BACnet IP Integration for Home Assistant

Connect your building automation system to Home Assistant — no YAML, no hassle.
Monitor sensors, control outputs, and automate your BACnet/IP devices through a simple GUI.

HACS Compatible · GUI-only setup · Real-time COV updates · ASHRAE 135 compliant

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What does this integration do?

This custom integration lets Home Assistant talk to BACnet/IP devices — the protocol used in professional building automation for HVAC, lighting, access control, and energy management.

In plain terms: if your building has BACnet controllers, thermostats, sensors, or actuators, this integration brings them into Home Assistant so you can monitor and control them from your dashboard, automations, and scripts.

No YAML configuration required. Everything is set up through the Home Assistant GUI.

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Features at a glance

• Three-step setup wizard — network → discover devices → select objects
• Automatic device discovery — finds BACnet devices on your network via Who-Is / I-Am
• Cross-subnet support — reach devices on other VLANs through BBMD / Foreign Device Registration
• Real-time updates via COV — Change of Value subscriptions for instant state changes, with automatic polling fallback
• Configurable COV increment — control how sensitive COV notifications are for analog objects
• Read and write — monitor sensors and control outputs with proper BACnet Priority Array handling
• Device identity — automatically reads vendor name, model, and firmware version from the device
• Custom device naming — choose your own device name during setup
• Flexible entity naming — use BACnet objectName or description for display names
• Per-object customization — override the entity type or COV setting of individual objects (e.g. make a sensor into a number)
• Selective import — only import the objects you actually need
• Configurable write priority — per-device select entity to change the BACnet write priority (disabled by default)
• Relinquish & one-off writes — bacnet.relinquish and bacnet.write_value services for full Priority Array control
• Schedules (1.0.50 beta) — BACnet Schedule objects as a sensor, with bacnet.read_schedule and bacnet.write_schedule services for the weekly schedule, exceptions and default
• Device limits & state texts — number limits from minPresValue/maxPresValue/resolution, multi-state objects as a select with their stateText labels
• Climate with a real room temperature — pair a setpoint with a separate temperature object
• Automatic outage recovery — detects network outages, reconnects automatically and tells you in Repairs when a device stays unreachable
• Reconfigure — change IP, port, BBMD or the device address without re-adding the integration
• Diagnostics — a diagnostics download and health sensors for troubleshooting
• Efficient on the network — batched ReadPropertyMultiple reads that adapt to what the device can handle
• English and Dutch user interface

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Supported object types

BACnet Object	Default entity	Writable?
Analog Input	Sensor	No
Analog Output	Number	Yes
Analog Value	Sensor	Auto-detected
Binary Input	Binary sensor	No
Binary Output	Switch	Yes
Binary Value	Switch	Auto-detected
Multi-State Input	Sensor	No
Multi-State Output	Number	Yes
Multi-State Value	Sensor	Auto-detected
Schedule (1.0.50 beta)	Sensor (current value)	Via bacnet.write_schedule

Value objects may or may not support writes — the integration auto-detects this by checking for a Priority Array during discovery.

Any object type can be changed to another entity type per object (see Customize objects). Multi-state objects can also become a select that shows their stateText labels (e.g. Off / Heat / Cool).

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Installation

Via HACS (recommended)

1. Click the HACS badge at the top of this page, or:
   • Open HACS → Integrations → ⋮ → Custom repositories
   • Paste this repository URL and select category Integration
2. Click Download
3. Restart Home Assistant

Manual installation

Copy the custom_components/bacnet folder into your Home Assistant config/custom_components/ directory and restart.

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Getting started

1. Add the integration

Go to Settings → Devices & Services → Add Integration and search for BACnet IP.

