Humidifier turned on

The Humidifier turned on trigger fires after a humidifier entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more] turns on. Use it to start an automation the moment the device powers up, whether you turned it on manually, through the app, or via another automation.

When you target more than one humidifier, the Trigger when option controls when it fires. You can have it fire the first time any targeted humidifier turns on, only after all targeted humidifiers have turned on, or every single time any of them turn on.

Using this trigger from the user interface

If you prefer building automations visually, Home Assistant walks you through this trigger step by step. You pick what to watch, tweak a few options, and save. No YAML knowledge required.

To use Humidifier turned on in an automation:

1. Go to Settings > Automations & scenes.
2. Open an existing automation, or select Create automation > Create new automation.
3. In the When section, select Add trigger.
4. Select what you want to monitor. Under By target (see Targets), pick the area your humidifier is in (like your bedroom or living room). You can also select a device, a specific entity, or a label.
5. From the triggers shown for that target, select Humidifier turned on.
6. Under Trigger when (see Behavior), pick Each, First, or All to control how the trigger behaves when multiple humidifiers are targeted.
7. Under For at least, set how long the humidifier must stay on before the trigger fires. Leave it at zero to fire immediately.
8. Select Save.

Options in the UI

Using this trigger in YAML

If you work directly in YAML, or you want to know exactly what Home Assistant does under the hood, this section has the technical reference. It lists the field names you use in YAML, their types, and which ones are required.

In YAML, Humidifier turned on is referred to as humidifier.turned_on. A basic example looks like this:

trigger: humidifier.turned_on
target:
  entity_id: humidifier.bedroom

This fires every time humidifier.bedroom transitions from off to on.

Options in YAML

YAML sometimes provides additional options for more complex use cases that are not available through the UI.

Targets of the trigger

This trigger requires a target. The target is the object that Home Assistant will watch. You can select a single entityAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more], a device, an area, a floor, or a label as a target, and Home Assistant will watch every matching humidifier entity behind that target.

• Entity: one specific humidifier entity, such as humidifier.living_room.
• Device: every humidifier entity that belongs to a device.
• Area: every humidifier entity in a room or area.
• Floor: every humidifier entity on a floor.
• Label: every humidifier entity that shares a label.

You can also select different target types in one trigger. For example, you can add a specific entity and an area as targets in the same trigger to monitor both of them at once.

Behavior with multiple targets

When you target more than one entity (or select an area, floor, or label that contains several), the Trigger when option controls how the trigger responds:

• Each (any in YAML, default): the trigger fires every time any one of the targeted entities transitions. For example, if you monitor three motion sensors in the living room and someone walks past sensor 1, the automation fires. When they walk past sensor 2 a moment later, it fires again. Every individual event counts.
• First (first in YAML): the trigger fires only on the first transition in the targeted group, then waits until all targeted entities have reset before it fires again. For example, if you monitor the same three motion sensors, the automation fires when the first one picks up movement (someone entered the room). The other two firing afterward are ignored, so you get one notification per “someone walked in” event instead of three.
• All (last in YAML): the trigger fires only after the last targeted entity in the group has fired, meaning all of them are now in the expected state. For example, if you monitor the lights in the living room, bedroom, and hallway, the automation fires only once all three have turned off. This is useful for scenarios like “start the robot vacuum only after every light on the floor is off,” so you know the room is truly empty.

Good to know

• The trigger only fires when a humidifier transitions from a known, valid state. If a humidifier comes back from the Unavailable or Unknown state, the trigger does not fire for that recovery.
• Turning on a humidifier does not necessarily mean it starts actively humidifying immediately. To react when humidification actually begins, use Humidifier started humidifying instead.
• To react to the opposite transition, use Humidifier turned off.

Try it yourself

Ready to test this? Go to Settings > Automations & scenes, create a new automation, and add this trigger. Save the automation, then change the state of the targeted entity to watch the trigger fire on your actual entitiesAn entity represents a sensor, actor, or function in Home Assistant. Entities are used to monitor physical properties or to control other entities. An entity is usually part of a device or a service. [Learn more].

More examples

Real scenarios where this trigger fires in automations and scripts. Copy any example and adapt it to your setup.

Automation: turn on a fan when the bedroom humidifier powers on

When the bedroom humidifier turns on, start a low-speed fan to help distribute the moisture more evenly throughout the room.

• Trigger: Humidifier turned on
• Target: Bedroom humidifier
• Trigger when: Each
• For at least: 00:00:00
• Action: Fan: Turn on

alias: "Start fan when bedroom humidifier turns on"
triggers:
  - trigger: humidifier.turned_on
    target:
      entity_id: humidifier.bedroom
    options:
      behavior: any
      for: "00:00:00"
actions:
  - action: fan.turn_on
    target:
      entity_id: fan.bedroom
    data:
      percentage: 30

Automation: notify when the nursery humidifier turns on overnight

If the nursery humidifier turns on during the night, send a quiet notification to your phone so you know air quality is being maintained without having to check the app.

• Trigger: Humidifier turned on
• Target: Nursery humidifier
• Trigger when: Each
• Condition: Time is between 22:00 and 07:00
• Action: Send a mobile notification

alias: "Notify on nursery humidifier at night"
triggers:
  - trigger: humidifier.turned_on
    target:
      entity_id: humidifier.nursery
    options:
      behavior: any
      for: "00:00:00"
conditions:
  - condition: time
    after: "22:00:00"
    before: "07:00:00"
actions:
  - action: notify.mobile_app_phone
    data:
      message: "Nursery humidifier turned on."

Still stuck?

The Home Assistant community is quick to help: join Discord for real-time chat, post on the community forum with the trigger you’re using and what you expected to happen, or share on our subreddit /r/homeassistant.

Related triggers

These triggers work well alongside this one:

• Humidifier turned off: Triggers after one or more humidifiers turn off.

• Humidifier started humidifying: Triggers after one or more humidifiers start actively humidifying.

• Humidifier started drying: Triggers after one or more humidifiers start actively drying (dehumidifying).