ComfoAir ESPHome Component

This project provides a robust integration for Zehnder ComfoAir (350, 450, 550) heat recovery ventilation (HRV) units into ESPHome.

Installation

Add the following to your ESPHome YAML configuration:

external_components:
  - source:
      type: git
      url: https://github.com/nyxnyx/esphome-comfoair
    components: [comfoair]

uart:
  id: uart_bus
  baud_rate: 9600
  tx_pin: TX  # Adjust for your board
  rx_pin: RX  # Adjust for your board

comfoair:
  id: my_comfoair
  name: "ComfoAir"
  uart_id: uart_bus
  # Add sensors/switches from the list below:

Available Features

Below is a complete list of all supported properties you can add under the comfoair: component.

Core Fan Sensors

Key	Type	Description	Unit
fan_supply_percentage	Sensor	Current supply fan power (%)	%
fan_exhaust_percentage	Sensor	Current exhaust fan power (%)	%
fan_speed_supply	Sensor	Rotational speed of supply fan	rpm
fan_speed_exhaust	Sensor	Rotational speed of exhaust fan	rpm

Temperature Sensors

Key	Type	Description	Unit
outside_air_temperature	Sensor	Fresh air entering from outside (T1)	°C
supply_air_temperature	Sensor	Fresh air entering the house (T2)	°C
return_air_temperature	Sensor	Warm air leaving the rooms (T3)	°C
exhaust_air_temperature	Sensor	Used air leaving to outside (T4)	°C
enthalpy_temperature	Sensor	Enthalpy sensor value (if present)	°C
ewt_temperature	Sensor	Ground heat exchanger value (if present)	°C

Status & Binary Sensors

Key	Type	Description
is_bypass_valve_open	Binary	State of the heat recovery bypass
is_preheating	Binary	Internal pre-heater status
is_summer_mode	Binary	Unit is in summer bypass mode
is_supply_fan_active	Binary	Status of the supply fan
is_filter_full	Binary	Indicates if filter maintenance is required

Operating Hours (Counters)

Key	Unit	Description
fan_hours_supply	h	Total runtime of supply fan
fan_hours_exhaust	h	Total runtime of exhaust fan
bypass_hours	h	Total hours bypass was open
preheater_hours	h	Total hours pre-heater was active
filter_hours	h	Hours since last filter change
ewt_hours	h	Ground heat exchanger runtime

Automation & Control

Key	Type	Description
auto_balance	Switch	Intelligent Speed Boost: Automatically adjusts fan speed (0-3) based on thermal efficiency. See details below.
error_code	Sensor	Last reported error code for diagnostics.

Feature: Auto Temperature Balance

The auto_balance feature (Thermal Power Guidance) intelligently adjusts the fan speed to reach your comfort temperature faster while minimizing energy loss.

Requirements

To use this feature, you must have the following sensors enabled in your comfoair: configuration:

• supply_air_temperature
• return_air_temperature
• auto_balance (the switch)
• is_preheating (optional, but recommended for energy saving)

How it works

1. Activate the Switch: Turn on the "Auto Temperature Balance" switch in Home Assistant.
2. Set Target Temperature: Choose your desired comfort temperature (e.g., 21°C) in your Climate card.

Automation Logic:

• Helping Mode: If the unit provides air that moves the house towards the target (e.g., 18°C supply when you want 21°C cooling), it will boost the fans (up to Stage 3).
• Protective Mode: If the outside air is counter-productive (e.g., 30°C supply when you want 21°C cooling), it will reduce speed to Stage 0 (Absent) to preserve the indoor climate.
• Safety: If is_preheating is active, the system throttles speed to avoid excessive heating costs.

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Service Functions

Reset Filter Timer

You can reset the filter maintenance timer directly from ESPHome using a template button:

button:
  - platform: template
    name: "Reset Filter Timer"
    on_press:
      then:
        - lambda: |-
            id(my_comfoair)->reset_filter();

Visualization

For a premium look in Lovelace, we recommend using the Simple Thermostat Card or lovelace-comfoair.

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Maintained by @nyxnyx. Forked from @wichers.