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The Berkeley Decarb Tool is an open-source web application developed by the Center for the Built Environment (CBE) at the University of California, Berkeley.
It supports building decarbonization planning by enabling users to assess and compare the long-term operational carbon emissions of HVAC systems under different configurations and grid emission scenarios.
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Location-based load profiles: Select representative building heating and cooling load profiles by climate zone, building type, and vintage — or upload your own.
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HVAC equipment comparison: Build and customize multiple system configurations using an expanding library of common equipment types (e.g., water-to-water heat pumps, air-to-water heat pumps, boilers, chillers, and hybrid systems).
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Emission scenario modeling: Evaluate performance across multiple grid scenarios (e.g., MidCase, High RE) and years using NREL Cambium data.
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Flexible emissions accounting: Incorporate short-run marginal weighting, refrigerant leakage, and gas leakage assumptions.
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Interactive results: Compare energy use, emissions, and key performance indicators across equipment and emission scenarios to support early-stage decision-making and sensitivity analyses.
The tool is designed to bring consistency, transparency, and scientific robustness to HVAC decarbonization studies — reducing reliance on proprietary or ad hoc internal modeling approaches.
While the tool is still under development, we have set up a short documentation outlining underlying calculations here.
In the near future, we are planning to add the following features or improvements to the tool.
- Utility cost calculations
- N+1 redundancy in sizing calculations to account for additional refrigerant leakage
- Water-cooled chillers with PLR-based capacity and COP curves
- Cooling tower water use calculations
- Outdoor air temperature-based capacity and COP curves for air-cooled chillers
- Varying refrigerant leakage rates for different types of equipment
- Exhaust air heat recovery
- AWHPs with heat recovery
- Sizing AWHPs based on heating or cooling instead of heating only
- Fuel switching evaluation (based on grid emissions and equipment COP)
- Load shifting evaluation (thermal energy storage)
Please find open issues for a full list of proposed features (and known issues).
Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.
If you have a suggestion that would make this better, please fork the repo and create a pull request. You can also simply open an issue with the tag "enhancement". Thanks!
- Fork the Project
- Create your Feature Branch (
git checkout -b feature/AmazingFeature) - Commit your Changes (
git commit -m 'Add some AmazingFeature') - Push to the Branch (
git push origin feature/AmazingFeature) - Open a Pull Request
Distributed under the GNU General Public License. See LICENSE_GNU_GPLv3 file for more information.
For general feedback and anything related to the codebase, the tool functionality or underlying calculations, please check the documentation, review/add issues or use the Discussions page.
We would like to acknowledge the following resources:
- This tool uses the 2024 Cambium dataset: Gagnon, Pieter, Pedro Andres Sanchez Perez, Julian Florez, James Morris, Marck Llerena Velasquez, and Jordan Eisenman. 2025. Cambium 2024 Scenario Descriptions and Documentation. Golden, CO: National Renewable Energy Laboratory. NREL/TP-6A40-93005. https://www.nrel.gov/docs/fy25osti/93005.pdf.