Home Assistant Presence Sensor Troubleshooting: False Occupancy, Reconnects and Room Boundaries
Presence sensors make Home Assistant feel much smarter than basic motion automations, but they also introduce new failure modes. A room can stay occupied when nobody is there, a reconnect event can turn devices on at the wrong time, or two nearby rooms can fight over the same person.
This troubleshooting guide gives you a practical runbook for false occupancy, reconnect loops, and room boundary problems using eMotion Air, eMotion Pro, eMotion Ultra, eRemote HA, HomeClaw, and iSG Display Max.
Why Presence Sensor Troubleshooting Matters
A PIR motion sensor usually answers one simple question: did movement happen recently? A mmWave presence sensor answers a more useful but more sensitive question: is a person still present, even if they are sitting still? That extra sensitivity is exactly why false occupancy and boundary logic matter.
If the room state is wrong, every connected automation can become wrong. Lights may stay on, AC may run too long, sleep mode may fail, or a local IR command may fire when nobody needs it. Good troubleshooting separates the sensor reading from the automation decision so Home Assistant can act with more confidence.
False occupancy
The room remains occupied because of fans, curtains, reflections, pets, or a delay that is too long.
Reconnect loops
A device reconnects and Home Assistant treats that technical event as a fresh presence event.
Room boundaries
Two sensors see the same person and competing automations try to own the room state.
First: Separate Sensor, Room, and Automation Problems
Before changing every automation, classify the problem. A sensor placement issue should not be fixed with a complicated YAML workaround. A room ownership issue should not be fixed by lowering sensitivity until the sensor becomes useless. A reconnect issue should not be treated as a human entering the room.
The fastest way to debug is to create three layers in Home Assistant: raw sensor state, debounced room state, and final automation action. When something fails, you can see which layer caused the wrong behavior.
Troubleshooting Table: Symptom, Likely Cause, Fix
| Symptom | Likely cause | What to check first | Recommended fix |
|---|---|---|---|
| Room stays occupied after everyone leaves | Fan, curtain, reflective surface, pet activity, or long vacancy delay. | Watch raw presence, room state, and automation delay separately. | Narrow the zone, move the sensor away from moving objects, and add a stable vacancy timer. |
| Lights turn on after WiFi or MQTT reconnect | Reconnect event is treated like a new occupancy trigger. | Check logs for device unavailable, available, and occupancy changes within seconds. | Add a reconnect fence so automations ignore the first few seconds after a device returns. |
| Adjacent rooms trigger each other | Sensor range crosses a doorway or open-plan boundary. | Compare both room sensors while standing near the boundary. | Use a room owner helper and require one room to win before device actions run. |
| AC or fan keeps running too long | Presence and comfort rules are coupled too tightly. | Check whether climate control depends only on occupied/unoccupied. | Add temperature/humidity context and a comfort hold instead of instant off behavior. |
| Presence is unstable around a desk or sofa | Sensor angle misses small posture changes or sees a moving object behind the user. | Temporarily move the sensor and compare a full work session. | Use eMotion Air for placement tests, then choose the best permanent device for the room. |
| Automation works during the day but fails at night | Mode, schedule, or sleep helper conflicts with room state. | Check helper values at the exact time the automation fired. | Separate daytime, sleep, guest, and away modes before adding more conditions. |
False Occupancy: Fans, Curtains, Pets, Reflections
False occupancy is usually not a single bug. It is a combination of room layout, sensor angle, moving objects, and automation delay. Start by watching the raw entity in Home Assistant while the room is empty. If the raw sensor stays occupied, fix placement. If the raw sensor clears but the room helper stays occupied, fix the delay or template logic.
Common sources include ceiling fans, air purifier airflow, curtains near a window, reflective doors, moving shadows, and pets crossing a low sensor zone. Do not immediately reduce sensitivity so far that the sensor no longer detects quiet human presence. The better fix is usually zone discipline and a more careful off delay.
Reconnect Loops and 3-Second Boundaries
Some high-impression queries around room presence are really support runbook queries: people want a clear rule for reconnect behavior. If a WiFi or MQTT device goes unavailable and then available, Home Assistant may receive a fresh state update. Without a guardrail, that update can look like someone just entered the room.
A simple reconnect fence solves most of this. Store the time a device returned online, then ignore presence-driven device actions for a short period. This does not hide the sensor state. It only prevents lights, AC, fans, or IR commands from firing during the technical recovery window.
# Example logic, adapt entity names to your Home Assistant setup
IF sensor_status changed from unavailable to available:
set input_datetime.presence_sensor_reconnected_at = now()
IF room_presence changed to occupied:
IF now() - input_datetime.presence_sensor_reconnected_at < 3 seconds:
do not run lights, AC, fan, or IR commands
ELSE:
run the normal occupied-room scene
IF room_presence changed to clear:
wait for a stable vacancy delay
then run the empty-room scene
Room Boundaries and Ownership Rules
Open layouts often need ownership rules. If the living room sensor and the hallway sensor both see the same person, the automation should not let both rooms command the same lights or IR devices. Create a room owner helper that decides which room currently owns the person, then let device actions follow the owner.
Ownership should use confidence, not just the newest state. A desk sensor that has been stable for five minutes should usually beat a hallway sensor that briefly saw movement. A media room scene should not be interrupted by someone walking past an open doorway.
