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ESPHome Climate Component for Mitsubishi Heatpumps using direct serial connection


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Wirelessly control your Mitsubishi Comfort HVAC equipment with an ESP8266 or ESP32 using the ESPHome framework.


  • Instant feedback of command changes via RF Remote to HomeAssistant or MQTT.
  • Direct control without the remote.
  • Uses the SwiCago/HeatPump Arduino libary to talk to the unit directly via the internal CN105 connector.


Supported Microcontrollers

This library should work on most ESP8266 or ESP32 platforms. It has been tested with the following MCUs:

  • Generic ESP-01S board (ESP8266)
  • WeMos D1 Mini (ESP8266)
  • Generic ESP32 Dev Kit (ESP32)

Supported Mitsubishi Climate Units

The underlying HeatPump library works with a number of Mitsubishi HVAC units. Basically, if the unit has a CN105 header on the main board, it should work with this library. The HeatPump wiki has a more exhaustive list.

The same CN105 connector is used by the Mitsubishi KumoCloud remotes, which have a compatibility list available.

The whole integration with this libary and the underlying HeatPump has been tested by the author on the following units:

  • MSZ-GL06NA
  • MFZ-KA09NA


Step 1: Build a control circuit.

Build a control circuit with your MCU as detailed in the SwiCago/HeatPump README. You can use either an ESP8266 or an ESP32 for this.

Note: several users have reported that they've been able to get away with not using the pull-up resistors, and just directly connecting a Wemos D1 mini to the control board via CN105.

Step 2: Use ESPHome 1.18.0 or higher

The code in this repository makes use of a number of features in the 1.18.0 version of ESPHome, including various Fan modes and external components.

Step 3: Add this repository as an external component

Add this repository to your ESPHome config:

  - source: github://geoffdavis/esphome-mitsubishiheatpump

Step 3a: Upgrading from 1.x releases

Version 2.0 and greater of this libary use the ESPHome external_components feature, which is a huge step forward in terms of usability. In order to make things compile correctly, you will need to:

  1. Remove the libraries section that imports, as this is handled by the external_component section of manifest.
  2. Remove the includes section that imports src/esphome-mitsubishiheatpump
  3. Delete the old checkout of this repository under src/esphome-mitsubishiheatpump.
  4. Clean your old ESPHome build directories out (3-dot menu, "Clean Build Files")
  5. You may also have to delete the esphomenodename directory that corresponds with your esphomenodename.yaml configuration file completely. This directory may exist in your base config directory, or in config/.esphome/build. Testing with ESPHome 0.18.x showed this to be necessary to get the cached copy of src/esphome-mitsubishiheatpump to go away entirely, as the "Clean Build Files" isn't as thorough as one would like.

Note: Failure to delete the old source directory and remove the includes and libraries lines will likely result in compilation errors complaining about duplicate declarations of MitsubishiHeatPump::traits().

Example error
Linking /data/bedroom_east_heatpump/.pioenvs/bedroom_east_heatpump/firmware.elf
/root/.platformio/packages/toolchain-xtensa/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/bin/ld: /data/bedroom_east_heatpump/.pioenvs/bedroom_east_heatpump/src/esphome/components/mitsubishi_heatpump/espmhp.cpp.o: in function `MitsubishiHeatPump::traits()':
espmhp.cpp:(.text._ZN18MitsubishiHeatPump6traitsEv+0x4): multiple definition of `MitsubishiHeatPump::traits()'; /data/bedroom_east_heatpump/.pioenvs/bedroom_east_heatpump/src/esphome-mitsubishiheatpump/espmhp.cpp.o:espmhp.cpp:(.text._ZN18MitsubishiHeatPump6traitsEv+0x80): first defined here

Step 4: Configure the heatpump

Add a mitsubishi_heatpump to your ESPHome config:

  - platform: mitsubishi_heatpump
    name: "My Heat Pump"

    # Optional
    hardware_uart: UART0

    # Optional
    update_interval: 500ms

On ESP8266 you'll need to disable logging to serial because it conflicts with the heatpump UART:

  baud_rate: 0

On ESP32 you can change hardware_uart to UART1 or UART2 and keep logging enabled on the main serial port.

Note: this component DOES NOT use the ESPHome uart component, as it requires direct access to a hardware UART via the Arduino HardwareSerial class. The Mitsubishi Heatpump units use an atypical serial port setting ("even parity"). Parity bit support is not implemented in any of the existing software serial libraries, including the one in ESPHome. There's currently no way to guarantee access to a hardware UART nor retrieve the HardwareSerial handle from the uart component within the ESPHome framework.

