Gas detected

The Gas detected condition passes when one or more gas sensors are actively detecting gas. Gas sensors watch for combustible or toxic gases in the air, helping protect your home from leaks and hazardous buildups. Add this condition to your automation so it only takes action while a gas hazard is still present, for example keeping the kitchen exhaust fan running for as long as the sensor reports gas, or making sure an emergency notification goes out only when the threat is real and ongoing.

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 gas 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 Gas detected.
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_gas_detected. A basic example looks like this:

condition: air_quality.is_gas_detected
target:
  entity_id: binary_sensor.kitchen_gas

This passes when the kitchen gas sensor is currently detecting gas.

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 detecting. With Any behavior, they are skipped. With All behavior, the condition fails if every targeted sensor is unavailable.
• To check whether gas is no longer detected, use Gas cleared.

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: alert when you arrive home and gas is detected

If a gas leak started while you were away, you want to know the moment you pull into the driveway. This automation triggers when you arrive home and checks whether the kitchen gas sensor is still detecting gas. If it is, you get an urgent notification before you even open the front door so you know to stay outside and call for help.

• Trigger: Zone: Person enters home zone
• Condition: Air Quality: Gas detected
• Target: Kitchen gas sensor
• Condition passes if: Any
• Action: Notify: Send urgent notification

alias: "Gas alert on arrival home"
triggers:
  - trigger: zone
    entity_id: person.frenck
    zone: zone.home
    event: enter
conditions:
  - condition: air_quality.is_gas_detected
    target:
      entity_id: binary_sensor.kitchen_gas
    options:
      behavior: any
actions:
  - action: notify.mobile_app_phone
    data:
      title: "Gas detected at home"
      message: >
        The kitchen gas sensor is detecting gas.
        Do not enter the house.

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:

• Gas cleared - Tests if one or more gas sensors are cleared.