisdiction voluntarily. As of July 2011, state law established the 2009 IECC as a voluntary residential standard, however most jurisdictions have adopted codes based on the 2015 IECC. Local jurisdictions also have authority to adopt various residential building and energy codes, including IRC and IECC.

Last Reviewed: September 2019

 

State building codes adoption and enforcement efforts fall under the purview of the State Fire Marshal’s Office within the Department of Commerce and Insurance (C&I). Any changes to building energy code must comply with the state’s rule-making procedures. On November 2, 2015, C&I conducted a rulemaking hearing to adopt the 2009 IECC for residential one and two family dwellings and townhouses. The permanent rules were filed with the Secretary of State on November 4, 2016 and went into effect on February 2, 2017. See http://share.tn.gov/sos/rules/0780/0780-02/0780-02-23.20170202.pdf and https://www.energycodes.gov/adoption/states/tennessee for additional information.

However, because Tennessee is a “home rule” State, significant variation exists in codes adoption and enforcement at the local level. Under Tennessee statute, all local jurisdictions must adopt a residential energy code that is within seven years of the most recently published energy code. However, all local jurisdictions may also opt out of adoption with a two-thirds majority vote of the local governing body. In addition, local jurisdictions cannot be required to adopt a local code that is more stringent than the one adopted by the State, but they may voluntarily choose to adopt an updated code version. If opting out, the vote must be completed after each local election cycle. To date, 86 jurisdictions have opted in to the state residential building code (apply the statewide building code to their jurisdiction and utilize the state’s building permit system and building inspectors), 80 jurisdictions have opted out (building codes are not recognized nor enforced), and 264 jurisdictions are exempt (building codes are adopted locally, meeting or exceeding the statewide standard; exempt jurisdictions hire their own inspectors and all paperwork is administered locally and audited on a 3 year cycle).

The State began implementation and enforcement of adopted energy codes for new building projects in July 2011. The State Fire Marshal’s Office requires a State building permit for new residential and certain commercial construction in areas of the State, except those where an exempt local government is enforcing a residential or commercial building code itself or where the local government has notified the Department it has opted out of the law. Building construction projects subject to code enforcement by the State Fire Marshal’s Office are required to obtain a State building code permit prior to commencing construction. The Department verifies contractors' licensure as part of the permitting process.

According to C&I, a number of local jurisdictions have adopted building energy codes that exceed versions adopted by the State. TDEC OEP is aware of at least 109 local jurisdictions that have already adopted the 2012 Residential IECC, and 11 that have adopted the 2015 IECC.

Last Reviewed: September 2019

 

Texas' building codes are mandatory for residential construction. The Texas Building Energy Performance Standards requires single family homes to comply with the 2015 IRC and all other residential buildings to comply with the 2015 IECC. For all buildings, jurisdictions can choose to adopt more stringent standards. More than 50 jurisdictions, representing approximately 5.3 million people, have adopted codes more stringent than the minimum state requirements. 

Last Reviewed: September 2019

 

Utah’s Uniform Building Code (UUBC) for residential building energy codes is mandatory statewide. Residential building construction must comply with an amended version of the 2015 IECC.

In 2019, HB 218 further amended the residential codes. Existing weakening amendments adopted in 2016 with automatic increment improvements effective January 2019 include: 1.) A 5th compliance option, the Utah 2012 REScheck, which includes an equipment trade-off.  The required pass rate increased from 3% to 4%, January 1, 2019. 2.) Section R402 allows either blower door test or compliance to Table 402.4.1.1. The amended blower door requirement improved January 1, 2019 from 5 ACH to 3.5 ACH @50 pa for single family dwelling; however remains at 5 ACH @50 pa for townhouse/multi-family due to HB 218. 3.) Duct leakage testing is required with 25% of duct outside the thermal envelope. Allowed leakage dropped from 8 CFM/100 sq. ft. to 7 CFM/100 sq,ft. January 1, 2019. Amended ERI scores remain at 65 CZ-3, 69 CZ-5, 68 CZ-6. HB 218 included one amendment strengthening the whole house fan efficacies to the 2018 IECC level.

While localities may adopt stretch codes, it is a difficult process to do so. Localities may only adopt stretch codes if approved through the state legislative process. Amendments may not be adopted at the local level. As a result, none have adopted stretch codes.

Last Reviewed: September 2019

Vermont’s residential building energy code is mandatory statewide. Effective March 1, 2015, the RBES references the 2015 IECC with Vermont-specific amendments. The state is required by statute to update its codes every three years. 

Act 89 of 2013 gives the Vermont Public Service Department the authority to develop stretch codes and municipalities have the option of adopting them. The state's Residential Stretch Energy Code went into effect December 1, 2015. Any projects encompassed by Residential Act 250 are required to adopt the Residential Stretch Code. Thise code has a higher level of thermal energy efficiency than the Base CodeBoth Residential Base and Stretch Energy Codes also allow renewable energy to be used to meet the target Home Energy Rating Scores for compliance. Additionally, the Residential Stretch Code has Electric Vehicle charging requirements for multifamily developments of 10 units or more. 

Last Updated: July 2019

With an effective date of September 4, 2018, Virginia's Uniform State Building Code (USBC) has been updated to incorporate energy efficiency provisions for commercial buildings of the 2015 IECC and ASHRAE 90.1-2013.  All buildings with permit application date of September 4, 2019 or after must comply.  Residential buildings must meet requirements of the residential provisions of the 2015 IECC, with weakening amendments removing required envelope pressure (blower door) testing and improvements to attic/wall insulation R-values

Residential buildings had previously been required to comply with the 2012 IRC; however, a few technical amendments had rendered the code equivalent to the 2009 IECC.

Last reviewed: July 2019

The 2015 Washington State Energy Code is a state-developed code that is mandatory statewide. Based originally on the IECC it has been extensively modified to reach energy reduction targets.  Washington State is noted as the only state with energy code improvement requirements in statute. RCW 19.27a.160 (2009) “The council shall adopt state energy codes from 2013 through 2031 that incrementally move towards achieving the seventy percent reduction in annual net energy consumption”.

The state is on track to achieving these goals, having incorporated code changes achieving 35 percent reduction in whole building energy use compared to the 2006 edition. The residential and commercial codes include standards more stringent than the 2015 IECC and ASHRAE 90.1-2013. 

Last reviewed: July 2019

West Virginia's residential building code is mandatory statewide; however, adoption by jurisdictions is voluntary. The 2013 West Virginia Legislature passed a bill updating the state’s building energy code to follow the 2009 IECC for residential buildings. The new residential code became effective November 30, 2013.

Last Reviewed: September 2019

The state-developed residential code, referred to as Wisconsin Administrative Chapter SPS 322, Wisconsin Uniform Dwelling Code (UDC), is mandatory statewide for one- and two-family dwellings and incorporates the 2009 IECC with state amendments. These amendments are more restrictive for underfloor insulation for heated slabs. Local governments cannot modify the UDC and are required to enforce the UDC. 

Last Reviewed: September 2019

 

Wyoming's residential building code is voluntary. Known as the ICBO Uniform Building Code, it is based on the 1989 MEC and may be adopted and enforced by local jurisdictions. Some jurisdictions have adopted more stringent codes than the voluntary standard: the 8 most populated cities and counties in Wyoming have an energy code that meets or exceeds the IECC 2006 or equivalent. Teton County and Jackson are moving to the IECC 2012; Cheyenne adopted the IECC 2009; Casper, Rock Springs, and Gillette adopted a modified IECC 2006.

Last Reviewed: September 2019