Carbon monoxide cleared

The Carbon monoxide cleared condition passes when one or more carbon monoxide sensors are no longer detecting carbon monoxide (CO). After a CO event, you want to be absolutely sure the air is safe before letting your automation silence the alarm or tell the household everything is fine.

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. Select what you want to check. Under By target (see Targets), pick the area your CO sensor is in (like your kitchen or garage). You can also select a floor, a device, a specific entity, or a label.
5. From the conditions shown for that target, select Carbon monoxide cleared.
6. Under Condition passes if (see Behavior), pick Any or All to control how the check behaves when multiple sensors are targeted.
7. 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 air_quality.is_co_cleared. A basic example looks like this:

condition: air_quality.is_co_cleared
target:
  entity_id: binary_sensor.hallway_co

This passes when the hallway carbon monoxide sensor is no longer detecting CO.

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 air_quality entity behind that target.

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

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

• Sensors that are unavailable (unavailable) or have an unknown state (unknown) do not count as cleared. With Any behavior, they are skipped. With All behavior, the condition fails if every targeted sensor is unavailable.
• To check whether carbon monoxide is currently detected, use Carbon monoxide detected.
• To check the actual CO concentration, use Carbon monoxide value.

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 silence the alarm once every CO sensor has cleared

After a CO event, you want the alarm to keep sounding until every room is safe. This automation triggers when you press the silence button, but the condition requires every CO sensor in the house to read clear before the siren actually turns off. If any sensor still detects carbon monoxide, the alarm keeps going.

• Trigger: State: Silence alarm button pressed
• Condition: Air Quality: Carbon monoxide cleared
• Target: All CO sensors (hallway, basement)
• Condition passes if: All
• Action: Siren: Turn off, then notify the household

alias: "Silence alarm only after full CO all-clear"
triggers:
  - trigger: state
    entity_id: input_button.silence_alarm
conditions:
  - condition: air_quality.is_co_cleared
    target:
      entity_id:
        - binary_sensor.hallway_co
        - binary_sensor.basement_co
    options:
      behavior: all
actions:
  - action: siren.turn_off
    target:
      entity_id: siren.house_alarm
  - action: notify.mobile_app_phone
    data:
      title: "CO all-clear"
      message: >
        Every CO sensor reads clear.
        The alarm has been silenced.

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:

• Carbon monoxide detected - Tests if one or more carbon monoxide sensors are detecting carbon monoxide.

• Carbon monoxide value - Tests the carbon monoxide level of one or more entities.