IECC Compliance and Enforcement

Implementation of the Model Energy Code is foundational to achieving energy savings and reductions on GHG emissions across building stock, both residential and commercial. The first step is adoption of the most recent model energy code, followed by training and full implementation of the adopted code, and moving forward with periodic adoption and implementation of increasingly stringent codes.

According to the US Department of Energy, to date the model energy codes for residential and commercial buildings are projected to save (cumulative 2010-2040).

  • $126 billion energy cost savings
  • 841 MMT of avoided CO2 emissions
  • 82 quads of primary energy

These savings equate to the annual emissions of:

  • 177 million passenger vehicles
  • 245 coal power plants
  • 89 million homes

Getting Started

Although there is significant evidence of the value of energy code implementation, studies also show millions of dollars of untapped energy savings in states across the country.[i]

Assessing the current construction practices, establishing compliance and enforcement goals, and accessing intake plan review inspection tools are the first steps to successful compliance and enforcement.

The following information is provided to support jurisdictions in enforcement of the energy code.  Compliance tools are resources are found here.

Identify Current Construction Practices and Enforcement Practices

Assessing current practices can identify training needs and provide local evidence to the value of more comprehensive enforcement.

Quantitative Assessment

A quantitative assessment of the building stock provides a baseline of current construction practices. The assessment not only captures the value of untapped code compliance, but it will also provide a tool for measuring improvement.  Two significant and related methodologies have been established for providing quantitative assessments.  The current Building Energy Codes Program (BECP) Single-family Residential Field Study Protocol is appropriate for application for state or regional assessments or residential construction.

The methodology is based on key items identified as having the most significant direct impact on energy savings in single-family households. Efficiency measures are observed as installed in actual homes over a representative sample of households.  The resulting findings depict baseline construction trends and related energy-efficiency potential for a given state and help identify areas for further intervention, commonly through education and training initiatives.

The DOE’s commercial field study methodology is capable of determining, for a given sample of buildings, how much energy cost savings could potentially be gained through better compliance with the code. Stay up to date on reports and tools from the BECP by visiting their website.

The Institute for Market Transformation’s (IMT) City Energy Project has among their tools the Assessment Methodology for Commercial Building Code Compliance in Medium to Large Cities.  While it is based on the DOE methodology, it specifically provides a four-step process specifically for use within jurisdictions and includes both residential and commercial buildings. Such an assessment can be internally generated by the organization or the assessment can be completed by an outside contractor.

Evaluations will answer questions, such as:

  • What types of buildings are being built and renovated in my jurisdiction? What are the predominate ages and/or system types?
  • How well is the energy code currently implemented at construction?
  • What are the current processes in place to evaluate energy code compliance?
  • Who is evaluating energy code compliance at intake, permit, construction and prior to certificate of occupancy?
  • What areas of the energy code is the jurisdiction having trouble implementing? Which of those would have the most impact?
Qualitative Assessment

Building departments range in size from a single person doing all permit reviews and inspections to hundreds of employees, each specializing in one aspect of the construction or permitting process.    A qualitative assessment will help clarify staffing and workflow issues and help to identify issues that can be addressed to aid in improved compliance.  The IMT Methodology includes a process for identifying the issues within the jurisdiction that may be impacting energy code compliance.

Typically identified challenges include training and education, procedures and tools for plan review and inspection, and staffing. The following are suggestions on the steps to take with examples and best practices of implementation and compliance across the nation.

Set a Goal and Establish a Plan

An assessment of current energy code compliance will usually come with some recommendations for improvement.  These could be procedural by dedicating staff to certain activities, or code-measure recommendations suggested for implementation.  While it may be tempting for some jurisdictions to implement all the recommendations and achieve 90 percent or greater compliance with the energy code immediately, it is better to choose a select few but impactful code items to emphasize, and then move on to additional, more detailed energy code measures.

Examples of such initial goals could be:

  • By 2025, 90 percent of all HVAC systems will be right sized to ACCA Manual J and Manual S or ASHRAE 183, as applicable.
  • By 2022, request the commissioning report of all applicable projects prior to the certificate of occupancy.
  • By 2025, implement a sector-wide air-leakage verification program that collects all blower-door tests of applicable scopes of work prior to certificate of occupancy and establishes quality control on a random percentage of projects.

