A stretch code is an adoptable and enforceable code that provides adoption jurisdictions with a more stringent, uniform code option to achieve greater energy efficiency than the state's or municipality's base energy code. Stretch codes can support states in attaining more significant energy savings, emission reductions, and zero energy building goals. Stretch codes always address energy efficiency and may contain forward-thinking provisions pertaining to operational emissions, renewables, electrification, embodied carbon, and possibly include water efficiency or building material impacts. Stretch codes may be required for specific building types, building sizes, certain funding or incentive programs, or be voluntary.
Many times, a stretch code will be based on the next version of the model code; for example, a state may adopt the 2021 International Energy Conservation Code (IECC) as the base code and the 2024 IECC as the stretch code. A state or jurisdiction (i.e., OR, MA, VT) may also produce and adopt a state- or jurisdiction-specific stretch code. A stretch code is adopted and developed using the same public process as other energy codes and provides uniform criteria across a state or municipality.
Stretch codes range in savings from a certain percent better than the base code (i.e., 20 percent better than ASHRAE 90.1) to providing a pathway to zero energy ready or zero energy buildings. British Columbia, Canada, has adopted a "step" stretch code which is a stretch code with multiple levels of increasingly stringent compliance options. Stretch code compliance paths vary from prescriptive, performance, or points based.
Stretch codes accelerate the design and construction industry's acceptance of building methodologies, technologies, and materials that may be included in future versions of a model base energy code. By promulgating potential future code requirements in advance, the multifaceted construction market, product manufacturers, and distributors can align to meet approaching code developments. In addition, training and workforce development around emerging code provisions and construction practices, can help ensure higher code compliance in the future.
Overall, stretch codes benefit communities, home and building owners, and renters by:
- Reducing operational building and utility costs.
- Improving occupant comfort and health.
- Creating and sustaining efficiency-related jobs.
- Raising a building or home valuation.
- Strengthening the building and design industry and moving market trends toward efficiency.
State and Local Stretch Code Maps
The Building Energy Codes Program (BECP) tracks stretch codes at the state and local levels. The residential and commercial stretch code maps and corresponding tables visualize the current state of stretch codes in the United States. Navigate the maps below by selecting a state or local jurisdiction to learn what type of stretch code has been adopted and other information. The maps are updated on a quarterly basis.
The U.S. Department of Energy (DOE) and Pacific Northwest National Laboratory (PNNL) are developing a series of technical briefs supporting national, state, and local initiatives to update and advance building energy codes. These technical briefs are presented in a module-based format, based on technologies, measures or practices (or optimized combinations) that can be incorporated as “plug-ins” to building energy codes. These plug-ins are made available for adoption directly by state and local governments pursuing advanced energy savings and greenhouse gas (GHG) emissions reductions, as well as for future consideration for the International Energy Conservation Code (IECC) and Standard 90.1. The collection supports the adoption of stretch codes, helping state and local governments pursue their energy and climate goals, as well as the Department’s broader mission to provide technical assistance supporting the implementation of state and local energy codes (42 USC 6833).
Currently available plug-ins are presented below. Each tech brief provides an overview of a given topic, plus supporting technical information and analysis estimating the associated impacts. In addition, sample code language is provided to illustrate how a given concept can be overlaid on top of the current model codes (e.g., IECC or Standard 90.1). Additional technical assistance is available from DOE and PNNL to support states and local governments who are interested in adding these concepts or other “stretch” provisions to their building codes. Assistance typically includes technical guidance, customized analysis of expected impacts (e.g., based on state-specific building stock, climate considerations, or utility prices), and further tailored code language to overlay state building codes or other standards. DOE works continuously with states and local governments to identify new concepts and practices that support their needs and plans to issue additional plug-in concepts in the future on a rolling basis.
