Privacy Policy
Controller: Philippe Froehly, Schupfarterstrasse 6, 5074 Eiken, Switzerland · hallo@lumencircle.ch
Lumen Circle has no servers. What the app knows about your home is stored on your device and stays there. You need no account, you never sign in anywhere, and nothing is analysed.
What data the app needs
- Home (HomeKit)
- Rooms, devices, names, scenes and sensor readings. The app reads them straight from HomeKit and writes switching commands back to it. None of this leaves the device.
- Location — leaving alert
- This is the only purpose for which the app asks for your location at all. If you switch the feature on, you set your home location once. That location is stored on the device and never leaves it; iOS then watches the zone and wakes the app when you leave it. Out of the box, the feature is off.
- Hue Bridge on the home network
- For the energy meter, the app talks directly to your Hue Bridge on the home network, encrypted and with it alone: it checks the bridge’s certificate and accepts no other. The key the bridge hands out after you press its button is stored by the app in the device’s keychain; it does not leave the device. For this, iOS asks once for access to the local network. You can disconnect at any time in Settings.
- Finding the bridge — Signify
- The app first looks for the bridge on the network itself. If it finds none there, it asks Signify’s directory service (discovery.meethue.com) once. The request carries no content; as with any call over the internet, the service sees the public address of your connection and answers with the bridges behind it. Nothing from your home goes with it, and none of it is stored.
- Consumption profiles — Powercalc
- Hue lamps do not measure their own consumption. For every lamp model the bridge reports, the app fetches a measured profile once from the open library of the Powercalc project (api.powercalc.nl, with the measurement series from GitHub). What goes out is the model identifier as printed on the box, such as “LCT015”, and nothing else: no name, no location, no identifier for your home, and not how many lamps you have. Each model is looked up at most once, and the result stays on the device. Offline, the app works with an estimate and says so. The data is available under the MIT licence.
- Microphone — Party mode
- Party mode measures the volume to keep the lights on the beat. Only the level is analysed, directly on the device. No recording is made: the sound is discarded as soon as the number has been read from it.
- Notifications
- Threshold, leaving and energy alerts are generated locally on the device. There is no push service and no server of ours behind them. The energy alerts are off out of the box.
- Settings
- Palette, thresholds, the order of the tiles, your electricity price, the energy alerts, the home location for the leaving alert and the state of the trial are kept in the app’s local settings.
- Shared folder for widgets and complications
- A widget runs for seconds rather than continuously, so it cannot ask HomeKit itself. The app therefore places four files in a folder that only it and its own extensions can read: a snapshot with room names, light states, outdoor temperature and CO₂ value, a measurement history of the last 24 hours for the charts, the readings of the energy meter (hourly for 90 days, daily for five years) and the learned lamp profiles. All of it stays on the device and disappears with the app.
- Apple Watch
- The watch app talks to HomeKit itself and keeps its own snapshot on the watch. Nothing of ours travels between phone and watch; iOS mirrors notifications to the wrist on its own.
- Shortcuts and Siri
- Rooms and scenes are offered to iOS as options for Shortcuts so that Siri can switch them. What Siri processes of your request depends on Apple’s settings, not ours.
- Live Activity on the Lock Screen
- A running room timer appears as a Live Activity. It shows the room name and the remaining time and runs through iOS on the same device.
Subscription
The subscription goes through the App Store. Apple handles payment and receipt; the app only learns whether it is running, not who took it out. There is no other payment provider. Apple’s privacy policy governs how Apple handles this data.
No tracking
There is no advertising identifier in the app and no library that analyses your behaviour. Crash reports go to no one. The app never asks for tracking permission, because there is nothing to track.
This website
It sets no cookies, and no analytics tool runs here. Two things you should know all the same: the site is hosted on GitHub Pages, and like any web server the host logs the requests along with the IP address. The home page loads the Hanken Grotesk typeface from Google Fonts; there too the provider sees the IP address of your connection. Both concern this website only, not the app.
If you write to us
A support mail to hallo@lumencircle.ch arrives in an ordinary mailbox. The address, the content and any attachments stay there while the matter is open and are deleted afterwards, at the latest after two years. None of it is passed on, and we do not use it for advertising.
Your rights
Apart from your support correspondence, no personal data ends up with us. You can ask for access to it at any time, have it corrected or deleted — a mail is enough. For everything else we can neither give access nor delete anything: there is simply nothing there. Everything the app has stored disappears as soon as you delete it from the device, or when you choose Factory reset in Settings. That also clears the Hue Bridge key from the keychain.
Contact
Version of 5 September 2026.