Product Routing: Air, Pro, Ultra, eRemote HA, HomeClaw
| Problem | Best LinknLink fit | Why it helps | Product link |
|---|---|---|---|
| Need to test sensor placement before committing | eMotion Air | Battery-powered placement makes it easier to test desk, sofa, bed, and entry positions without wiring. | eMotion Air |
| Need presence plus IR in the same room | eMotion Pro | Combines mmWave presence with built-in IR for room comfort devices such as AC, fan, TV, or projector. | eMotion Pro |
| Need higher precision plus comfort context | eMotion Ultra | Uses 60GHz sensing and adds a temperature/humidity sensor cable plus built-in IR, so Home Assistant can combine presence, climate data, and local appliance control. | eMotion Ultra |
| Need a dedicated local IR endpoint | eRemote HA | Controls AC, fan, TV, purifier, and other IR devices through Home Assistant MQTT without relying on cloud scenes. | eRemote HA |
| Need private gateway logic and local AI direction | HomeClaw | Keeps Home Assistant context, automation logic, and private AI planning close to the home. | HomeClaw |
| Need a visible manual override surface | iSG Display Max | Shows room owner, current mode, comfort status, and quick override buttons for family members. | iSG Display Max |
Example Home Assistant Runbook
Use this runbook when a presence automation behaves incorrectly. The point is to gather evidence before editing too many rules.
Check the raw sensor state
If the raw presence entity is wrong, start with placement, sensor direction, and nearby moving objects.
Check the debounced room helper
If the raw sensor is correct but the room helper is wrong, tune vacancy delay, owner logic, and mode conditions.
Check reconnect history
If the problem happens after unavailable or available transitions, add a reconnect fence before device actions run.
Check room ownership
If two rooms react to one person, decide which room owns the person before lights or IR commands can run.
Check comfort dependencies
For AC, fan, and purifier logic, include temperature/humidity or mode context instead of relying only on occupied and empty states.
Room Boundary Table
| Boundary case | Risk | Decision rule | Good next step |
|---|---|---|---|
| Desk near living room | Living room lights change while someone is working. | Desk presence wins after several stable minutes. | Use eMotion Air to test angle before mounting. |
| Hallway near bedroom | Night walk triggers bright scenes. | Sleep mode limits hallway response and blocks media scenes. | Add a quiet night helper and lower brightness rules. |
| Sofa near AC line of sight | Climate rule fires from walk-through movement. | Require sofa presence plus a comfort mode or media mode. | Use eMotion Pro or eMotion Ultra when IR and presence belong together. |
| Open kitchen and dining area | Two zones both claim the same person. | Latest stable zone owns lighting, but climate stays shared. | Use a room owner helper instead of separate instant actions. |
| Device reconnect event | Lights or IR commands fire without a real person entering. | Ignore device actions for the first few seconds after reconnect. | Add reconnect timestamp helpers to the automation runbook. |
When to Use IR and Climate Context
Presence should not be the only signal for comfort devices. AC, fans, and purifiers work better when the automation also knows the room mode and climate state. That is where local IR control and eMotion Ultra's temperature/humidity sensor cable can be useful. Home Assistant can avoid turning comfort devices on or off purely because a presence state flickered.
For example, a room can remain in comfort hold while someone is quietly sitting, then step down to eco only after a stable vacancy delay and safe climate range. If the room has eMotion Ultra, 60GHz sensing, temperature/humidity data, and built-in IR can sit inside the same room automation logic.
Related Guides and Products
If you are building a full Home Assistant presence system, these articles and products are the best next steps:
- Battery Powered Presence Sensor Guide for Home Assistant Rooms
- 60GHz mmWave Sensor Placement Guide for Home Assistant Rooms
- Home Assistant Room Automation Blueprint with mmWave, IR and RF Control
- Local Control Smart Home Guide for Home Assistant: Presence, IR and RF
- Home Assistant Small Apartment Automation with Battery Presence Sensors and Local IR Control
- Home Assistant AC Automation with IR Blaster and Presence Sensors
- Meet HomeClaw: The Private AI Gateway for Home Assistant
FAQ
Why does my Home Assistant presence sensor show occupied when the room is empty?
Check fans, curtains, reflective surfaces, pets, airflow, and vacancy delays first. If the raw sensor stays occupied, adjust placement or zone direction. If only the room helper stays occupied, tune the debounce logic.
How do I stop reconnect events from triggering lights?
Add a reconnect fence. Store the time when the device returns online, then ignore lights, AC, fan, and IR commands for a short recovery window such as three seconds.
Which LinknLink device is best for room boundary testing?
Use eMotion Air for flexible placement tests, eMotion Pro when the same room needs built-in IR, and eMotion Ultra when you need 60GHz sensing, temperature/humidity data, and built-in IR together.
Can eMotion Ultra control IR devices directly?
Yes. eMotion Ultra includes built-in IR control in addition to 60GHz presence sensing and a temperature/humidity sensor cable, so it can support room comfort automations inside Home Assistant.
Should I fix false occupancy by lowering sensitivity?
Not as the first step. Lowering sensitivity too far can break quiet-presence detection. Start with placement, zone direction, room ownership, and vacancy delay.
How should Home Assistant decide which room owns a person?
Create a room owner helper. Let the most stable and contextually relevant room win before lights, climate, or IR commands run.
Debugging rule: do not rewrite every automation at once. Confirm the raw sensor state, room helper, reconnect events, and room owner before changing device actions.
Build More Reliable Room Presence Automations
Start with a placement-friendly sensor, add local IR control where comfort devices matter, and keep the room logic private with HomeClaw and Home Assistant.