Technical Briefs
| Title | Description | Report Link | Fact Sheet Link |
|---|---|---|---|
| BPS and Energy Code Alignment | This technical brief presents recommendations for changes that may be incorporated into energy codes to facilitate future compliance with the building performance standard (BPS) policies that a newly constructed building has to meet once it is occupied. It provides background on the basis and benefits of the proposed changes and model code language that can be inserted into ASHRAE Standard 90.1 or adapted into other energy codes. | Code Alignment Tech Brief | |
| Zero Code Plug-In | This commercial zero code plug-in technical brief presents modified code language that can be amended to adopted commercial building model energy codes to achieve net zero operational energy emissions (NZOEE) or net zero energy (NZE) in newly constructed buildings, either immediately or over several code cycles. | Commercial Plug-In | |
| EV Charging |
Numerous studies show that sales of plug-in electric vehicles (PEVs) have grown consistently over the past 2 years in the U.S. Edison Electric Institute (EEI) estimates one million PEVs on the road in 2018 and forecasts a total of 18.7 million PEVs on the road by 2030. Based on this forecast, EEI projects the need for an additional 9.6 million PEV charging stations by 2030. States and local governments have expressed interest to DOE in having energy code overlay requirements to support policy goals. This technical brief provides code language for PEV charging infrastructure for adoption by model codes, and states and local governments. |
EV Tech Brief | EV Fact Sheet |
| Simplified HVAC System Performance |
The technical brief provides an additional heating, ventilation, and air conditioning (HVAC) System Performance (HSP) path that goes beyond the prescriptive energy code. It provides a comprehensive performance-based approach for HVAC system evaluation and analysis. The approach develops a Total System Performance Ratio (TSPR) to compare proposed, target, and reference HVAC systems. The technical support documentation (TSD) provides background on development of mechanical system performance factors for use in the HSP for ASHRAE Standard 90.1-2022. It provides documentation of HVAC system input parameters and simplified HVAC measure modeling approaches. |
|
HSP Fact Sheet |
| Energy Credits | This technical brief provides additional energy efficiency measures that go beyond the current prescriptive commercial energy codes. It demonstrates relative savings for multiple measures and shows a base savings package by building type and climate zone that is cost effective for building owners and tenants. | Energy Credits Tech Brief Energy Credits Application Guide: ASHRAE Standard 90.1-2022 |
Energy Credits Fact Sheet |
| Electric Readiness | This technical brief provides requirements for electric readiness that could be incorporated into model residential energy codes. It provides background on the basis and benefits of the provisions, and model code language that can be plugged into the IECC or adapted into other energy codes. | Electric Readiness Fact Sheet | |
| GEB (Demand Response) | This technical brief provides requirements for demand-responsive thermostats and water heaters that could be incorporated into model residential energy codes. It provides background on the benefits of these devices, impacts on the cost of construction, and model code language that can be plugged into the IECC or adapted into other energy codes. | GEB Tech Brief | GEB Fact Sheet |
Code Change Proposals Currently Being Considered
Below are draft code change proposals DOE is considering for stretch code and model code development.
| Title | Proposal Link |
|---|---|
| Clarify Slab Insulation Requirements | Proposal |
| Commercial PV Required | Proposal |
| Decorative Lighting Power Reduction | Proposal |
| Demand Control Ventilation Update | Proposal |
| EV Charging | Proposal |
| Expanded C406 Energy and Demand Response Credits | Proposal |
| Exterior Lighting | Proposal |
| HVAC Total System Performance Ratio | Proposal |
| Interior Lighting LPD Update | Proposal |
| Lighting System Performance | Proposal |
| Residential Demand Response | Proposal |
| Residential Electrification | Proposal |
| Residential PV Required | Proposal |
| Residential Renewable Tradeoffs for Performance Path | Proposal |
Other Resources
Building Energy Codes and Grid-Interactive Efficient Buildings
Filling the Efficiency Gap to Achieve Zero-Energy Buildings with Energy Codes
Realizing Demand Flexibility with Commercial Building Energy Codes
DOE Building Energy Codes Program
The U.S. Department of Energy supports the advancement of building energy codes, including stretch codes that empower states and local governments in achieving their energy and climate goals. Modern building codes and standards offer cost-effective solutions, contributing to lower utility bills for homes and businesses, and helping to mitigate the impacts of climate change.