🔥 Smart Preheat — "ready at 18:00"
Switch the heater on automatically, just in time so the sauna is ready at your target moment. Use the new "Next session" datetime entity or the harvia_sauna.ready_at service — the integration computes when the heater must start.
- Learned heating model: the heat-up rate is learned per 5 °C bucket (EWMA). Door-open phases, temperature dips and the thermostat regulation zone are excluded from learning, so only real heating capacity is used. Persisted across restarts.
- Seed profiles by stone mass (high/medium/low): works from day one, even uncalibrated. The high-mass profile mirrors measured Legend 10.8 kW data (~55 min for 22→60 °C) and self-corrects after the first real heat-up.
- Robust start: the start time is recomputed every 15 min (cabin temperature drifts). After switching on, the heater is verified after 60 s with up to 3 retries. On definitive failure: a
harvia_sauna_preheat_failedevent and a persistent notification — important for Xenio, where remote start can be blocked after a door opening. sensor.planned_startexposes the computed start time and the model's calibration state; the safety buffer is configurable (default +5 min).
🎚️ Sauna presets (climate presets)
Up to 3 presets (name/temperature/duration) in the options — they appear as preset chips on the thermostat card. One tap sets target temperature and duration (it deliberately does not start the heater). Backfills the profile feature the Xenio lacks natively.
📊 Statistics
sensor.last_session_energy— kWh of the last session (estimated on Xenio)sensor.sessions_week— sessions this week (reset on Monday)sensor.records— total sessions, with hottest/longest session as attributes
All restored across restarts.
🌐 Connectivity
binary_sensor.cloud_connection (diagnostic) reports the cloud/WebSocket status — automations can stay quiet during a cloud outage instead of fighting unavailable states.
Upgrade
No breaking changes. All features are opt-in via the options flow. New platform: datetime. All 19 languages fully translated.