2. Configure your network

Setting	What it does	Default
Local IP address	Which network interface to use (leave empty for auto-detect)	Auto
Local port	BACnet/IP UDP port	47808
Target device address	Direct IP of a specific device (leave empty to discover all)	—
Device ID	BACnet Device Object Instance number (only needed with target address)	Auto
Enable BBMD	Turn on if devices are on a different subnet/VLAN	Off
BBMD address	IP:port of the BBMD router	—
BBMD TTL	Foreign device registration lifetime in seconds	900

3. Select your device

The integration discovers BACnet devices on the network and shows them in a dropdown. Pick the one you want to add.

4. Choose objects and name your device

• Enter a device name (pre-filled with the BACnet device name — you can change it)
• Use Select All or pick individual objects to import
• Click Submit — your entities are created and data starts flowing immediately

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Configuration options

After setup, click Configure on the integration card to adjust:

Option	What it does	Default
Enable COV	Use Change of Value subscriptions for real-time updates	On
COV increment	Minimum value change before a COV notification is sent (analog objects only). Set to 0 to use the device default.	0.1
Polling interval	How often all objects are polled, in seconds (minimum 10). Polling always runs — COV only adds faster updates in between.	30
Use description	Show BACnet description (property 28) instead of objectName as entity name	Off
Live metadata properties	Opt-in per property (object_name, description, units) for a live push update via BACnet's SubscribeCOVProperty service, instead of periodic re-reads. Each one is a separate COV subscription on the device — leave off unless you need instant updates and know your device supports it.	None
Rescan device	Re-read the device's object list to add or remove objects	—

After this page comes Customize objects. Changes take effect immediately — the integration reloads automatically.

Customize objects

The second options page lists your objects by name. Tick the ones you want to change — objects that already have a custom setting are ticked. The next page shows, for just those objects:

• type — the Home Assistant entity type (sensor, binary_sensor, switch, number, climate, or select for multi-state objects)
• COV — use COV for this object, overriding the device-wide Enable COV setting
• temperature sensor (climate objects only) — the object that provides the room temperature. Without one, the climate entity shows its setpoint as the current temperature. Just changed an object to climate? Save, then open the options again to pick its sensor.

Unticked objects use the defaults. Settings of objects you remove with a rescan are remembered and come back if you add the object again.

The default type depends on whether a Value object is commandable: a non-commandable Binary Value is a binary_sensor, a commandable one a switch. Versions before 1.0.47 could save the wrong type when you saved the options; if that happened, a Repairs message offers to reset those objects.

Reconfigure

To change the local IP address, port, BBMD settings or the device's address, open the integration's ⋮ menu and choose Reconfigure. Entities, their history and all options are kept.

Write Priority entity

A Write Priority select entity (under Configuration on the device page) is added to every BACnet device. It is disabled by default to keep dashboards clean.

To use it:

1. Go to Settings → Devices & Services → BACnet → your device
2. Find the Write Priority entity and enable it
3. Use the dropdown to select your desired priority level

Available levels: 8 (Manual Operator), 9, 12, 13, 14, 15, 16 (default — lowest)

BACnet Priority Array levels run 1–16. Priority 16 is the safest default. Use level 8 if your BAS requires Manual Operator override. The selected priority persists across HA restarts.

Live metadata properties

By default, changes to an object's metadata on the BACnet device (objectName, description, units, stateText, limits) are picked up automatically within about an hour (or sooner if the object also has active COV traffic) — see issue #26. No action is needed for this baseline behavior. The Refresh object metadata button (under Configuration on the device page) checks immediately.

If you need those changes reflected immediately, enable one or more properties under Live metadata properties in Configure. This uses BACnet's SubscribeCOVProperty service (ASHRAE 135-2012 Addendum ar) to get a live push the moment the property changes on the device — but:

• It's a separate COV subscription per property, per object. Enabling all three on 20 objects adds 60 extra subscriptions on top of the 20 already used for live values — many devices cap total COV subscriptions well below that.
• Not all devices implement this addendum. Unsupported properties/devices silently fall back to the default periodic behavior above — no error, no user action needed.

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Entity attributes

Every entity exposes additional BACnet metadata as state attributes:

Attribute	Description
bacnet_object_type	BACnet object type name (e.g. "Analog Input")
bacnet_instance	BACnet object instance number
bacnet_commandable	Whether this object supports writes
bacnet_units	Engineering units (e.g. "degrees-celsius")
bacnet_description	BACnet description property
bacnet_status_flags	BACnet status flags array
bacnet_update_method	How this entity is updated: COV or polling
bacnet_cov_increment	Configured COV sensitivity (analog objects with active COV only)
bacnet_state_text	The stateText label of the current state (multi-state objects only)

Only bacnet_status_flags and bacnet_state_text are stored in the recorder history — the other attributes don't change and aren't stored again with every state change.

An entity is unavailable when the device doesn't respond. Status flags (in-alarm, FAULT, overridden, out-of-service) don't change availability — some gateways report FAULT on every object while their values are live. Check bacnet_status_flags to see them.

Analog sensors keep the full precision of the device value; Home Assistant shows 2 decimals by default, which you can change per entity.

Diagnostic sensors

Every device also gets diagnostic sensors (under Diagnostic on the device page):

Sensor	Enabled by default
Last successful poll	Yes
COV subscriptions	No
Consecutive failed polls	No

They stay available while the device is offline, which is exactly when they're useful.

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Device information

The integration automatically reads device identity from BACnet during discovery:

• Manufacturer — from BACnet vendorName (property 121)
• Model — from BACnet modelName (property 70)
• Software version — from applicationSoftwareVersion
• Firmware version — from firmwareRevision

This information appears in the Home Assistant device registry, so you can see exactly what hardware you're working with.

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How writes work

Priority Array

All writes to commandable objects use the BACnet Priority Array (ASHRAE 135):

• Turn ON / Set value → writes at the configured priority level (default: 16)
• Turn OFF → writes inactive (0) at the same priority level — this commands the output off, it doesn't release it
• Climate → Off → relinquishes the setpoint (writes Null), so the device's own schedule or Relinquish Default takes over

The priority level is controlled by the Write Priority select entity on the device (disabled by default — see Configuration options above). Number entities use the object's minPresValue, maxPresValue and resolution as limits and step when the device provides them.

If the device rejects a write, Home Assistant shows an error message instead of silently keeping the old state.

Binary outputs use the Enumerated BACnet type (0 = inactive, 1 = active), compliant with ASHRAE 135.

Services

Service	What it does
bacnet.relinquish	Release Home Assistant's command on an object (write Null) so lower priorities or the Relinquish Default take over. Optional priority (1–16), default: the device's Write Priority.
bacnet.write_value	Write a value once at a chosen priority, without changing the device's Write Priority setting. Binary objects: 0 = inactive, 1 = active.

Both work on BACnet switch, number and climate entities:

action: bacnet.relinquish
target:
  entity_id: switch.ahu_1_supply_fan
data:
  priority: 8

Schedules (1.0.50 beta)

Beta: Schedule support is available in the 1.0.50 pre-releases. In HACS, enable Show beta versions for this integration to try it; the current stable release does not include it yet.

A BACnet Schedule object is imported as a sensor showing the value the schedule currently commands. The schedule itself is read and changed with two services that target that sensor:

Service	What it does
bacnet.read_schedule	Returns the schedule as response data: weekly_schedule, exception_schedule, calendars (the dates of calendars the exceptions refer to), schedule_default, effective_period, controlled_objects, value_type, priority_for_writing.
bacnet.write_schedule	Changes weekly_schedule, exception_schedule, schedule_default and/or effective_period, in the same shape read_schedule returns. Fields you leave out are not touched. The schedule is read back afterwards and the action fails if the device rejected the change or stored something different.

action: bacnet.write_schedule
target:
  entity_id: sensor.ddc_heating_schedule
data:
  weekly_schedule:
    monday:
      - { time: "06:30:00", value: 21.5 }
      - { time: "22:00:00", value: null }   # null = back to the default
  exception_schedule:
    - period: { date: "2026-12-25" }
      priority: 10
      time_values:
        - { time: "00:00:00", value: 16 }
response_variable: schedule

• Weekly schedule — only the weekdays you pass are changed (one write per day). Pass all seven days to send the week as a single write, which some devices require.
• Exception schedule — always replaces the complete list. To protect the controller, the action fails (and lists them) if that would remove exceptions the device currently has. Pass the full list including the ones to keep, or set allow_removal: true if removing them is what you want. A period is one of date, date_range (start/end), week_n_day (month, week_of_month, weekday) or calendar_reference (Calendar object instance).
• Dates — write "YYYY-MM-DD", or {year, month, day, weekday} where null means any. Dates are always returned in the second form, with raw BACnet numbers (month 13/14 = odd/even months, day 32 = last day of the month, weekday 1 = Monday).
• Values are written in the schedule's own datatype (value_type).

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Examples

Complete automations for common tasks. Replace the entity IDs with your own. The examples use the automation syntax of Home Assistant 2024.10 and newer.

Occupancy override from a calendar

Command an area to occupied while a calendar event runs, and release the command when it ends so the controller's own schedule takes over again. The occupancy object here is a Multi-State Output (a number entity); check its bacnet_state_text attribute for which value means occupied on your device.

alias: Meeting room occupied during calendar events
triggers:
  - trigger: calendar
    event: start
    entity_id: calendar.meeting_room
    id: start
  - trigger: calendar
    event: end
    entity_id: calendar.meeting_room
    id: end
actions:
  - choose:
      - conditions:
          - condition: trigger
            id: start
        sequence:
          - action: bacnet.write_value
            target:
              entity_id: number.meeting_room_occupancy
            data:
              value: 1        # occupied on this device
              priority: 11
    default:
      - action: bacnet.relinquish
        target:
          entity_id: number.meeting_room_occupancy
        data:
          priority: 11        # release the same priority you wrote at

Always relinquish at the priority you wrote at. Turning a switch off or writing 0 commands the object off; only bacnet.relinquish releases it.

Temporary setpoint with a climate entity

Set a comfort setpoint in the morning and hand control back to the controller in the evening. Turning a BACnet climate entity off relinquishes its setpoint.

alias: Office comfort setpoint on weekdays
triggers:
  - trigger: time
    at: "07:00:00"
    id: "on"
  - trigger: time
    at: "18:00:00"
    id: "off"
conditions:
  - condition: time
    weekday: [mon, tue, wed, thu, fri]
actions:
  - if:
      - condition: trigger
        id: "on"
    then:
      - action: climate.set_temperature
        target:
          entity_id: climate.office_setpoint
        data:
          temperature: 21.5
    else:
      - action: climate.set_hvac_mode
        target:
          entity_id: climate.office_setpoint
        data:
          hvac_mode: "off"

Get notified when a device stops responding

Entities become unavailable when their device doesn't answer. After 10 failed polls a message also appears in Settings → Repairs; this automation notifies you sooner.

alias: BACnet device offline
triggers:
  - trigger: state
    entity_id: sensor.ahu_1_supply_temperature
    to: unavailable
    for: "00:05:00"
actions:
  - action: notify.notify
    data:
      message: "AHU 1 is not responding to BACnet requests."

Calendar events as schedule exceptions (1.0.50 beta)

Instead of overriding the controller, add each calendar event to its Schedule object as an exception. The controller then knows about the event in advance, so features like optimal start can prepare the space. This automation adds the exception 12 hours before the event and removes it when the event ends.