Plan Review and Inspection Tools

Compliance and enforcement tools are needed to implement the energy code. ICC has developed a no-cost simplified residential intake/plan review and inspection form based.  Written for the 2018 IECC, it is modifiable by the jurisdiction and can be adjusted to reflect local amendments and other code years.  PNNL and ASHRAE have developed a spreadsheet-based compliance form that meets the documentation requirements of Standards 90.1-2016 and 2019 Section 11 Energy Cost Budget Method and Appendix G Performance Rating Method, and a performance rating method reference manual.

ICC has developed a Model Program for E-Permitting, Plan Review and Remote Virtual Inspections that should be available in early 2021 in the bookstore.

Additional tools may be developing a priority checklist, phased implementation, or strategic use of third-party providers.

Develop a Priority Checklist

A priority checklist can help focus attention on implementing fewer items more thoroughly; perhaps listing the “top ten” highest-impact code requirements with which all projects must comply. Separate lists can be created for any specialized plan reviewers and inspectors, such as electrical and plumbing.  For residential compliance, the list should be based on the key items identified by the single-family residential field study as having the greatest direct impact on residential energy consumption. These key items are listed here:

  • Envelope tightness (ACH at 50 Pa)
  • Window U-factor
  • Window SHGC
  • Wall insulation (assembly U-factor)
  • Foundation insulation (floor/basement wall/slab)
  • Ceiling insulation (R-value)
  • Lighting (percent high efficacy)
  • Duct tightness (CFM per 100 square feet of conditioned floor area at 25 Pa).

Prioritizing commercial code provisions is not as simple as prioritizing for residential compliance, as the impact of measures will vary considerably across climate zones and between building occupancies.  Consider for a moment how differently a six-story hospital in south Florida uses energy compared to a warehouse in Minnesota, however the one commonality is the use of controls for efficient use of lighting and HVAC systems.

Phased Implementation

Proven effective by Chief Building Official Gil Rosmiller in the City of Parker, Colorado, phased or staged implementation can be very effective. It provides time for all stakeholders involved to learn new construction and enforcement practices.   It is important to communicate the plan to stakeholders and to provide education to code enforcement officers and building professionals for each phase. Findings from the AHJ assessment or prior knowledge of challenges will drive the plan. An example of a phased strategy based on local needs comes  from Castle Rock, Colorado demonstrates how this could work. The Castle Rock building department recognized two issues:  the need for education on heating and cooling equipment (duct and capacity sizing is probably the most complex to learn) and building enclosure requirements that must be enforced before accurate load calculations can be made. Their plan started with building enclosure requirements, followed by diagnostic testing and finally mechanical load sizing.

What is prioritized first depends entirely on the AHJ.  For example, upon recent energy code adoption in Saudi Arabia, the initial focus was on ceiling and roof insulation, and other international markets have indicated they would start with commercial lighting – the strategy is the same, and it is based on current construction practices, climate conditions and the needs of the AHJ.

Third-party Plan Review and Inspection

If lack of resources is resulting in lack of compliance, third party plan review may be a solution. The South-central partnership for Energy Efficiency as a Resource (SPEER) notes several benefits in their guidance on use of third parties[i]:

  • Enhanced city energy code inspection capability, reduced inspector workloads.
  • Less permitting time, more compliance.
  • Lower project costs, quicker turnarounds; accelerated local property tax enrollment.
  • Better quality control, more project oversight (city sets inspector criteria).
  • Increased market awareness of project developer.

Planning and oversight is required for effective use of third-party providers.  SPEER notes several of the keys to effective use include clearly defined qualifications, defined inspection documentation requirements and that conflict of interest be included in the selection process.  Use of a third party can only be implemented if the city code includes procedures for authorizing third parties. The SPEER best practice guidance can be found in ICC’s building energy model policy and resources database.

[i] Texas City Efficiency Leadership Council Best Practice, Third-Party Energy Code Inspection. SPEER, SECO, HARC

[i] Jeremy Williams, Presentation at the 2019 National Energy Codes Conference, July 2019

Addressing Common Technical Challenges

Based on a recent nationwide analysis of frequently asked questions, 35 percent of the queries were focused on residential compliance and the remaining 65 percent focused on commercial.

Residential code questions focused on topics that have generally long been associated with building energy efficiency. The queries included both mandatory (applicable to all compliance paths) and prescriptive items: air leakage and barriers, ducts, envelope insulation and mechanical ventilation. As shown below, there are extensive resources available to address these issues.

