[APP][Pro] HUUM UKU Sauna

Apps
1

HUUM UKU Sauna gives you full control over your HUUM sauna heater, including

the settings the official HUUM app for Homey leaves out — target humidity

above all.

What is this app?

An independent Homey app for HUUM sauna heaters with the UKU WiFi controller. It talks directly to HUUM’s cloud API — the same one the official HUUM mobile app uses — so everything that API exposes is available on Homey too, not just the subset the official Homey app covers.

Why this app exists

The official Homey app for HUUM can’t set target humidity, even though HUUM’s own mobile app can. I reported that gap to Athom in June 2025; as of today it still hasn’t made it into the official app, so I built this one instead.

What can it do?

  • Settable target humidity (the official app only shows it, can’t set it)
  • A no-water alarm for the steamer
  • A safety cut-out / fault alarm
  • A remote-start-blocked sensor — separate from the door sensor, shows when the UKU’s own remote-safety confirmation is blocking a start
  • A “finishing soon” timer capability
  • 3 profiles (temperature + humidity presets), startable from the device tile, a Flow, or the dashboard widget
  • A scheduled start with optional auto-off. HUUM’s API has no booking endpoint, so this runs entirely on Homey — it survives a restart, and a start missed by more than 30 minutes is dropped rather than fired late
  • Per-session energy and cost, fed by a kW estimate, a linked power meter (e.g. a Shelly), or a value pushed from a Flow
  • A dashboard widget with live status and quick-start buttons
  • Steamer and light are auto-detected during pairing, so you only see the controls that actually apply to your setup

Flow Cards

When (triggers):

  • The sauna reached its target temperature
  • Remaining time drops below (x) minutes
  • Maximum heating duration almost reached (based on the UKU’s own auto shut-off timer, not the target temperature)
  • The current temperature changed (Homey’s own measure_temperature defaults
    only offer threshold cards, not a plain “changed” one — this app adds it)
  • Remote start became blocked / available
  • A sauna session ended (with duration, temperature, humidity, energy and
    cost tokens)

And (conditions):

  • Remaining time is / is not below (x) minutes
  • A start is / is not scheduled
  • Remote start is / is not blocked

Then (actions):

  • Start the sauna at a temperature and humidity
  • Start the sauna with a profile
  • Schedule a start on [date] at [time] with a profile
  • Cancel the scheduled start
  • Save the current settings as a profile
  • Set the sauna’s measured power (for the energy tab, if you feed it from a
    Flow instead of a linked meter)

(Plus everything Homey generates itself from the standard capabilities — turn
off, set temperature/humidity, the light, door/alarm triggers, and so on.)

Setup

Pairing uses the same email and password as the HUUM app. Everything runs against HUUM’s cloud (sauna.huum.eu) — there is no local/LAN protocol for the UKU, so this can’t be a fully local app. It uses the homey:manager:api permission only for the in-app power-meter picker (so you can link a real energy meter); no data leaves your Homey beyond what talking to HUUM’s own API requires.

About this app

I built this for my own sauna after reporting the target-humidity gap to Athom and not seeing it get picked up. Built with Claude’s assistance.

Currently on the Test channel:

Support the Development

If this is useful to you: PayPal.Me

2

Settings guide and FAQ

App settings (Apps → HUUM UKU Sauna → Configure)

Overview tab

Everything the API currently reports, a refresh button with a timestamp, and the scheduled start (set a time, a profile or a temperature/humidity pair, and an optional auto-off). If remote start is currently blocked, the form warns you right there before you schedule a start that would fail. Whether a start is scheduled, and when, is also on the device tile itself (huum_booking_status).

Settings tab

The two poll intervals (active/idle) and the the auto-shutoff warning threshold, then the 3 profiles (name, temperature, humidity each).

Statistics tab

Session and energy totals, average per session, a recent-sessions list, the heater-power source (estimate / linked meter / Flow), and the electricity price used for the cost figures. A scheduled start that failed or was dropped (door open, remote blocked, login failed, missed because the app was offline, …) shows up in that same list with its reason, not just as a fleeting notification.

Support tab

A link to this forum thread.

Device settings (the gear icon on the device)

Read-only sauna info, a toggle for the “check the water before heating” push notification, and Sensors/hardware: whether this sauna actually has a water-level sensor and a door sensor (auto/present/absent). Setting either to “absent” hides the matching alarm; for the door sensor it also skips the “don’t start with the door open” safety check, since a heater with no door contact would otherwise always report the door as open.

FAQ

Does this replace the official HUUM app?

No, they can run side by side — this app just exposes what the official one doesn’t.

What if my sauna has no steamer?

Detected automatically during pairing (based on the settings of the UKU); humidity control and the no-water alarm simply aren’t added.

Can I control more than one sauna?

Yes — a HUUM account maps to exactly one sauna, so pair again with the second account to add a second device.

Is any of this processed locally?

No. The UKU has no local/LAN protocol, so every command and status read goes through HUUM’s cloud, same as the official app.

Why does it need the homey:manager:api permission?

Only so the Statistics tab can offer a dropdown of your other measure_power devices to link as a real energy meter. Nothing else uses it.

What does “remote start blocked“ actually mean?

The UKU sometimes requires someone to confirm safety on the physical control panel before it will accept a start command sent remotely. This app surfaces that as its own sensor and Flow trigger/condition, separate from the door-open alarm, and warns about it right in the scheduling form too.

How accurate is the energy/cost tracking?

Depends on the source you pick in Settings: a duty-cycle estimate (no extra hardware), a linked real power meter (most accurate — kWh is taken from the meter’s own counter delta), or a value you push in from your own Flow.

Does the scheduled start survive a Homey restart?

Yes, a booking missed by more than 30 minutes is dropped rather than fired late, and any failed or dropped attempt is recorded in the session history so it doesn’t go unnoticed.

Where do I report a bug or request a feature?

Reply in this thread, or open a GitHub issue if you want it tracked: Issues · RickD-CH/com.rickd.huum · GitHub