Privacy

The short version: your electricity data is read in your browser and never sent to us. We don’t use tracking cookies and there are no accounts.

Your half-hourly CSV

The file you upload on the “Your usage” step is parsed entirely in your browser. It is summarised into an average-day profile and kept only in your browser tab’s session storage, which is cleared when you close the tab or press “Start over”. The raw readings are never stored or transmitted.

Postcode and tariff

Your postcode is sent to two services to run the estimate: postcodes.io (to get coordinates) and the EU PVGIS service via our server (to get local solar yield). We cache the yield result by location so repeat lookups don’t hit PVGIS again; we don’t log who asked for it. Your tariff rates stay in your browser alongside the usage summary.

Analytics

We use Vercel Analytics to count visits and see where people leave the four-step flow. It is cookieless, sets no persistent identifier, and the events we record carry only coarse values — a step name, whether a lookup succeeded, a rounded number of days of data. No postcode, no consumption figures, nothing that identifies you.

The feedback form

If you send feedback, your message (and your email address, if you choose to give one) is emailed to us so we can read and reply. If you tick “attach my inputs” — off by default — the message also includes your postcode, the usage summary figures and your tariff, to help us reproduce a problem. It never includes your raw half-hourly data. These emails sit in our inbox; tell us if you want yours deleted.

Contact

Use the feedback button on any page, or the email address it is configured to reach. This page will move to a fuller notice before any wider launch.

Last updated 9 September 2026.