Commercial code questions emphasized mechanical systems and controls, lighting controls, roof insulation and additional efficiency packages.  There is not the same wealth of resources for commercial provisions as residential, due in part to the complexity of issues, and lack of analysis.   However, the DOE commercial field study provides insight into the measures that provide the greatest untapped energy savings—controls and commissioning, and fenestration efficiencies

Residential Air Leakage

Limiting air leakage (2012, 2015 and 2018 IECC Section R402.4) is a non-tradable energy code requirement and applies to residential projects regardless of the compliance path selected by the builder. Air leakage requirements include air barrier criteria and testing. Noncompliance with these requirements impacts the energy use of all residential projects.

Air leakage in the building envelope is generally referred to as infiltration, even though it is infiltration and exfiltration. Differentials in pressure and temperature cause air movement through the building thermal envelope if it is not properly sealed. This allows conditioned air to escape and can create particularly inefficient building energy use. Infiltration and exfiltration occur at the same time while the building works to balance itself, with air finding cracks and holes in the air barrier.

The impacts are significant, air leakage can account for 25 to 40 percent of energy used for heating and cooling in a typical residence.

Solutions:  Air leakage and air barrier guidance are well-researched and well-documented energy code provisions. Resources covering the energy and durability impact of air leakage, air testing procedures, air barrier materials, air sealing and other air leakage topics are plentiful. Guidance on air leakage testing in existing buildings is also well documented. Trained and certified air barrier contractors can be found on the Building Performance Institute website ( and Air Barrier Association of America website (

The resource database includes comprehensive resources including those focused on Air Leakage Testing,  Air Barrier and Sealing Materials  and Air Leakage in Existing Resources.

Residential Duct and Duct Testing Requirements

Duct sealing and testing are non-tradable requirements, and the minimum provisions must be met regardless of the path selected for compliance. (2012 and 2015 IECC Section R403.2.2, 2018 IECC Section R403.3) In the 2015 and 2018 IECC, the values of duct leakage are prescriptive, as is the duct insulation.  Ducted systems must transfer fresh or conditioned air from the air-handling unit to rooms around the building. IECC provisions specific to ducts and air handlers improve energy efficiency in the design and installation of these systems.

The effectiveness of the ductwork is critical to efficient energy use in the building and providing comfort to occupants. Many HVAC energy experts estimate that about 20 percent of conditioned air intended for distribution in the dwelling unit does not make it to the room or space because of leaks, holes and poorly constructed ductwork systems. Translating this into untapped energy savings shows that nearly 40 percent of the homes in DOE field studies did not meet duct leakage requirements which represented an average statewide annual savings potential of 44,500 MMBtu ($832,400).

Duct sealing is critical regardless of duct location.  However, the value of duct insulation is more dependent on duct location. Ducts traditionally have been in unconditioned spaces such as attics, crawl spaces, garages or unfinished basements, due to extreme winter and summer temperatures in these spaces, 10 to 30 percent of the energy used to heat and cool the air is lost through the duct surfaces.

ANSI/RESNET/ICC 380-2016: Standard for Testing Airtightness of Building Enclosures, Airtightness of Heating and Cooling Air Distribution Systems, and Airflow of Mechanical Ventilation Systems provides a standard for testing the integrity of duct systems and air distribution systems.  Additional resources on efficient duct design, insulation and testing can be found in the ICC building energy resource database.

Residential Building Envelope Insulation Requirements

Insulation requirements for the building thermal envelope, including ceilings, roofs, walls, floors and foundations, are tradable depending on the compliance path selected for the project (2012, 2015 and 2018 IECC Sections R402.1and R402.2). Noncompliance with building envelope insulation requirements has a significant impact on the energy use.

Building envelope insulation directly impacts building energy use by reducing the heating and cooling loads of the building, with a high awareness factor. Despite this, insulation questions represented one of the top four categories in nationwide frequently asked questions (FAQs) and nearly 60 percent of the field study homes did not meet prescriptive insulative requirements, representing an average statewide annual savings potential of 67,900 MMBtu ($1,205,000). Additionally, the reduction in loads can reduce the required sizes of the heating and cooling equipment, thereby providing secondary cost savings.

Solutions:  Resources abound on insulation installation.  However, transference of these resources is needed; installers, project superintendents and code officials all require training.  General and climate zone specific resources can be found in the building energy resource database, and training is provided by the High Performance Insulation Professionals, among others.

