ComfoSpot for Home Assistant

A local, cloud-free Home Assistant integration for Zehnder ComfoSpot 55 decentralised ventilation units behind a ComfoControl gateway.

It speaks the gateway's local Flake protocol directly over your LAN — no cloud, no app account, no MQTT broker, no extra daemon. Fan control and sensor readings show up as native Home Assistant entities, set up entirely through the UI.

Important

Unofficial / unaffiliated. This project is not made, supported, or endorsed by Zehnder or getair. "ComfoSpot", "ComfoControl", and "Zehnder" are trademarks of their respective owners and are used here only to describe compatibility. The protocol was reconstructed by clean-room observation of local network traffic for the sole purpose of interoperability. Use at your own risk.

Contents

• Features
• Requirements
• Installation
• Configuration
• Entities
• How it works
• Limitations
• Troubleshooting
• Contributing
• License

Features

• 🌀 Fan control per zone — on/off and stages 1–4
• 🎯 Target temperature as a number entity (15–30 °C)
• 🌡️ Temperature and 💧 humidity per zone
• 🫁 Air quality index (Bosch BSEC IAQ, 0–500, lower is better)
• 🌤️ Barometric pressure (hPa)
• 🔍 Auto-discovery of the gateway via UDP broadcast
• 🏠 100 % local — local_polling, no cloud dependency, no credentials

Requirements

• A Zehnder ComfoSpot 55 system with a ComfoControl gateway on your LAN
• The gateway reachable from your Home Assistant host on the same subnet (discovery uses a UDP broadcast)
• Home Assistant 2024.1 or newer

Installation

HACS (recommended)

1. In HACS → ⋮ → Custom repositories, add https://github.com/Runje/comfospot-homeassistant with category Integration (or use the button above).
2. Install ComfoSpot, then restart Home Assistant.
3. Go to Settings → Devices & Services → Add Integration → ComfoSpot.

Manual

Copy custom_components/comfospot into your Home Assistant config/custom_components/ directory and restart Home Assistant.

Configuration

Everything is configured from the UI — there is nothing to add to configuration.yaml. On first add, the integration tries to auto-discover the gateway via UDP broadcast and pre-fills its IP address; otherwise enter the gateway's IP manually. No username or password is required (the local protocol is unauthenticated).

Entities

Entity	Type	Notes
fan.<zone>	Fan	On/off + stages 1–4
number.<zone>_target_temperature	Number	15–30 °C
sensor.<zone>_temperature	Sensor	Indoor temperature
sensor.<zone>_humidity	Sensor	Indoor relative humidity
sensor.comfospot_air_quality_index	Sensor	Bosch BSEC IAQ, 0–500, lower is better
sensor.comfospot_air_pressure	Sensor	Barometric pressure in hPa
sensor.comfospot_operating_hours	Sensor	Diagnostic
sensor.comfospot_air_quality_sensor_status	Sensor	Diagnostic — BSEC calibration state

The gateway carries a BME680-style environmental sensor; its properties mirror the vendor app's humidity / pressure / temperature / airQualityIndex / airQualityIndexAccuracy domain model. In versions before 0.1.8 the pressure reading was mislabelled as CO₂ and the IAQ index was exposed as "Unknown 0x1043"; existing entities are migrated automatically (history is kept, but Home Assistant may warn once about the changed unit of the former CO₂ sensor).

The gateway is added as a hub device, and each ventilation zone appears as a sub-device linked to it.

How it works

The ComfoControl gateway answers a UDP broadcast on port 9987 and then accepts a plaintext TCP control connection on port 9986 speaking the Flake object-sync protocol. This integration reimplements that connection/transport layer (dynamic tokens + ACKs) and the property model, discovers the ventilation zone(s), and maps them to Home Assistant entities.

In a ComfoSpot Twin setup the three physical units act as a single coordinated zone — alternating supply/exhaust airflow for heat recovery — so they are presented as one fan.

Limitations

• Per-fan values are not exposed. The gateway publishes only aggregated, per-zone values over the network. Individual fan readings live in the internal Bluetooth-mesh layer, which is not reachable over the LAN protocol.
• UDP must reach the gateway. The gateway only opens its TCP control port after receiving a UDP discovery packet, so Home Assistant and the gateway should be able to exchange UDP broadcasts (same subnet recommended).

Troubleshooting

• "Failed to connect" when adding the integration — confirm the gateway IP, make sure Home Assistant is on the same subnet, and that no firewall/VLAN blocks UDP 9987 or TCP 9986.

• Entities show "unavailable" after a while — this usually means the gateway stopped pushing updates; the integration re-subscribes on each poll to keep them alive. If it persists, reload the integration and open an issue with your Home Assistant logs (enable debug logging below).

• Enable debug logging:

  logger:
    default: info
    logs:
      custom_components.comfospot: debug

Contributing

Issues and pull requests are welcome! Please do not include any decompiled vendor code or copyrighted firmware in contributions — this project is a clean-room reimplementation and must stay that way. If you have a different ComfoSpot model or a multi-zone setup, reports about what works are especially helpful.

License

MIT © Thomas König