blueprints/hvac-failure-monitor.yaml

blueprint:
  name: HVAC Failure Monitor
  description: >
    Detects HVAC underperformance and hard failure by monitoring temperature trends when heating or cooling is active.
    Uses differential between setpoint and outdoor temp to dynamically adjust expectations.
  domain: automation
  input:
    thermostat:
      name: Thermostat
      description: The climate entity to monitor (must support hvac_action and setpoint attributes).
      selector:
        entity:
          domain: climate

    heating_temp_sensors:
      name: Heating Temperature Sensors
      description: One or more temperature sensors to monitor during heating (e.g. upstairs).
      default: []
      selector:
        target:
          entity:
            domain: sensor
            device_class: temperature

    cooling_temp_sensors:
      name: Cooling Temperature Sensors
      description: One or more temperature sensors to monitor during cooling (e.g. downstairs).
      default: []
      selector:
        target:
          entity:
            domain: sensor
            device_class: temperature

    outdoor_sensor:
      name: Outdoor Temperature Source
      description: Outdoor temperature source (e.g. from a weather entity).
      selector:
        entity:
          domain: weather

    monitoring_interval:
      name: Monitoring Interval (minutes)
      description: How long after HVAC starts to evaluate temperature change.
      default: 20
      selector:
        number:
          min: 5
          max: 120
          unit_of_measurement: minutes
          mode: slider

    notify_target:
      name: Notification Target
      description: Who to notify on potential HVAC failure (e.g. mobile app).
      default: []
      selector:
        target:
          entity:
            domain: notify

mode: single

trigger:
  - platform: state
    entity_id: !input thermostat
    attribute: hvac_action
    to:
      - heating
      - cooling

variables:
  thermostat: !input thermostat
  heating_temp_sensors: !input heating_temp_sensors
  cooling_temp_sensors: !input cooling_temp_sensors
  outdoor_sensor: !input outdoor_sensor
  interval: !input monitoring_interval
  hvac_action: "{{ state_attr(thermostat, 'hvac_action') }}"
  direction: >
    {{ 'rising' if hvac_action == 'heating' else 'falling' }}
  selected_sensors: >
    {{ heating_temp_sensors if hvac_action == 'heating' else cooling_temp_sensors }}

condition: []

action:
  - variables:
      indoor_start: >
        {{ expand(selected_sensors) | map(attribute='state') | map('float') | select('defined') | list | average }}

  - delay:
      minutes: "{{ interval }}"

  - variables:
      indoor_now: >
        {{ expand(selected_sensors) | map(attribute='state') | map('float') | select('defined') | list | average }}
      outdoor_now: >
        {{ state_attr(outdoor_sensor, 'temperature') | float }}
      setpoint: >
        {{ state_attr(thermostat, 'temperature') | float }}
      delta: >
        {{ (setpoint - outdoor_now) | abs }}
      required_rate: >
        {% set d = delta %}
        {{ [0.01, [0.10, 0.10 - (d * 0.004)] | min] | max }}
      observed_rate: >
        {{ ((indoor_now - indoor_start) / interval) | round(3) }}
      trend_ok: >
        {% if direction == 'rising' %}
          {{ observed_rate >= required_rate }}
        {% else %}
          {{ observed_rate <= -required_rate }}
        {% endif %}
      hard_failure: >
        {% if direction == 'rising' %}
          {{ observed_rate < 0 }}
        {% else %}
          {{ observed_rate > 0 }}
        {% endif %}
      hvac_state_icon: >
        {% if hard_failure %}
          mdi:close-circle-outline
        {% elif not trend_ok %}
          mdi:alert-circle-outline
        {% else %}
          mdi:check-circle-outline
        {% endif %}
      hvac_state_text: >
        {% if hard_failure %}
          HVAC Failure
        {% elif not trend_ok %}
          Possible HVAC underperformance
        {% else %}
          Normal operation
        {% endif %}

  - choose:
      - conditions: "{{ not trend_ok }}"
        sequence:
          - choose:
              - conditions: "{{ notify_target | length > 0 }}"
                sequence:
                  - service: notify.{{ notify_target }}
                    data:
                      message: >
                        HVAC '{{ hvac_action }}' action for {{ interval }} minutes showed ineffective operation.
                        Indoor temp started at: {{ indoor_start }}°, now: {{ indoor_now }}°
                        Outdoor temp: {{ outdoor_now }}°
                        Setpoint: {{ setpoint }}°
                        Required rate: {{ required_rate }}°/min
                        Observed rate: {{ observed_rate }}°/min
                        Status: {{ hvac_state_text }} {{ hvac_state_icon }}
            default:
              - service: persistent_notification.create
                data:
                  title: HVAC Alert
                  message: >
                    HVAC '{{ hvac_action }}' action for {{ interval }} minutes showed ineffective operation.
                    Indoor temp started at: {{ indoor_start }}°, now: {{ indoor_now }}°
                    Outdoor temp: {{ outdoor_now }}°
                    Setpoint: {{ setpoint }}°
                    Required rate: {{ required_rate }}°/min
                    Observed rate: {{ observed_rate }}°/min
                    Status: {{ hvac_state_text }} {{ hvac_state_icon }}