Commercial Controls

The  inclusion of HVAC and lighting controls has increased considerably in the last several code cycles, and according to  PNNL analysis better compliance offers 12 percent savings in total building energy cost.  The 14 most impactful HVAC and lighting control measures include:

  • controls for thermostat deadband,
  • economizer,
  • variable air volume box minimum,
  • off hour temperature setback,
  • outdoor air dampers; (6) supply air temperature reset,
  • zone isolation,
  • demand-controlled ventilation,
  • fan static pressure reset,
  • optimum start,
  • occupancy sensors,
  • daylighting,
  • exterior lighting controls, and
  • lighting time switches.

The potential recovered lost energy cost savings through better compliance with the 14 impactful control measures is substantial at $168 –per thousand square feet per year.  The measures are in current code, but compliance varies - approximately 12 percent of total building energy cost could be saved through better compliance with these measures.

Solution:  The best way to ensure controls are installed, calibrated and set properly is through commissioning.  The 2018 and 2021 IECC include functional testing and commissioning requirements in Section C408. Guidance on commissioning is found in the ASHRAE Guideline 0 - The Commissioning Process and  ASHRAE/IES Standard 202, Commissioning Process for Buildings and Systems.  and .  As described by ASHRAE, “The Commissioning Process is a quality-focused process for enhancing the delivery of a project by achieving, validating, and documenting the performance of facility elements in meeting the owner’s objectives and criteria. Guideline 0 provides a template for Cx Plans for specific facility elements or assemblies and establishes common content that serves as a uniform method for achieving different levels of commissioning and meeting varying owner's requirements. The guideline serves as the foundation for authoring technical commissioning guidelines more narrowly targeted and focused on specific applications.”

[1] Data is not available to determine what percentage of the units may have used the performance or ERI compliance path and traded the insulation levels against other efficiencies.

Provide Training and Education

Training and education can be impactful, and several models are available including focused issue-based training, site education, circuit riders and more traditional broad-based code training.  The most effective training provides audience-specific delivery targeted to its needs; technical assistance to key stakeholders; and circuit rider programs to ensure that the building, design and enforcement industry has the required resources to design, build and enforce energy codes.

Issue Based Training

Issue-based training has been proven effective in supporting code enforcement and compliance. Across seven states DOE demonstrated issue-based training worked in nearly all scenario - focused on the specific compliance issues facing the state.

The value of training on changes in building practices ranged from annual statewide savings of 1.2 to 4.8 million dollars.  It is important to note these changes were based on compliance with the code adopted in that state, ranging from the 2009 IECC to the 2015 IECC.

This success was based on several training strategies ranging from traditional classroom stand up training to online and on-site training. The states developed partnerships with broad groups of stakeholders to deliver the training that included:

  • Curriculum partnership with community college
  • Circuit riders
  • Tablets and apps in partnership with home energy raters
  • Multimedia messaging combined with on-site training
  • Blend of industry marketing and outreach, and training events.

The successful training was based on several strategies ranging from traditional classroom stand up training to online and on-site training.

  • Curriculum partnership with community college
  • Circuit riders
  • Tablets and apps in partnership with home energy raters
  • Multimedia messaging combined with on-site training
  • Blend of industry marketing and outreach, and training events.

Circuit Riders

Circuit rider programs have been effective in supporting energy code compliance in states as diverse as Idaho, Massachusetts, Kentucky, Florida and Texas. Unlike traditional, broad based one-size fits all training, circuit riders provide topical training and education to stakeholders where and when they need it. They generally travel the state visiting jurisdictions and project sites, providing clarification and support for implementation of the energy code.  Part of the success is the peer-to-peer focus and relational support. Circuit riders also generally reach more stakeholders, resulting in broader application of the training because the circuit rider spends time in the jurisdiction where more stakeholders have access to them, and specific issues are addressed. The Florida circuit rider program focused primarily on commercial construction and site visits across the state. Some highlights were:

  • Introductory communication between Circuit Rider and building department about the site visit and its goals.
  • Pre-visit questionnaire regarding the building department’s processes.
  • Full day meeting on-site (a half day with plans examiners and a half day with inspectors).

The Idaho Energy Code Circuit Rider program is funded by the Northwest Energy Efficiency Alliance.  In Idaho, the circuit rider provides free assistance to jurisdictions, permitting departments, code officials, and design and construction professionals through:

  • Technical support via email and telephone
  • On-site education, training and technical assistance for Idaho code jurisdictions and other industry professionals
  • Code interpretations, and installation and enforcement techniques.


Visit the International Code Council energy resources page for more information.