Monitor and control your Atrea RD5 ventilation unit from Home Assistant using Modbus TCP.
- 🌡️ 5 temperature sensors: outdoor air (T-ODA), supply air (T-SUP), extract air (T-ETA), exhaust air (T-EHA), indoor air (T-IDA)
- 🔄 Ventilation mode: tracks current mode (Off / Automatic / Ventilation / Circulation / Night cooling / ...)
- 💨 Ventilation power: current requested fan power (0–100%)
- 🌐 BMS temperature source selects: choose between internal sensor or BMS-supplied value for T-ODA and T-IDA
- 📡 BMS setpoint write: push outdoor / indoor temperature values from HA automations to the HVAC
- 🍂 Heating season control: view the active season (Heating / Non-heating), configure the switching mode (TS / NTS / T-TODA / T-TODA+), and set the temperature threshold
- Efficient batch Modbus reads — consecutive registers are merged into a single Modbus request per poll cycle
- Zero-YAML setup via Home Assistant UI config flow
- Configurable poll interval (5–300 s) editable post-setup without re-adding the integration
- Home Assistant 2024.1.0 or newer
- Atrea RD5 unit with Modbus TCP enabled and accessible on the network (default port: 502)
- Python package
pymodbus >= 3.10.0(installed automatically by HA)
- Copy the
custom_components/atrea_rd5_modbus/folder into your Home Assistant config directory:<config>/custom_components/atrea_rd5_modbus/ - Restart Home Assistant.
- Go to Settings → Devices & Services → Add Integration.
- Search for Atrea RD5 Modbus and follow the setup wizard.
- In HACS, go to Integrations → ⋮ → Custom repositories.
- Add
https://github.com/thozza/homeassistant-atrea-rd5-modbusas type Integration. - Click Download on the Atrea RD5 Modbus card.
- Restart Home Assistant.
- Go to Settings → Devices & Services → Add Integration and search for Atrea RD5 Modbus.
The integration is configured entirely through the UI. During setup you will be asked for:
| Field | Default | Description |
|---|---|---|
| Host | — | IP address of the Atrea RD5 device |
| Port | 502 |
Modbus TCP port |
| Unit ID | 1 |
Modbus unit ID |
| Scan interval | 30 |
Poll frequency in seconds |
The connection is validated before the entry is saved — if the device is unreachable an error is shown in the form.
| Entity | Unit | Description |
|---|---|---|
| T-ODA Outdoor Air | °C | Outdoor air temperature (sensor T-ODA) |
| T-SUP Supply Air | °C | Supply air temperature after heat recovery (sensor T-SUP) |
| T-ETA Extract Air | °C | Room exhaust air entering the unit (sensor T-ETA) |
| T-EHA Exhaust Air | °C | Air leaving the unit to the outside (sensor T-EHA) |
| T-IDA Indoor Air | °C | Indoor/room air temperature (sensor T-IDA) |
| Ventilation Power | % | Current requested ventilation fan power (0–100%) |
| Ventilation Mode | — | Current operation mode (Off, Automatic, Ventilation, Circulation, ...) |
| T-ODA Source | — | Select: choose outdoor temp source (Internal / BMS) |
| T-IDA Source | — | Select: choose indoor temp source (CP / T-ETA / TRKn / BMS) |
| BMS T-ODA Setpoint | °C | BMS-supplied outdoor temp (write-only, −50–130 °C) |
| BMS T-IDA Setpoint | °C | BMS-supplied indoor temp (write-only, −50–130 °C) |
| Heating Season | — | Current season state (Heating / Non-heating) — diagnostic |
| Season Switch Mode | — | Select: season switching logic (TS / NTS / T-TODA / T-TODA+) |
| Season Temperature Threshold | °C | Outdoor temp threshold for automatic season switching (0–30 °C) |
The Atrea RD5 can use temperatures supplied by Home Assistant in place of its own outdoor (T-ODA) or indoor (T-IDA) sensors. This integration exposes the relevant device registers as four entities:
| Entity | Type | Purpose |
|---|---|---|
select.atrea_rd5_t_oda_source |
select | Choose internal sensor or BMS-supplied T-ODA |
select.atrea_rd5_t_ida_source |
select | Choose CP / T-ETA / TRKn / BMS for T-IDA |
number.atrea_rd5_bms_t_oda_setpoint |
number | T-ODA value pushed to the HVAC |
number.atrea_rd5_bms_t_ida_setpoint |
number | T-IDA value pushed to the HVAC |
The HVAC declares a temperature-sensor fault if a BMS-sourced value is not refreshed within 90 seconds. The integration writes to the device every time the number entity is set, but it does not run an internal periodic push — that's left to your automation. Keep your update cadence comfortably below 90 s (we recommend ≤60 s).
