Light brightness

The Light brightness condition passes when a light 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]‘s brightness meets a threshold you set. Use it to gate an automation based on how bright the light currently is, not just whether it’s on or off.

When you target more than one light, the condition’s behavior option controls how the check combines. You can require any targeted light’s brightness to match, or demand that all of them do.

Using this condition from the user interface

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

To use this condition in an automation:

1. Go to Settings > Automations & scenes.
2. Open an existing automation, or select Create automation > Create new automation.
3. In the And if section, select Add condition.
4. From the search box, search for and select Light: Light brightness.
5. Under Targets, select the light entity, an area, a floor, or a label.
6. Under Threshold type, set the brightness percentage the condition checks against.
7. Under Condition passes if, pick Any or All.
8. Select Save.

Options in the UI

Using this condition 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, refer to this condition as light.is_brightness. A basic example looks like this:

condition: light.is_brightness
target:
  entity_id: light.living_room
options:
  threshold: 50
  behavior: any

This passes when the living room light’s brightness is at or above 50%.

Options in YAML

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

Targets

This condition supports targets. A target tells Home Assistant what the condition should check. You can point it at 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, and Home Assistant evaluates every matching light entity behind that target.

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

You can also mix target types in one condition. For example, combine a specific entity with an area to check both at once.

Good to know

• A light that is off has brightness zero, so it never meets a positive threshold. Combine with Light is on if you want to check both.
• Lights that are unavailable (unavailable) or have an unknown state (unknown) are skipped for Any and fail for All.
• Pair with Light brightness crossed threshold as a matching trigger when you need the automation to run the moment the brightness crosses that line.

Try it yourself

Ready to test this? Go to Settings > Automations & scenes, open an automation, and add this condition. Trigger the automation with and without the condition met, and watch whether it continues or stops.

More examples

Real scenarios where this condition gates an automation. Copy any example and adapt it to your setup.

Automation: only start the movie scene if the room is dim enough

When the movie-night button is pressed, only start the movie scene if the living room light is dimmer than 40%. If the room is still bright, prompt for manual dimming first.

• Trigger: State: Movie night button pressed
• Condition: Light brightness
• Target: Living room light
• Threshold type: 40
• Condition passes if: Any
• Action: Scene: Movie night

alias: "Movie scene only if dim"
triggers:
  - trigger: state
    entity_id: input_button.movie_night
conditions:
  - condition: light.is_brightness
    target:
      entity_id: light.living_room
    options:
      threshold: 40
      behavior: any
actions:
  - action: scene.turn_on
    target:
      entity_id: scene.movie_night

Still stuck?

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

Related conditions

These conditions work well alongside this one:

• Light is on - Tests if one or more lights are on.

• Light is off - Tests if one or more lights are off.