Retro Calc

RetroCalc is an ASHRAE Level 2-compliant energy, water, and decarbonization model for multifamily buildings. It was built by New Ecology, Inc. to make rigorous retrofit analysis fast enough for real-world technical assistance.

https://newecology.github.io/RetroCalc/

https://github.com/newecology/RetroCalc

This is the open-source backend of RetroCalc. There is also a desktop UI build distributed separately; this repo is the engine and everything the UI does is reachable from the MATLAB command line via a small number of well-documented classes and helpers.

What you can do with it

  • Historical Energy Analysis (HEA) — regress utility bills against degree days to split a building's actual use into heating / cooling / DHW / base load, per fuel.

  • Level 2 model — compute monthly space heating, cooling, DHW, lighting, equipment, fans, pumps, and appliance energy from component-level inputs (ASHRAE Level 2 depth).

  • Calibrate the model to real utility bills to tune mechanical efficiencies and schedules.

  • Model ECMs and Packages — define Energy Conservation Measures (efficiency upgrades, equipment swaps, setpoint changes, insulation, etc.) and see cumulative savings across electricity, gas, oil, propane, water, cost, and CO₂.

  • Define ECMs entirely in Excel — no MATLAB code required to author measures. Drop-in template with Excel dropdowns included.

  • Export per-ECM Level 2 breakdowns to a single Excel workbook for QC or deliverable-ready savings tables.

Too see more information on RetroCalc, including installation instructions, visit https://github.com/newecology/RetroCalc