(Generic) Thermostat - Extra/Auxiliary heater with setpoint = master heater - 1°C

Configuration
1

I have a room services by a heater, but it is heating the place up too slowly.

I have a heat blower available that I want to add to assist it in heating. It makes some noise of course and I would like to use it only to heat up the room from a low temperature and switch it of when the temperature is the target_temperature for the room -1°C .

I use the “Generic thermostat” (separate zigbee thermometer and zigbee relay).

What is the best way to control the secondary heater - only one target temperature should be directly controled from a Scheduler or by manual override.

Possibilities:

  • Feed a temperature through a formula into another Generic Thermostat (for the auxiliary heater) - can I just do something like {{ sensor.other +1 }};
  • Fee a target temperature that is a copy the first one, again, is that just {{ climate. -1 }} ?
  • Use an integration that already does this?
2

I created a sensor and a “Programmable Thermostat” from the corresponding integration, but I haven’t determined yet how to track the on/off/heat/auto state.

# climate: !include climate.yaml        in configuration.yaml
- platform: programmable_thermostat
  name: 'Room Aux'
  heater:
   # This is not a light but a 16A relay that is classified as a light.
    - light.tz3000_5ng23zjs_ts0001_55471efe_on_off
  actual_temp_sensor: sensor.room_temperature_temperature
  target_temp_sensor: sensor.room_aux_temperature
  min_temp: 7
  max_temp: 23
  # hvac_options: 3   # The temperature does not seem to track in manual mode
  hvac_options: 5  # The temperature tracks in auto mode.
  auto_mode: heating
  min_cycle_duration:
     seconds: 60
  tolerance: 0.2
  initial_hvac_mode: 'off'

And the sensor is defined as

# sensor: !include sensors.yaml    in configuration.yaml
- platform: template
  sensors:
    room_aux_temperature:
      friendly_name: "°C Aux Room"
      value_template: "{{ state_attr('climate.room','temperature') - 1 }}"
      unit_of_measurement: "°C"
      device_class: temperature

So now this Programmable thermostat still needs to switch on and off along with the reference thermostat.
An extra difficulty is that the hvac_modes are different : the “Generic Thermostat” is using heating/off and the “Programmable thermostat” is using auto/off (in heating mode it does seem to track the temperature as this is considered “manual”).