Report | 2024
The Energy Code Safe Harbor Toolkit
The Energy Code Safe Harbor Toolkit: May 2026 Update
Plug-and-play energy code proposals that promote heat pumps in new buildings
A growing number of cities and states are eager to make meaningful progress on decarbonizing buildings to achieve climate targets, enhance quality of life for all residents and businesses, and improve energy efficiency. New construction poses an irreplaceable opportunity to build smart from the start: it is the most cost-effective time to improve efficiency and helps prepare the workforce to decarbonize existing homes and businesses. To do this, leaders need policies that make zero-emission new construction the norm and comply with the federal Energy Policy and Conservation Act (EPCA).
In 2023, a federal court decision introduced a new interpretation of EPCA and halted Berkeley’s all-electric new construction ordinance. As a result, in Berkeley and throughout all nine states in the Ninth Circuit, governments are now limited in how they can require all-electric new construction. While the decision does not limit city or state action in other circuits, the risk of similar legal challenges has caused concern in some jurisdictions.
As of mid-2026, every federal ruling on this question outside the Ninth Circuit has disagreed with the Ninth Circuit’s decision. Some cases remain open or have been appealed to higher courts. For the latest updates on related litigation, see the Public Health Law Center’s Litigation Tracker and commentary.
To help cities and states successfully advance zero-emission new construction for commercial and residential properties with confidence, RMI and the Public Health Law Center collaborated to release the Energy Code Safe Harbor Toolkit (the Toolkit) in 2024. In 2026, RMI updated the code language in the Toolkit to be even easier to adopt and enforce, including new options to encourage energy efficiency in new buildings when air conditioners are replaced.
What is the Toolkit? The Toolkit comes in two parts:
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Energy Choice Overlays for commercial and residential buildings (ECO): Adoptable code language designed to add fair, objective, low- and zero-emission compliance options to the 2024 International Energy Conservation Code and ASHRAE 90.1-2022. ECO includes three code language suites:
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UPDATED ECO v2: Code language that comprehensively counts heat pump efficiency toward new construction code compliance, now easier to adopt. In this update, no energy modeling or other analysis is required to customize ECO for a jurisdiction to adopt it.
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NEW: ECO Simple v1: Code language that takes a first step toward counting heat pump efficiency in new construction while minimizing complexity in adoption, training, and enforcement processes. ECO Simple adapts model code appendices that are incorporated into national code development processes and enforcement tools.
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NEW: ECO AC to Heat Pump: Code language that sets efficiency targets when simple cooling equipment is replaced in existing buildings. Code users can meet the target by installing a heat pump or equivalent energy efficiency measures.
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An issue report that describes how energy codes work, why EPCA matters, how today’s model codes fall short of what’s possible, and how ECO takes steps toward a climate-friendly code (the Report).
Who is the Toolkit for? The Toolkit was designed for jurisdiction staff and advocates across the nation who want to remove penalties for high efficiency heating appliances, like heat pumps, from the energy code. Anyone who participates in building energy code development or adoption can use the Toolkit by submitting ECO language as code proposals.
How does ECO reduce climate pollution? Surprisingly, model codes often require all-electric buildings to achieve higher energy efficiency than mixed fuel buildings. This disadvantages heat pumps, increases climate pollution, and often increases energy bills. ECO removes bias in the model codes, ensuring that builders can earn due credit toward compliance when they choose high-efficiency types of equipment like heat pumps. ECO does not require all-electric new construction.
Where can I learn more? For assistance applying ECO or adjusting it for your jurisdiction’s situation, reach out to Erin Sherman (esherman@rmi.org) at RMI. For assistance understanding the Berkeley federal circuit court decision and building electrification policy options in the context of that decision, reach out to Daniel Carpenter-Gold (daniel.carpentergold@mitchellhamline.edu) at Public Health Law Center.
A prior version of the Energy Choice Overlays was published under the title Zero Fuel Bias Code Overlays.
RMI is grateful for the generosity of the Esther A. and Joseph Klingenstein Fund, without which the 2026 update to the Energy Code Safe Harbor Toolkit would not have been possible.
