Power crossed threshold

The Power crossed threshold trigger fires when a power reading crosses into or out of a threshold zone that you define. You can detect when a reading moves above a level, drops below a level, enters a range, or leaves a range.

Use Power crossed threshold when the crossing moment matters, such as when an appliance starts drawing noticeable power, when a washing machine finishes, or when a circuit load moves into a range that needs attention.

When you target more than one entity, the trigger’s Trigger when option controls when it fires.

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 Power crossed threshold 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 power sensor is in. You can also select a device, a specific entity, or a label.
5. From the triggers shown for that target, select Power crossed threshold.
6. Under Threshold type, configure the zone the reading must cross for the trigger to fire:
   • Select Above or Below and enter a value to fire when the reading crosses that level.
   • Select In range and enter a lower and upper bound to fire when the reading enters the range from outside.
   • Select Outside range and enter a lower and upper bound to fire when the reading leaves the range.
   • For each option, you can enter a fixed power value, pick a sensor or number entity, or pick a user-created number helper as the threshold.
7. Under Trigger when (see Behavior), choose how multiple targeted sensors should behave. The default is Each.
8. Under For at least, set how long the reading must stay past the threshold before the trigger fires. Leave it at zero to fire immediately.
9. 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, Power crossed threshold is referred to as power.crossed_threshold. A basic example looks like this:

trigger: power.crossed_threshold
target:
  entity_id: sensor.washing_machine_power
options:
  threshold:
    type: below
    value:
      number: 3
      unit_of_measurement: "W"

This fires whenever the washing machine power reading crosses below 3 W.

To fire when a reading leaves a normal operating range:

trigger: power.crossed_threshold
target:
  entity_id: sensor.main_power
options:
  threshold:
    type: outside
    value_min:
      number: 500
      unit_of_measurement: "W"
    value_max:
      number: 3500
      unit_of_measurement: "W"

This fires whenever the main power reading crosses outside the 500 W to 3500 W range.

To use a user-created helperA helper is a virtual entity you create inside Home Assistant. It is not backed by a physical device. Helpers store values, track state, or do calculations that your automations and dashboards need. [Learn more] as a dynamic threshold that you can adjust without editing the automation:

trigger: power.crossed_threshold
target:
  entity_id: sensor.ev_charger_power
options:
  threshold:
    type: above
    value:
      entity: input_number.high_power_alert_threshold
  behavior: first

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 power entity behind that target.

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

• Use Power crossed threshold when you care about the moment a reading crosses a level or range boundary. If you want to react to every matching reading change instead, use Power changed.
• Supported thresholds can use fixed values, a sensor with the power device class, a number entity with the power device class, or a user-created helperA helper is a virtual entity you create inside Home Assistant. It is not backed by a physical device. Helpers store values, track state, or do calculations that your automations and dashboards need. [Learn more] from the Input number integration.
• Supported power units are mW, W, kW, MW, GW, TW, and BTU/h.
• If a targeted entity is unknown or unavailable, it cannot contribute to the trigger until it reports a valid power value again.
• This trigger works with sensors that have the power device class.

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: notify when the washing machine finishes

When the washing machine power crosses below 3 W and stays there for 5 minutes, send a notification so you know the cycle is done.

• Trigger: Power crossed threshold
  • Target: Washing machine power sensor
  • Threshold type: Below 3 W
  • For at least: 00:05:00
• Action: Send a notification message
  • Target: My Device (notify.my_device)

alias: "Notify when the washing machine finishes"
triggers:
  - trigger: power.crossed_threshold
    target:
      entity_id: sensor.washing_machine_power
    options:
      threshold:
        type: below
        value:
          number: 3
          unit_of_measurement: "W"
      for: "00:05:00"
actions:
  - action: notify.send_message
    target:
      entity_id: notify.my_device
    data:
      message: "The washing machine cycle is finished."

Automation: turn on a warning light when a heater starts drawing high power

When a space heater power reading crosses above 1500 W, turn on a warning light so the load is easy to notice.

• Trigger: Power crossed threshold
  • Target: Space heater power sensor
  • Threshold type: Above 1500 W
• Action: Turn on light
  • Target: light.high_load_warning

alias: "Turn on warning light when heater power gets high"
triggers:
  - trigger: power.crossed_threshold
    target:
      entity_id: sensor.space_heater_power
    options:
      threshold:
        type: above
        value:
          number: 1500
          unit_of_measurement: "W"
actions:
  - action: light.turn_on
    target:
      entity_id: light.high_load_warning

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:

• Power changed: Triggers after one or more power values change.