Notify HomeMatic when a window is open.

window-open-notify-homematic.yaml

blueprint:
  name: Window Open, Notify HomeMatic CCU
  description:
    An automation blueprint that reduces the set temperature of your climate
    device or group if a window sensor is open for more than the preset wait time.
    It uses the Homematic window sensor channel to set the temperature to the "Open-window
    temperature" set in the device configuration. You should set the "Mode for temperature
    fall detection" to Inactive to avoid conflicts. It waits until the window is closed
    again in order to restore the climate entity temperature. It has an optional blocking
    entity to prevent the automation running unnecessarily, for example during the
    Summer season.

  domain: automation

  input:
    window_entity:
      name: Window Sensor
      description: The window sensor that will control the climate entity.
      selector:
        entity:
          domain: binary_sensor
          device_class: window

    open_delay:
      name: Windows Open Wait Time
      description: Time to delay after window opens before notifying HomeMatic.
      default: 30
      selector:
        number:
          min: 0.0
          max: 600.0
          unit_of_measurement: seconds
          mode: slider
          step: 1.0

    blocking_entity:
      name: (OPTIONAL) Blocking Entity
      description: If this entity's state is on, it will prevent the automation from running. E.g. summer mode or away mode.
      default:
      selector:
        entity:
          domain: input_boolean

    climate_entity:
      name: Climate Device
      description: The climate entity that is controlled by the window sensor.
      selector:
        entity:
          domain: climate

  source_url: https://gist.github.com/sotatech/500b53ee64ca5ad5299c22cde47407ed

variables:
  blocking_entity: !input blocking_entity
  climate_target: !input climate_entity
  climate_id: '{{ state_attr( climate_target, "id") }}'
  open_delay: !input open_delay

trigger:
  - platform: state
    entity_id: !input "window_entity"
    to: "on"
    for: !input "open_delay"

condition:
  - condition: template
    value_template: "{{ (blocking_entity == none) or (states[blocking_entity].state == 'off') }}"

action:
  - service: homematic.set_device_value
    data:
      address: "{{ climate_id }}"
      channel: 1
      param: "WINDOW_STATE"
      value: 1

  - wait_for_trigger:
      - platform: state
        entity_id: !input "window_entity"
        to: "off"
    continue_on_timeout: false

  - service: homematic.set_device_value
    data:
      address: "{{ climate_id }}"
      channel: 1
      param: "WINDOW_STATE"
      value: 0

mode: restart
max_exceeded: silent

Added blocking entity option. I use this with a summer_heating_mode helper to stop the automation running during the summer when it's not needed. Hopefully thus saving on batteries.