Licenses & Data Sources
We use only freely-licensed data and open-source software, with attribution.
Blank charts published for download
The blank psychrometric charts under Downloads are our own drawings, not a reproduction of anyone else’s chart. Free to use, including in commercial projects and in teaching.
You may print them and hand out the printouts; draw on them, which is what a blank chart is for; place the drawing into your own documentation and print it inside your own title block; and pass the files on unchanged.
You may not sell the files, and you may not pass them on as your own with the source identification stripped out. That restriction is about handing the files on — not about what you draw with them or where you put the drawing.
This is deliberately not a Creative Commons licence: CC BY would require attribution on every printout, which nobody does, and CC BY-ND would forbid drawing on the sheet. The terms live here rather than on the sheets themselves: a single line short enough for the footer could not say all of the above without discouraging exactly the use the charts are drawn for.
Climate data
Design climate values shown in the application are derived from the following freely-licensed sources. Each source requires attribution:
| Source | Used for | License / attribution |
|---|---|---|
| Open-Meteo | City search, historical archive (ERA5) | CC BY 4.0 — “Weather data by Open-Meteo.com” |
| GeoNames | City elevations in the altitude table on the downloads page | CC BY 4.0 — GeoNames |
| Copernicus / ERA5 | Reanalysis for design percentiles | “Generated using Copernicus Climate Change Service information” |
| JRC PVGIS | Typical Meteorological Year (TMY) | © European Union — PVGIS |
| GeoSphere Austria | Austrian station design conditions | CC BY 4.0 — GeoSphere Austria |
| DWD | German station design conditions | GeoNutzV — Deutscher Wetterdienst (opendata.dwd.de) |
| EPW (user upload) | User-supplied weather file | Licensing is the responsibility of the uploading user. |
Reanalysis-based values (ERA5) use a coarser grid than station measurements; extreme values (especially winter) tend to be milder. Each source is clearly labelled in the app.
Technical standards
The application implements calculation formulas from the standards below. Physical formulas are not subject to copyright; the verbatim tables and text of the standards are, and are not reproduced in the application.
- ASHRAE Handbook — Fundamentals (psychrometric relations)
- ASHRAE 55 / ISO 7730 (thermal comfort, PMV/PPD)
- EN 16798-1 / -3, EN 15251 (indoor environment, ventilation)
- ISO 7243 (WBGT), EN 12831 (heat loss), ISO 14644 (cleanrooms), VDI 6022 / 3803
Fonts
- Noto Sans — SIL Open Font License 1.1
Open-source software
PsychroView is built on open-source libraries licensed under permissive licenses (MIT, ISC, Apache-2.0, BSD). Key libraries include React, D3, math.js, i18next, Hono, Drizzle ORM and Zod. The full machine-generated list of third-party packages and their licenses is available on request and shipped with the application build.
Trademarks
“PsychroView” is our own mark. “Mollier” and “Carrier” diagrams are used as generic names for psychrometric chart types. All other product names are trademarks of their respective owners.