Presence detection you can trust—within limits

Separate property, person and room presence

Property presence answers whether anyone is probably home. Person presence links that state to an individual and may include zones such as work or school. Room occupancy asks whether a local space is in use. These are different questions: a phone connected to Wi-Fi does not identify the occupied room, and a living-room PIR pulse does not identify a person.

Start with the decision you need. Arrival lighting may use a person entering the home zone plus darkness. Whole-home “away” behavior should aggregate every relevant person and wait through tracker delays. Room comfort should use local occupancy and retain manual control. The larger the consequence, the more independent evidence and recovery paths it deserves.

Understand device_tracker, person and zone

A device_tracker is supplied by another integration, such as a companion app or router. It may report exact position or connection to a fixed device. A person entity can combine multiple trackers. Official behavior gives connection trackers priority while home, then position trackers; away from home, position trackers take priority. This reduces common transition errors but does not make the result instantaneous.

Zones are geographic regions used by people and trackers. The zone state is the number of people currently inside, while zone triggers can react to entry, exit or occupancy changes. Use a zone radius that reflects GPS accuracy and the actual approach path. Very small zones can flap; very large zones can trigger before arrival.

Compare signals by delay, scope and privacy

Scroll horizontally to compare every column.

No row is universally superior. Combine only what improves the decision, document retention, and avoid collecting precision you do not need.

Build an away decision that can admit uncertainty

A cautious away automation triggers only after the home zone has been unoccupied for a stable interval. It checks that every relevant person is not home and that their states are neither unknown nor unavailable. It then performs reversible convenience actions—turning off selected lights or reducing media—not security-critical claims. A notification can report what changed.

Restart caveat: the ten-minute for timer does not survive a Home Assistant restart or automation reload. In this reversible example, a reset delays the shutdown until a complete new interval has passed. If the deadline itself must persist, use the documented input_datetime timestamp pattern instead of relying on an in-memory for timer.

Do not automatically unlock a door because a single tracker enters a zone. GPS can jump, credentials can be compromised and a phone can arrive without its owner. Use secure access-control hardware and explicit authenticated action for entry. Likewise, occupancy data can support alarm awareness but cannot replace certified detection or monitoring.

alias: "Home empty — reversible shutdown"
triggers:
  - trigger: numeric_state
    entity_id: zone.home
    below: 1
    for: "00:10:00"
conditions:
  - condition: template
    value_template: >-
      {{ states('person.ada') not in ['home', 'unknown', 'unavailable']
         and states('person.sam') not in ['home', 'unknown', 'unavailable'] }}
actions:
  - action: light.turn_off
    target:
      area_id: living_room
  - action: notify.send_message
    target:
      entity_id: notify.household
    data:
      message: "Home appeared empty for 10 minutes; living-room lights were turned off."
mode: single

Collect less location data, expose less system

Exact coordinates, named zones and room occupancy reveal routines. Give login access only to people who need it, use strong unique passwords and multi-factor authentication, keep Home Assistant current, and use a secure remote-access method instead of exposing an unprotected instance directly. The official security guidance notes that secrets.yaml centralizes values but does not encrypt them.

Disable trackers you do not use and prefer a coarse home/not-home signal when exact position adds no value. Avoid screenshots or exported traces that reveal coordinates. Review any third-party integration’s data path and account permissions. Presence automations should be explainable to every person whose data they use.

Validate transitions over ordinary days

Record arrival and departure times from entity history for several normal journeys. Look for delayed Wi-Fi disconnects, GPS jumps, phone power-saving gaps and states after a Home Assistant restart. Test two people leaving at different times and one person returning quickly. For room sensors, test stillness, open doors, pets and adjacent movement.

Set the stable period from observed worst cases plus a reasonable margin, not from a forum default. If you create a template occupancy entity, expose an “uncertain” diagnostic alongside it instead of hiding missing inputs. Review the logic after changing phones, routers, sensor placement or integrations.