Control a Mitsubishi mini-split with Google Home

Connect a CN105 ESP32 controller to the service port inside the Mitsubishi indoor unit, flash the firmware, and add the heat pump from the Google Home app. It appears as a thermostat for temperature, mode, voice commands, and routines. No Mitsubishi Wi-Fi adapter, Kumo Cloud account, Home Assistant server, or Serin Labs subscription is required.

Already have a controller? Set it up with Google Home.

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What Google Home can control

Google Home displays a standard thermostat. Fan speed, vane position, diagnostics, and other controls that are not available in Google's thermostat card remain accessible through the controller's built-in web interface.

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What you need

• A compatible Mitsubishi indoor unit: check the model number before ordering. One controller is needed for each indoor unit you want to control.
• A CN105 ESP32 controller: buy the pre-assembled controller, or use a supported board and cable from the DIY parts list.
• A USB-C data cable and supported browser: the initial flash runs in Chrome, Edge, or Brave on a computer.
• A compatible Google or Nest hub: Google Home needs a supported hub device to set up and control this Wi-Fi accessory. Check Google's current setup and compatibility guidance rather than relying on an old model table.
• IPv6 on the home network: the firmware depends on IPv6. Confirm it is enabled before troubleshooting the controller.

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Set up your controller

Setup has three parts: install the Matter-compatible firmware, connect the controller to the indoor unit, and add the thermostat in Google Home. The app transfers your Wi-Fi credentials over Bluetooth; there is no separate setup-hotspot step for initial pairing.

Follow the Google Home setup guide for prerequisites, pairing, and a final check that the indoor unit responds.

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Limits to understand before buying

• Beta firmware: it is newer and less tested than the ESPHome and Apple Home firmware.
• Not certified: Google Home displays a one-time uncertified-accessory warning. The product does not carry a Works with Google Home badge.
• Features not available in Google Home: dry mode, fan-only mode, fan speed, and vane direction are not reliably shown in the Google Home thermostat card.
• Diagnostics are available in the web interface: compressor frequency, outdoor temperature, runtime, and error codes do not appear in Google Home.
• One occupied CN105 port: the controller cannot share CN105 with a factory Wi-Fi adapter or wired wall controller.

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Google Home firmware or ESPHome through Home Assistant?

Use the firmware when Google Home is the main interface and you do not already run Home Assistant. Use ESPHome when you want the full mini-split feature set in Home Assistant and are comfortable exposing a thermostat from Home Assistant to Google Home. The Google Home card is similar either way; the difference is how much control remains available behind it.

For the deeper comparison—including the factory Kumo Cloud route—read how to add a Mitsubishi mini-split to Google Home.