alias: Calendar events as BACnet schedule exceptions
triggers:
  - trigger: calendar
    event: start
    entity_id: calendar.meeting_room
    offset: "-12:00:00"
    id: add
  - trigger: calendar
    event: end
    entity_id: calendar.meeting_room
    id: remove
actions:
  - action: bacnet.read_schedule
    target:
      entity_id: sensor.meeting_room_schedule
    response_variable: schedule
  - variables:
      event_start: "{{ trigger.calendar_event.start }}"
      event_end: "{{ trigger.calendar_event.end }}"
      current: "{{ schedule['sensor.meeting_room_schedule'].exception_schedule or [] }}"
  - if:
      - condition: trigger
        id: add
    then:
      - action: bacnet.write_schedule
        target:
          entity_id: sensor.meeting_room_schedule
        data:
          exception_schedule: >-
            {% set start = as_local(as_datetime(event_start)) %}
            {% set end = as_local(as_datetime(event_end)) %}
            {{ current + [{
                 'period': {'date': start.date().isoformat()},
                 'priority': 11,
                 'time_values': [
                   {'time': start.strftime('%H:%M:%S'), 'value': 1},
                   {'time': end.strftime('%H:%M:%S'), 'value': none}
                 ]
               }] }}
    else:
      - action: bacnet.write_schedule
        target:
          entity_id: sensor.meeting_room_schedule
        data:
          exception_schedule: >-
            {% set start = as_local(as_datetime(event_start)) %}
            {% set ns = namespace(keep=[]) %}
            {% for ex in current %}
              {% set d = ex.period.get('date') %}
              {% if not (d and ex.priority == 11 and d.year == start.year
                         and d.month == start.month and d.day == start.day) %}
                {% set ns.keep = ns.keep + [ex] %}
              {% endif %}
            {% endfor %}
            {{ ns.keep }}
          allow_removal: true

• value: 1 is the occupied value and must match the schedule's value_type; run bacnet.read_schedule once in Developer tools → Actions to see what your schedule uses.
• none at the end time hands control back to the weekly schedule.
• The removal step drops every priority-11 exception on the event's date. Use a priority that nothing else on the controller uses for exceptions.
• Events that run past midnight need a date_range period instead of a single date.

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Troubleshooting

Problem	Likely cause	Solution
"No devices found"	Device not running or on a different subnet	Verify the device is reachable on UDP 47808
"Cannot connect"	Port 47808 already in use	Stop other BACnet software or use a different port
Entities show "Unavailable"	Device went offline	Check the device (and Settings → Repairs) — entities recover automatically.
"The BACnet device rejected the write"	Wrong write priority, or object not writable	Check the log for the reason; enable the Write Priority entity or check bacnet_commandable
Want to release an override	Turn off commands inactive, it doesn't release	Use the bacnet.relinquish service
COV not working	Device doesn't support COV	This is normal — polling activates as fallback
Write has no effect	Object is not commandable	Check the bacnet_commandable attribute
Values don't update	COV increment too high, or polling interval too long	Lower the COV increment or reduce the polling interval
Entities go unavailable after network blip	Expected — the integration detects outages and reconnects automatically. Entities recover once the device is reachable again.	No action needed
Write has no effect at expected priority	Device requires a specific priority level	Enable the Write Priority entity and select the correct level

Debug logging

Add this to your configuration.yaml for detailed BACnet logs:

logger:
  logs:
    custom_components.bacnet: debug

Diagnostics download

When reporting a problem, attach the diagnostics file: Settings → Devices & Services → BACnet IP → ⋮ → Download diagnostics. Network addresses are redacted.

Advanced tuning

The defaults suit most controllers. For unusual devices they can be changed in custom_components/bacnet/const.py:

Constant	Default	Meaning
RPM_MAX_OBJECTS	25	Objects per ReadPropertyMultiple poll request (halved automatically when the device rejects a request as too large)
MAX_CONCURRENT_REQUESTS	4	Parallel requests per device when individual reads are needed
METADATA_PERSIST_DELAY	5 s	Metadata changes found within this window cause one reload together

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Requirements

• Home Assistant 2024.4.0 or newer
• Python 3.12+
• Network UDP port 47808 accessible between HA and BACnet devices
• Cross-subnet A BBMD or BACnet router if devices are on a different network

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Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/my-improvement)
3. Submit a Pull Request

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License

GPL-3.0 — see LICENSE for details.

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