daikin-altherma-esp32

ESP-IDF firmware for ESP32-S3 boards that reads a Daikin Altherma heat pump through its X10A service port. View live readings in the local web UI and publish them to Home Assistant through MQTT. An optional HomeHub connection provides a separate read-only Modbus source.

Requirements

• A Daikin Altherma with an X10A header.
• A supported ESP32-S3 board with at least 8 MB flash.
• An X10A cable: JST-EH 2.5 mm, 5-pin connector, two signal wires and common ground.
• USB power and a browser supporting Web Serial for installation.

Setup

1. Choose your board and follow the safe wiring guide.
2. Install with the web installer.
3. Join daikin-altherma-esp32-setup, then enter your home WiFi at http://192.168.4.1.
4. Rejoin your home network and open http://daikin-altherma-esp32.local.
5. Set your board under Settings → ESP32 → Hardware and the wired RX/TX pins under Settings → Protocol. Set the broker under Settings → Connections → MQTT if needed.

The setup guide covers each step and how to check that it worked.

UI

View live values, operating states, local history and optional plant diagnostics; unestablished readings appear as —.

Documentation

Documentation index · Home Assistant · Report a bug · Contributing

Scope & credits

The firmware reads the heat pump; it does not control it. Keep the unauthenticated HTTP API on a trusted LAN (security model).

MIT. Protocol and value definitions derived from ESPAltherma (MIT); see third-party notices. No warranty; not affiliated with Daikin.