Helios
Make your energy visible, in 2.5D.
The Home Assistant card that turns your Energy dashboard into a living, real-time 2.5D scene of what your home produces, stores and consumes, across the sun's daily arc. With or without solar panels.
Helios Forecast
Know what the sun will bring.
A self-learning solar production forecast that runs entirely on your own Home Assistant. It feeds the Energy dashboard, learns from what your panels really do, and never sends your data anywhere.
Two projects. One belief.
Energy you can see is energy you can act on.
The three values behind every feature.
I don't take them lightly: they decide every feature I build, and every one I walk away from. They're the same principles the Open Home Foundation fights for, and the whole reason for Helios: to make energy tangible and easy to grasp, so we finally feel what a chance it is to have it, and stop taking it for granted.
- Privacy & open source
Your data never leaves home.
Helios is fully open source and runs in your browser. No server, no account, no telemetry: your solar, battery and grid figures stay inside your own Home Assistant.
Everything on screen comes from open, keyless data, Open-Meteo and OpenStreetMap via OpenFreeMap, rendered on your device from a rough location, never your exact GPS coordinates.
- Simple, configurable, plug-and-play
Plug it in, and make it yours.
type: custom:helios-cardOne line. That's the whole config.
Helios reads the Energy dashboard you already set up, so it works out of the box, with or without solar. Then make it yours: theme the map, group your devices, show or hide any chip, or strip it back to a bare sun.
- Performance & efficiency
Built to run on the hardware you already own.
The greenest device is the one you never replace. So Helios paints its whole scene with a lightweight vector engine, plain SVG over open vector tiles, no WebGL, no game engine, no heavy framework.
It stays fluid on years-old phones and tablets: less to download, less to compute, less e-waste.
I still believe we can turn this around.
I'm Jérôme, 44, the developer behind Helios. After years across the whole stack, backend, frontend, 3D, games, embedded, I wanted to build something that actually matters to me.
A card won't save the planet, I know. But guilt and numbers nobody reads change no one: people change when they can finally see what's happening in their own home. That's the whole point of Helios, make energy visible, tangible, even beautiful, so acting on it stops feeling like a duty and starts feeling obvious.
Helios is free and open source, built by one person in the open.
Helios is an independent community project, not created by, endorsed by, or affiliated with the Open Home Foundation or Home Assistant. Home Assistant and the Home Assistant logo are trademarks of the Open Home Foundation.
ReikanYsora - Jérôme CREMOUX - 2026