Energy Conservation Code

The 2020 City of Boulder Energy Conservation Code is a localized version of the 2018 International Energy Conservation Code that is 20% more efficient than the national code. The city updates our energy code on a three-year cycle with the goal of attaining net-zero energy, outcome-verified code by 2031 to meet broader city-wide climate commitment goals.

As of July 1, 2020, all projects must be designed to meet the 2018 ICC suite of codes and the 2020 City of Boulder Energy Conservation Code.

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 percent 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 percent 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).

The significant changes being proposed for the energy code are described in detail in the April 16, 2019 City Council Memo. The presentation can be found at this video link. The most significant changes being proposed are:

More stringent Energy Rating Index (ERI) requirements

An ERI score is the same as 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 2020 code, new construction and major alteration projects must demonstrate compliance with Boulder’s energy code by using the prescribed ERI compliance path. In the 2020 code ERI scores are getting more stringent compared to the 2017 code.

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This figure illustrates the new ERI scores required by the 2020 code for new construction. Note all new homes over 3,000 square feet are required to achieve net zero.

Envelope Backstop

With the cost of renewables decreasing, some projects simply deploy large solar arrays to achieve building performance requirements instead of investing in basic building efficiency. With this code update, an envelope backstop is being introduced that will ensure all elements of the building enclosure: windows, walls, floor slabs, roof assemblies, and doors are energy efficient. Each project will need to comply with prescriptive building envelope requirements in the energy code.

Renewable Offsets

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.

Construction & Demolition Waste Requirements

For over a decade, Boulder’s codes have included construction and demolition waste requirements for residential projects. With this code update, these requirements are being expanded to commercial projects. Additionally, improvements are being made to the code provisions and enforcement practices, including the addition of a requirement for a refundable deposit at the time of permit application.

Code Provisions for Alterations

Currently, the 2017 code requires additional energy efficiency improvements be made when renovating homes. The requirements are currently based on the construction value of the project. The 2020 code continues to require energy efficiency improvements for home renovations; however, the requirements are now triggered by the level of alteration as defined in the 2018 Existing Building Code.

Energy Use Index (EUI) Performance Path

The 2020 code introduces an EUI target compliance path that allows Boulder to transition towards outcome-based compliance, which staff and our consultants believe will be necessary to meet the City’s building energy efficiency goals.

Solar Mandate

To meet long-term NZE performance goals, it is necessary to encourage the deployment of renewable energy at the project level. The 2017 code mandates solar-ready requirements. In the 2020 code, at least 5% of commercial building energy use be supplied by on-site renewables for new construction.

Pilot for Outcome-Verified Code Path

The 2020 code provides an outcome-verified code compliance path. Ultimately, the 2031 goal of Boulder’s energy code is to set standards that will result in buildings that are NZE, not just in theory and as designed, but verified through metered data once the building is constructed, commissioned, and occupied. The outcome path included in the 2020 code would achieve this goal for projects that opt into this path.

Electric Vehicle (EV) Charging Requirements

In 2017, provisions were added to the code requiring commercial and residential projects provide EV charging infrastructure. Because technology has evolved and the demand for EV charging is better understood, the 2020 code clarifies and adjusts these requirements for commercial projects.

Alteration Levels

New residential construction projects (less than) < 500 square feet shall comply with the residential energy efficiency mandatory and prescriptive requirements in the City of Boulder Energy Conservation Code. Projects greater than or equal to 500 square feet shall comply with the mandatory requirements and are required to achieve the applicable Energy Rating Index (ERI) . The ERI is the non-trademark equivalent to 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.

The larger the house, the lower the ERI (increased efficiency). Houses larger than 3,000 square feet are required to be NZE in the 2020 energy code. Further explanation can be found in the 2020 City of Boulder Energy Conservation Code, Section R406
.

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

Alteration Levels

Staff is in the process of scheduling training sessions for design professionals and applicants. The COVID-19 crisis may delay scheduling these session.