blueprints/humidity-controlled-fan.yaml

blueprint:
  name: Humidity Controlled Fan with Hysteresis
  description: >
    Controls fans based on humidity sensor readings with hysteresis to prevent flip-flopping
    and safety mechanisms to prevent runaway operation. Supports multiple fans and the Zooz ZSE11
    humidity sensor or any compatible humidity sensor.
  domain: automation
  input:
    fans:
      name: Fan Entities
      description: One or more fans to control based on humidity
      selector:
        entity:
          domain: fan
          multiple: true

    humidity_sensor:
      name: Humidity Sensor
      description: Humidity sensor entity (e.g., Zooz ZSE11 or compatible sensor)
      selector:
        entity:
          domain: sensor
          device_class: humidity

    humidity_threshold:
      name: Humidity Threshold (%)
      description: Base humidity percentage threshold
      default: 60
      selector:
        number:
          min: 30
          max: 90
          unit_of_measurement: "%"

    hysteresis_high:
      name: High Hysteresis (%)
      description: Amount above threshold to turn fans ON (prevents rapid cycling)
      default: 5
      selector:
        number:
          min: 1
          max: 15
          unit_of_measurement: "%"

    hysteresis_low:
      name: Low Hysteresis (%)
      description: Amount below threshold to turn fans OFF (prevents rapid cycling)
      default: 3
      selector:
        number:
          min: 1
          max: 15
          unit_of_measurement: "%"

    turn_on_delay:
      name: Turn On Delay
      description: Delay before turning fans on (avoids brief humidity spikes)
      default: 30
      selector:
        number:
          min: 0
          max: 300
          unit_of_measurement: seconds

    max_runtime_minutes:
      name: Maximum Runtime (minutes)
      description: Maximum time fans can run continuously before forced shutdown
      default: 120
      selector:
        number:
          min: 15
          max: 480
          unit_of_measurement: minutes

    cooldown_minutes:
      name: Cooldown Period (minutes)
      description: Minimum time between fan cycles to prevent runaway operation
      default: 10
      selector:
        number:
          min: 2
          max: 60
          unit_of_measurement: minutes

mode: restart

trigger:
  - platform: state
    entity_id: !input humidity_sensor
    attribute: 
  - platform: state
    entity_id: !input humidity_sensor

variables:
  fans_entities: !input fans
  humidity_sensor: !input humidity_sensor
  base_threshold: !input humidity_threshold
  high_hysteresis: !input hysteresis_high
  low_hysteresis: !input hysteresis_low
  turn_on_threshold: "{{ base_threshold + high_hysteresis }}"
  turn_off_threshold: "{{ base_threshold - low_hysteresis }}"
  current_humidity: "{{ states(humidity_sensor) | float(0) }}"
  any_fan_on: >
    {{ expand(fans_entities) | selectattr('state', 'eq', 'on') | list | length > 0 }}
  max_runtime_seconds: "{{ (max_runtime_minutes | int) * 60 }}"

action:
  - choose:
      # Turn fans ON when humidity exceeds upper threshold
      - conditions:
          - condition: template
            value_template: >
              {{ current_humidity > turn_on_threshold }}
          - condition: template
            value_template: >
              {{ not any_fan_on }}
          - condition: template
            value_template: >
              {{ states(humidity_sensor) not in ['unavailable', 'unknown'] }}
        sequence:
          - delay:
              seconds: !input turn_on_delay
          # Re-check humidity after delay
          - condition: template
            value_template: >
              {{ states(humidity_sensor) | float(0) > turn_on_threshold }}
          - condition: template
            value_template: >
              {{ states(humidity_sensor) not in ['unavailable', 'unknown'] }}
          - service: fan.turn_on
            target:
              entity_id: "{{ fans_entities }}"
          # Set up automatic shutoff timer for runaway prevention
          - delay:
              seconds: "{{ max_runtime_seconds }}"
          - condition: template
            value_template: >
              {{ expand(fans_entities) | selectattr('state', 'eq', 'on') | list | length > 0 }}
          - service: fan.turn_off
            target:
              entity_id: "{{ fans_entities }}"
          # Enforce cooldown period
          - delay:
              minutes: !input cooldown_minutes

      # Turn fans OFF when humidity drops below lower threshold
      - conditions:
          - condition: template
            value_template: >
              {{ current_humidity < turn_off_threshold }}
          - condition: template
            value_template: >
              {{ any_fan_on }}
          - condition: template
            value_template: >
              {{ states(humidity_sensor) not in ['unavailable', 'unknown'] }}
        sequence:
          - service: fan.turn_off
            target:
              entity_id: "{{ fans_entities }}"
          # Enforce cooldown period
          - delay:
              minutes: !input cooldown_minutes