EnergyPlus has rich support for hourly and sub-hourly reporting, but as a model becomes larger and more complex, the simulation output size can become unwieldy for many existing tools. This can result in prohibitively long load-times just to view your simulation results.

Timestep attempts to be a better solution, offering a clean, user-friendly and near-instanteous querying interface, as well as modern data visualization capabilities. It accomplishes this by using the EnergyPlus SQLite Output reporting, and can load and visualize very large simulation output files in seconds, rather than minutes.

• Native support and install packages for MacOS and Windows.
• Heatmap, Multi-Line, Scatter Plot, Histogram, and Statistical Summary outputs
• CSV and clipboard export
• Saved sessions and multiple views within a session
• Support for multiple simulation files
• Auto-detection and parsing of BND files for more contextual IP units conversion.

• Open EnergyPlus .eso files directly. ESO output is converted to SQLite on first open and cached, so models run without "Output:SQLite" work with no re-run. Meters are recovered too — both those embedded in the .eso and meter-file-only ones from a sibling .mtr — and the Avg/Sum variable type is restored from a sibling .rdd.
• Runs in a browser. The same app also builds as a static site that runs SQLite in the tab via WebAssembly (sql.js): drop a .sql or .eso on the page, with nothing uploaded and no install.
• IP/SI unit resolution from the .bnd file. m³/s flows resolve to cfm or gpm by the node fluid type, with scfm for standard-density air flows; units without a real IP conversion stay in SI rather than showing a wrong label.
• Data-quality warnings on load. The Loaded Files dialog flags fidelity caveats — flows defaulted to cfm for lack of a .bnd, cfm/gpm guessed from a variable name, or variables shown in SI because no IP conversion exists.
• Dark and light theme.
• Linux install packages (.AppImage, .deb, .rpm), in addition to MacOS and Windows.

1. Download the installer for your platform from the latest GitHub Release — macOS (.dmg), Windows (.exe or .msi), or Linux (.AppImage, .deb, .rpm).
2. Run the installer and launch "timestep".
3. The app is not yet code-signed: on Windows, select "More Info" then "Run Anyway" at the "Windows Protected Your PC" pop-up; on Mac, see opening apps from unidentified developers (right-click the app and choose Open).
4. Point it at an EnergyPlus run: either the eplusout.sql written with "Output:SQLite, SimpleAndTabular" in the IDF, or the raw eplusout.eso directly — no re-run needed.
5. Click the "Load Files" button, or drag .sql / .eso files (with their sibling .bnd for cfm/gpm units) onto it.
6. Start exploring your model results!