2026.10.4
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Light level is not detected

The Light level is not detected condition passes when one or more light binary sensors are currently dark. Use it to gate an automation on a dark area, like only running a wake-up routine if the bedroom is still dark, or only turning on hallway lights when an outdoor sensor reports no daylight.

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 level is not detected.
  5. Under Targets (see Targets), select one or more light sensors, devices, an area, a floor, or a label.
  6. If you selected more than one target, under Condition passes if, pick Any or All.
  7. Under For at least, you can set how long the sensors must remain dark before the condition passes.
  8. Select Save.

Options in the UI

Condition passes if

When multiple light sensors are targeted, controls how results combine. Pick Any to pass if at least one targeted sensor is dark, or All to pass only when every sensor is dark.
For at least

How long the sensor or sensors must remain dark before the condition passes. The default is 0 (passes immediately).

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. For how an automation is built in YAML, refer to Automations in YAML.

In YAML, put the settings that are specific to this condition under options. Keep target, if the condition uses one, and general settings such as alias and enabled at the top level, next to condition.

In YAML, refer to this condition as illuminance.is_not_detected. A basic example looks like this:

ConditionConditions check whether something is true at that moment, for example, whether a door is closed. You can use them in automations and scripts. If a condition is not met, the actions that come after it in the same sequence do not run. At the top level of an automation or script, this stops the automation or script. [Learn more] 
condition: illuminance.is_not_detected
target:
  entity_id: binary_sensor.outdoor_light_sensor

This passes when the outdoor light sensor is currently dark.

Options in YAML

behavior string (Optional, default: any)

When multiple light sensors are targeted, controls how results combine:

  • any (default): passes if at least one targeted sensor is dark.
  • all: passes only when every targeted sensor is dark.
for string | integer | map (Optional, default: 00:00:00)

How long the sensor or sensors must remain dark before the condition passes. Accepts a duration string in HH:MM:SS format. For a list of all accepted formats, refer to Durations in automations and scripts.

Targets of the condition

This condition requires a target. The target is the object that Home Assistant will check. You can point the condition 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 will evaluate every matching light sensor behind that target.

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

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

To learn which entities Home Assistant includes for a device, area, floor, or label, and how it handles several entities, refer to Automation targets.

Behavior with multiple targets

When you target more than one entity (or select an area, floor, or label that contains several), the Condition passes if option controls how the results combine:

  • Any (default): the condition passes if at least one of the targeted entities matches. For example, if you check three smoke sensors and only one of them detects smoke, the condition still passes. This is useful for questions like “is there smoke anywhere in the house?”
  • All: the condition passes only when every targeted entity matches. For example, if you check the same three smoke sensors, the condition passes only once all three report cleared. This is useful for “is the entire house safe now?” checks, so your automation does not send an all-clear while one room still has a reading.

Good to know

  • The target must be a binary sensor with the light device class.
  • The sensor’s threshold for what counts as “no light detected” is set on the device itself.
  • Sensors that are unavailable or unknown are skipped. With Any, the condition passes if at least one of the other targeted sensors matches. With All, it passes if all the other targeted sensors match. If all targeted sensors are unavailable or unknown, All passes and Any fails.
  • For numeric illuminance readings (in lux), use Illuminance instead.
  • To check for the opposite state, use Light level is detected.

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. In the visual editor, select the UI options listed in the example or paste the YAML code.

Tip

You don’t need to edit YAML to use these examples. Copy a YAML snippet from this page, open the visual automation editor in Home Assistant, and press Ctrl+V (or Cmd+V on Mac). Home Assistant automatically converts the pasted YAML into the visual editor format, whether it’s a full automation, a single trigger, a condition, or an action.

Automation: only turn on hallway lights when motion is detected and it’s dark

When motion is detected in the hallway, only turn on the hallway light if the outdoor light sensor has been dark for at least 5 minutes.

  • Trigger: Motion detected (hallway sensor)
  • Condition: Light level is not detected
    • Target: Outdoor light sensor
    • For at least: 00:05:00
  • Action: Turn on light
    • Target: light.hallway
YAML example for motion-activated lights at night
AutomationAutomations in Home Assistant allow you to automatically respond to things that happen in and around your home. [Learn more] 
alias: "Turn on hallway light when dark and motion"
triggers:
  - trigger: motion.detected
    target:
      entity_id: binary_sensor.hallway_motion
conditions:
  - condition: illuminance.is_not_detected
    target:
      entity_id: binary_sensor.outdoor_light_sensor
    options:
      for: "00:05:00"
actions:
  - action: light.turn_on
    target:
      entity_id: light.hallway

Still stuck?

To find out why the condition didn’t pass, check it live in the automation editor, and look at the trace of the run. For details, refer to Testing automations. For common problems and their solutions, refer to Troubleshooting automations.

If that doesn’t help, 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.

Tip

AI assistants like ChatGPT or Claude can also explain conditions or suggest the right one when you describe what you want in plain language.

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