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Sensor availability

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Jan edited this page Aug 21, 2026 · 5 revisions

Sensor availability

Brunata sensors stay available for as long as they have received at least one valid reading. They do not go unavailable when a poll fails.

This is deliberate, and it has a visible consequence: a sensor can sit on the same value for hours or days without anything being broken. This page explains when that is normal, and how to tell the difference.

Why sensors don't go unavailable

Every Brunata sensor uses state_class: total_increasing, which feeds Home Assistant's Long Term Statistics — the data behind the Energy dashboard and long-range history.

Long Term Statistics are written as the state changes. If a sensor goes unavailable, no statistics are recorded for that period, and the gap cannot be filled in afterwards. Restoring it would mean re-inserting historical statistics by hand, which Home Assistant deliberately makes difficult.

A Brunata outage of a few hours would therefore leave a permanent hole in a dataset that is meant to span years. Holding the last known value costs nothing by comparison: meters report infrequently anyway, so a held value is usually still the correct one.

Telling stale data from fresh data

Every sensor carries a reading_date attribute holding the date of the last reading Brunata's API returned.

Fresh: reading_date advances as new readings arrive.

Stale: the sensor value looks normal, but reading_date has stopped moving while the state itself hasn't changed either.

To see it, open the sensor in Developer Tools → States, or add it to a card:

type: entities
entities:
  - entity: sensor.brunata_water_12345_consumption
    secondary_info: last-changed
    type: attribute
    attribute: reading_date
    name: Last reading

Alerting on stale data

If you want to be told when readings stop arriving, use a template sensor on reading_date rather than on availability:

template:
  - binary_sensor:
      - name: "Brunata readings stale"
        state: >
          {{ (now().date() -
             (state_attr('sensor.brunata_water_12345_consumption',
                         'reading_date') | as_datetime).date()).days > 7 }}

Adjust the threshold to your meter. Heat cost allocators and water meters often report only every few days, so a short threshold will produce false alarms.

What a real outage looks like

A failed poll is logged, not surfaced as unavailability. To see what the integration is doing:

  1. Settings → Devices & Services → Brunata
  2. Three-dot menu → Enable debug logging
  3. Reproduce, then disable it again — Home Assistant offers the log for download

Two failure modes are handled differently:

Situation Behaviour
Cannot reach Brunata Last known values are kept, sensors stay available
Brunata returns an error The update is marked failed; values are still held
Credentials no longer accepted Home Assistant prompts you to re-authenticate

Only the last one requires action from you.

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