Volatile organic compounds value

The Volatile organic compounds value condition passes when a VOC sensor’s reading meets a specific level. VOCs are invisible gases released by paints, cleaning supplies, new furniture, and even scented candles. You often notice them as that “new car” or “fresh paint” smell, and at higher concentrations they affect comfort and health. This condition lets your automation respond proportionally, turning on the ventilation fan only when VOC readings are genuinely elevated and leaving it off during a normal day so you save energy.

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 Volatile organic compounds value 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 VOC sensor is in (like your living room or bedroom). You can also select a device, a specific entity, or a label.
5. From the conditions shown for that target, select Volatile organic compounds value.
6. Under Threshold type, set the level the condition checks against:
   1. Pick whether the reading must be Above, Below, In range, or Outside range of the threshold.
   2. Select Number or Entity:
      • Number: Enter a fixed level directly, for example 300. For In range or Outside range, enter both a lower and upper bound.
      • Entity: Use a sensor entity or a number helper entity as the threshold:
        • Number helper: You can adjust the threshold value without editing the automation. The sensor reading is compared against the number helper’s current value.
        • Sensor: Its current reading becomes the threshold and updates automatically as the sensor changes.
        • For In range or Outside range, you need two entities: one for the lower bound and one for the upper bound (for example, two separate number helpers).
        • If you don’t have a number helper, you can create one by selecting Create a new number helper.
7. Under Unit, select the concentration unit (μg/m³ or mg/m³) to use for the threshold comparison.
8. Under Condition passes if (see Behavior), pick Any or All.
9. 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, 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 air_quality.is_voc_value. A basic example looks like this:

condition: air_quality.is_voc_value
target:
  entity_id: sensor.living_room_voc
options:
  threshold:
    type: above
    value:
      number: 300
      unit_of_measurement: "μg/m³"
  behavior: any

This passes when the living room VOC sensor reads above 300 μg/m³.

Options in YAML

threshold:
  type: between
  value_min:
    entity: input_number.voc_alert_level
  value_max:
    number: 500
    unit_of_measurement: "μg/m³"

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 volatile organic compounds sensor behind that target.

• Entity: one specific volatile organic compounds sensor, such as sensor.living_room_voc.
• Device: every volatile organic compounds sensor that belongs to a device.
• Area: every volatile organic compounds sensor in a room or area.
• Floor: every volatile organic compounds sensor on a floor.
• Label: every volatile organic compounds 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

• 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.
• Some sensors report VOCs as a ratio instead of an absolute concentration. For those sensors, use Volatile organic compounds ratio 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. In the visual editor, select the UI options listed in the example or paste the YAML code.

Automation: start the air purifier when you wake up only if VOC levels are high

Overnight, off-gassing from furniture, carpets, and cleaning products pushes VOC levels up in a closed room. This automation triggers at wake-up time and checks the living room VOC reading. If the level is above 300 μg/m³, the air purifier turns on to clear the air before you start your day. On mornings when the air is already fresh, the purifier stays off and you save energy.

• Trigger: Time: 07:00
• Condition: Volatile organic compounds value
  • Target: Living room VOC sensor
  • Threshold type: Above 300 μg/m³
• Action: Turn on fan
  • Target: Living room purifier

alias: "Morning purifier if VOCs are high"
triggers:
  - trigger: time
    at: "07:00:00"
conditions:
  - condition: air_quality.is_voc_value
    target:
      entity_id: sensor.living_room_voc
    options:
      threshold:
        type: above
        value:
          number: 300
          unit_of_measurement: "μg/m³"
actions:
  - action: fan.turn_on
    target:
      entity_id: fan.living_room_purifier

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

Explore related conditions:

• Volatile organic compounds ratio value: Tests the volatile organic compounds ratio of one or more entities.

• Carbon dioxide value: Tests the carbon dioxide level of one or more entities.