After a Home Assistant restart, each BMS setpoint number entity restores its last known value and immediately writes it back to the HVAC, so the watchdog window starts fresh before your automation's next trigger.
automation:
- alias: "Atrea: push outdoor temperature from weather sensor"
trigger:
- platform: time_pattern
seconds: "/30"
action:
- service: number.set_value
target:
entity_id: number.atrea_rd5_bms_t_oda_setpoint
data:
value: "{{ states('sensor.outdoor_temperature') | float }}"Pair this with select.atrea_rd5_t_oda_source set to BMS so the
HVAC actually consumes the supplied value.
The Atrea RD5 can switch between heating season (TS) and non-heating season (NTS) automatically or on demand. This integration exposes three entities for this feature:
| Entity | Type | Purpose |
|---|---|---|
sensor.atrea_rd5_heating_season |
sensor | Read-only diagnostic: current season (Heating / Non-heating) |
select.atrea_rd5_season_switch_mode |
select | Configure the switching mode: TS / NTS / T-TODA / T-TODA+ |
number.atrea_rd5_season_temperature_threshold |
number | Outdoor temp threshold used by the T-TODA / T-TODA+ modes (0–30 °C) |
Switching modes:
| Mode | Behaviour |
|---|---|
TS |
Force heating season |
NTS |
Force non-heating season |
T-TODA |
Auto: switch to NTS when T-ODA ≥ threshold |
T-TODA+ |
Auto with hysteresis: switch to NTS when T-ODA ≥ threshold, back to TS when T-ODA falls below it |
The polling interval (default 30 s) is editable post-setup via Configure on the integration tile in Settings → Devices & Services. Allowed range: 5–300 s.
The integration uses a single DataUpdateCoordinator (AtreaCoordinator) that owns a persistent AsyncModbusTcpClient TCP connection. On each poll cycle, registers are read in contiguous batches — consecutive same-type addresses are merged into a single Modbus request automatically. This minimises network round-trips and scales well as more sensors are added.
custom_components/atrea_rd5_modbus/
├── __init__.py # Integration setup, coordinator + client lifecycle
├── coordinator.py # DataUpdateCoordinator, batched Modbus reads
├── const.py # Register map, signed10() conversion, batch grouping
├── sensor.py # 8 read-only sensor entities (temperatures, power, mode, season)
├── select.py # 3 select entities (T-ODA / T-IDA source, season switch mode)
├── number.py # 3 number entities (BMS setpoints, season temp threshold)
└── config_flow.py # UI config flow with live connection validation
To add a new sensor in the future: add one entry to REGISTER_MAP in const.py and one entry to SENSOR_DESCRIPTIONS in sensor.py. Batch grouping is recomputed automatically.
Enable debug logging in configuration.yaml:
logger:
default: warning
logs:
custom_components.atrea_rd5_modbus: debugCommon issues:
- Cannot connect — verify the device IP, port (default 502), and that Modbus TCP is enabled on the unit
- Entities unavailable — check HA logs for Modbus errors; ensure the unit ID is correct (usually 1)
- Stale/missing values — increase the scan interval if the device reports protocol errors on rapid polling
This is an unofficial community integration. It is not sponsored by, affiliated with, or endorsed by ATREA s.r.o. in any way. Use it at your own risk.
Apache 2.0 — see LICENSE.