Example configuration

Below is an example configuration which will include wireless strength indicators and permit over the air updates. You'll need to create a secrets.yaml file inside of your esphome directory with entries for the various items prefixed with !secret.

  name: hptest
  friendly_name: Test Heatpump

  name: ${name}
  platform: ESP8266
  board: esp01_1m
  # Boards tested: ESP-01S (ESP8266), Wemos D1 Mini (ESP8266); ESP32 Wifi-DevKit2

  ssid: !secret wifi_ssid
  password: !secret wifi_password

  # Enable fallback hotspot (captive portal) in case wifi connection fails
    ssid: "${friendly_name} Fallback Hotspot"
    password: !secret fallback_password

# Note: if upgrading from 1.x releases of esphome-mitsubishiheatpump, be sure
# to remove any old entries from the `libraries` and `includes` section.
  # Remove reference to SwiCago/HeatPump

  # Remove reference to src/esphome-mitsubishiheatpump


# Enable logging
  # ESP8266 only - disable serial port logging, as the HeatPump component
  # needs the sole hardware UART on the ESP8266
  baud_rate: 0

# Enable Home Assistant API


# Enable Web server.
  port: 80

  # Sync time with Home Assistant.
  - platform: homeassistant
    id: homeassistant_time

# Text sensors with general information.
  # Expose ESPHome version as sensor.
  - platform: version
    name: ${name} ESPHome Version
  # Expose WiFi information as sensors.
  - platform: wifi_info
      name: ${name} IP
      name: ${name} SSID
      name: ${name} BSSID

# Sensors with general information.
  # Uptime sensor.
  - platform: uptime
    name: ${name} Uptime

  # WiFi Signal sensor.
  - platform: wifi_signal
    name: ${name} WiFi Signal
    update_interval: 60s

  - source: github://geoffdavis/esphome-mitsubishiheatpump

  - platform: mitsubishi_heatpump
    name: "${friendly_name}"

    # ESP32 only - change UART0 to UART1 or UART2 and remove the
    # logging:baud_rate above to allow the built-in UART0 to function for
    # logging.
    hardware_uart: UART0

Advanced configuration

Some models of heat pump require different baud rates or don't support all possible modes of operation. You can configure mulitple climate "traits" in YAML to match what your hardware supports. For example:

  - platform: mitsubishi_heatpump
    name: "My heat pump"
    hardware_uart: UART2
    baud_rate: 9600
      fan_mode: [AUTO, LOW, MEDIUM, HIGH]
      swing_mode: [OFF, VERTICAL]
      min_temperature: 16
      max_temperature: 31
      temperature_step: 1.0

Configuration variables that affect this library directly

  • hardware_uart (Optional): the hardware UART instance to use for communcation with the heatpump. On ESP8266, only UART0 is usable. On ESP32, UART0, UART1, and UART2 are all valid choices. Default: UART0
  • baud_rate (Optional): Serial BAUD rate used to communicate with the HeatPump. Most systems use the default value of 4800 baud, but some use 9600. Default: 4800
  • update_interval (Optional, range: 0ms to 9000ms): How often this component polls the heatpump hardware, in milliseconds. Maximum usable value is 9 seconds due to underlying issues with the HeatPump library. Default: 500ms
  • supports (Optional): Supported features for the device. ** mode (Optional, list): Supported climate modes for the HeatPump. Default: ['HEAT_COOL', 'COOL', 'HEAT', 'DRY', 'FAN_ONLY'] ** fan_mode (Optional, list): Supported fan speeds for the HeatPump. Default: ['AUTO', 'DIFFUSE', 'LOW', 'MEDIUM', 'MIDDLE', 'HIGH'] ** swing_mode (Optional, list): Supported fan swing modes. Most Mitsubishi units only support the default. Default: ['OFF', 'VERTICAL']

Other configuration

  • id (Optional): used to identify multiple instances, e.g. "denheatpump"
  • name (Required): The name of the climate component, e.g. "Den Heatpump"
  • visual (Optional): The core Climate component has several visual options that can be set. See the Climate Component documentation for details.

Remote temperature

It is possible to use an external temperature sensor to tell the heat pump what the room temperature is, rather than relying on its internal temperature sensor. You can do this by calling set_remote_temperature(float temp) on the mitsubishi_heatpump object in a lambda. Note that you can call set_remote_temperature(0) to switch back to the internal temperature sensor.

There are several ways you could make use of this functionality. One is to use a sensor automation:

  - platform: mitsubishi_heatpump
    name: "Lounge heat pump"
    id: hp

  # You could use a Bluetooth temperature sensor
  - platform: atc_mithermometer
    mac_address: "XX:XX:XX:XX:XX:XX"
      name: "Lounge temperature"
          - lambda: 'id(hp).set_remote_temperature(x);'

  # Or you could use a HomeAssistant sensor
  - platform: homeassistant
    name: "Temperature Sensor From Home Assistant"
    entity_id: sensor.temperature_sensor
        - lambda: 'id(hp).set_remote_temperature(x);'

Alternatively you could define a service that HomeAssistant can call:

    - service: set_remote_temperature
        temperature: float
        - lambda: 'id(hp).set_remote_temperature(temperature);'

    - service: use_internal_temperature
        - lambda: 'id(hp).set_remote_temperature(0);'

See Also

Other Implementations

The gysmo38/mitsubishi2MQTT Arduino sketch also uses the SwiCago/HeatPump library, and works with MQTT directly. The author of this implementation found mitsubishi2MQTT's WiFi stack to not be particularly robust, but the controls worked fine. Like this ESPHome repository, mitsubishi2MQTT will automatically register the device in your HomeAssistant instance if you have HA configured to do so.

There's also the built-in to ESPHome Mitsubishi climate component. The big drawback with the built-in component is that it uses Infrared Remote commands to talk to the Heat Pump. By contrast, the approach used by this repository and it's underlying HeatPump library allows bi-directional communication with the Mitsubishi system, and can detect when someone changes the settings via an IR remote.

Reference documentation

The author referred to the following documentation repeatedly: