Energy Conservation Code

As of Dec. 1, 2024, all projects must be designed to meet the 2018 ICC suite of codes and the 2024 City of Boulder Energy Conservation Code.

• City of Boulder 2024 Energy Conservation Code

• 2024 Energy Conservation Code FAQs
  • *Errata can be found on at the bottom of the FAQ webpage.

Projects that fall under the 2020 City of Boulder Energy Conversation Code can find information on the 2020 code at the bottom of this page.

• 2020 CoBECC Worksheets, Guides and Resources

The city hosted two virtual trianings on Residential and Commercial updates to the code. You can watch below.

• Watch the Residential Updates training

• Watch the Commercial Updated training

The overall long-term goal for the city’s energy code is to build high performance, net zero energy (NZE) residential and commercial buildings. The objectives below are designed to support this overarching goal.

Supporting the City’s Climate Commitment

• To achieve and sustain significant greenhouse gas (GHG) reductions (80% reduction by 2050)
• To design and adopt NZE, outcome verified codes for all building types by 2031
• To support technologies and practices that will move the community toward local, distributed and renewable energy systems (for both buildings and transportation) that support the goal of 100% renewable electricity, economic vitality and community resilience

Promoting High Performance Buildings

• To promote sustainable building practices throughout the lifecycle of the building process (e.g., waste management, water management, transportation impacts, etc.)
• To promote the development and ongoing maintenance of safe, comfortable and high-performing buildings
• To support energy resilience (i.e., the ability to maintain operations during grid failure)

Creating Effective and Viable Codes

• To adopt codes that are feasible (e.g., updated regularly, implementable, and enforceable)
• To provide building owners and design professionals with viable and economically feasible paths to comply with energy codes that are straightforward and easy to understand

What is Net Zero Energy (NZE)?

While NZE can be defined several ways, in this context, NZE means:

The amount of renewable energy produced on site, plus the amount purchased from approved community energy systems, is equal to or greater than the annual energy consumption of the site.

This definition makes it possible for all buildings to become NZE even with poor solar access or other site constraints. Current conversations among experts and advocates at the national level have introduced alternative terminology, including terms such as “net zero carbon’ codes and ‘net zero emissions’ codes. Staff is engaged in these conversations and may propose updated terminology in future updates.

While the majority of this is addressed within the energy code itself, some key components such as waste, water, and transportation impacts are covered in applicable sections of the International Building Code (IBC) or International Residential Code (IRC).

Similar Energy Rating Index (ERI) requirements as 2020 Code but with new parameters

An ERI score is similar to a Home Energy Rating System (HERS) score. This is a numerical score where 100 equates to the efficiency levels prescribed in the 2006 International Energy Conservation Code and 0 is equivalent to a net-zero-energy home. In the 2024 code, new construction and additions over 1,000 square-feet and major alteration projects must demonstrate compliance with Boulder’s energy code by using the prescribed ERI compliance path. In the 2024 code for new construction, an ERI score of 0 is still required for homes 3,000 square-feet and larger but homes less than this will now need to achieve an ERI of 30 or less. This is illustrated in the chart below.

Envelope Backstop

Under the new 2024 energy code new construction, additions and major alterations now are required to be all electric and cannot utilize fossil fuel type energy source. This means all space and water heating, cooking, fireplaces, outdoor pool and spa heaters will need to be electric or rely on another non-fossil fuel.

All-Electric Requirements

Similar to requirements that already exist for Boulder County projects, all residential pools, spas, outdoor radiant heating, and snow melt systems will be required to offset 100% of the system’s annual energy use by on-site renewable energy generation.

Code Provisions for Alterations

The 2020 code required additional energy efficiency improvements be made when renovating homes based on the construction value of the project. The 2024 code continued to require energy efficiency improvements for home renovations; however, the levels of alteration have been updated and you will notice there is no longer a level 4 alteration. This was done to alleviate confusion and help streamline the process and allow better alignment with the International Existing Building Code.

Commercial Energy Use Index (EUI) Performance Path

The 2024 code continued the EUI target compliance path that allows Boulder to transition towards NZE and net-zero emissions. The 2024 code has been updated to utilize a site energy approach instead of a cost-based approach like the previous code.

Solar Mandate

To meet long-term NZE performance goals, it was necessary to encourage the deployment of renewable energy at the project level. The 2020 code mandated solar-ready requirements of at least 5% of commercial building energy use be supplied by on-site renewables for new construction. Under the 2024 code, only projects pursuing the modeled baseline pathway (C407.3.1) would still need to meet this 5%; projects pursuing the fixed performance target pathway (C407.3.2) no longer has this limitation.

Measured Performance Outcome-Verified Code Path

The 2020 code provided an outcome-verified code compliance path. The 2024 code still allows this path for any projects that would like to pursue it. The goal for this compliance path is to utilize actual metered energy use to show compliance instead of design-based values only.

Electric Vehicle (EV) Charging Requirements

In 2020, provisions required commercial and residential projects provide EV charging infrastructure. Because technology has evolved and the demand for EV charging is better understood, the 2024 code clarified and adjusted these requirements for commercial projects to better align with the state requirement. .

Alteration Levels

• Level 1 Alteration

  • Alteration with scope that includes the removal and replacement or the covering of existing materials, elements, equipment, or fixtures using new material, elements, equipment or fixtures that serve the same purpose.

• Level 2 Alteration

  • Alteration with scope that includes the reconfiguration of space, the addition or elimination of any door or window, the reconfiguration or extension of any system, or the installation of any additional equipment.

• Level 3 Alteration

  • Alteration where the work exceeds 50% of the building area. If mechanical or water heating is altered part of the alteration, then the equipment space must be made electric ready for future electric equipment to be installed.

• Level 3+ Substantial Alteration

  • Alteration that modifies 50% or more of the floor area AND includes replacement of major mechanical systems AND substantial thermal envelope modifications must install electric equipment as the primary source of space and water heating. Gas appliances would still be allowed for backup space and water heating or small loads, such as cooking and drying; Substantial is defined as 50% or more. New residential construction projects, ADUs and additions (less than or equal to) ≤ 1,000 square-feet shall comply with the residential energy prescriptive or performance requirements in the CoBECC. Projects (greater than or equal to) ≥ 500 square-feet shall comply with the performance requirements and are required to achieve the applicable ERI. The ERI is the non-trademark equivalent like a HERS score and provides an energy efficiency requirement for your residential construction project. New residential construction is moving toward Net Zero Energy, with all buildings being required to meet that standard by 2031.

Search for local certified RESENT home energy raters that can calculate your project's ERI.

The 2024 energy code no longer specifies mandatory measures in the prescriptive code. They now can be found in table R406.1.1 for when the performance pathway is pursued. If the project is pursuing prescriptive compliance, all provisions under R401-R404, R407 and R408 must be met unless not applicable.

A new section has been added to the code for Additional Conservation Measures. This section helps align with the state required energy code minimum and introduces some new options as we look ahead at not just energy use reduction but overall emissions reductions. These sections have many energy efficiency credits as well as embodied carbon options to help show compliance.

Alteration Levels

• Level 1 Alteration

  • Alteration with scope that includes the removal and replacement or the covering of existing materials, elements, equipment or fixtures using new material, elements, equipment or fixtures that serve the same purpose.

• Level 2 Alteration

  • Alteration with scope that includes the reconfiguration of space, the addition or elimination of any door or window, the reconfiguration or extension of any system or the installation of any additional equipment.

• Level 3 Alteration

  • Alteration where the work area exceeds 50% of the building area. If mechanical or water heating is altered part of the alteration, then the equipment space must be made electric ready for future electric equipment to be installed.

• Level 3+ Substantial Alteration

  • Alteration that modifies 50% or more of the floor area AND includes replacement of major mechanical systems AND substantial thermal envelope modifications must install electric equipment as the primary source of space and water heating. Gas appliances would still be allowed for backup space and water heating or small loads, such as cooking and drying; Substantial is defined as 50% or more.

• Construction Value (CV)

  • Construction Value as determine per City of Boulder Construction Value Guidance Document. A cost estimate must be provided with permit application.

New commercial construction projects additions (less than or equal to) ≤ $500,000 in construction valuation shall comply with the commercial energy prescriptive or performance requirements in the 2024 CoBECC. Projects (greater than or equal to) ≥ $500,000 in construction valuation shall comply with the performance requirements of C407 if new construction or section C502 if an addition and are required to achieve the applicable Energy Use Intensity (EUI). The EUI is energy use per square-foot of building area. New commercial construction is continuing to push the envelope as we move toward Net Zero Energy and Net Zero Emissions in the City of Boulder.

A new section has been added to the energy code for Additional Conservation Measures. This section helps align with the state required energy code minimum and introduces some new options as we look ahead at not just energy use reduction but overall emissions reductions. These sections have many energy efficiency credits as well as embodied carbon options to help show compliance.