Home Assistant Aggregate Humidity Sensor

A Home Assistant custom integration that creates a virtual aggregate humidity sensor. It dynamically discovers all humidity sensors (matching sensor.*humidity*), tracks their current values, and exposes:

• A binary state (on if any humidity exceeds a configurable threshold, otherwise off)
• A persistent, user-changeable threshold (default: 70)
• A list of all humidity sensors and their current values
• A list of sensors currently over threshold (with values)

Includes:

• Example Lovelace dashboard panel (example/dashboard-panel.yaml)
• Automation blueprint for handling state changes (blueprints/automation/aggregate_humidity_sensor_state_change.yaml)

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Features

• Automatic discovery: Tracks all humidity sensors matching sensor.*humidity*
• Efficient: Polls on a configurable interval (default: 30s)
• User-configurable threshold: Adjustable via service call; persists across restarts
• Automation-friendly: Blueprint for reacting to state changes, with access to which sensors exceeded threshold

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Installation

Manual

1. Copy the custom_components/aggregate_humidity_sensor/ directory to your Home Assistant config/custom_components/ directory.
2. Restart Home Assistant.
3. Add to your configuration.yaml:

   sensor:
     - platform: aggregate_humidity_sensor

4. (Optional) Copy example/aggregate-dashboard-sensor.yaml into your Lovelace dashboard.

HACS (Recommended)

1. In Home Assistant, go to HACS > Integrations > Custom repositories.
2. Add this repo URL as a custom repository of type Integration.
3. Install the Humidity Panel integration from HACS.
4. Restart Home Assistant.
5. Add to configuration.yaml as above.

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Usage

• The integration creates a sensor called sensor.aggregate_humidity_sensor.
• The sensor’s state is "on" if any discovered humidity sensor is above the threshold, "off" otherwise.
• The following attributes are available:
  • matching_sensors: List of all matched humidity sensors (entity_ids)
  • sensor_values: Dictionary of entity_id → value (float)
  • over_threshold_sensors: Dictionary of entity_id → value for sensors currently over threshold
  • any_over_threshold: Boolean (same as sensor state)
  • threshold: The currently applied threshold

Changing the threshold

After some AI-assisted research, I recommend 70% RH as the point at which to concentrate effort on reducing humidity rather than raising temperature to remain warm. Above this level, damp reduces the effectiveness of clothing and heating and it is more cost-effective in domestic situations to spend resources on reducing humidity. You may want to choose a lower value, as that's better for long term health. Going below 40% is not recommended.

Call the service:

service: aggregate_humidity_sensor.set_threshold
data:
  threshold: 65  # Set your desired value

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Example Dashboard Panel

The example/dashboard-panel.yaml file provides:

• An auto-entities card showing all humidity sensors, sorted by value, using the sensor list discovered by the integration.
• A "Humidity" button that turns red if any sensor is over threshold.

To use:

1. Install auto-entities card and button-card via HACS.
2. Copy-paste the contents of example/dashboard-panel.yaml into your Lovelace dashboard (YAML mode or as a manual card).

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Automation Blueprint

Included at: blueprints/automation/aggregate_humidity_sensor_state_change.yaml

This blueprint triggers on any state change of sensor.aggregate_humidity_sensor and exposes the new and old state as variables in your actions. You can use this to, for example, start a timer to leave a dehumidifier running for an hour after humidity drops below threshold.

Example usage:

use_blueprint:
  path: pljones/aggregate_humidity_sensor/aggregate_humidity_sensor_state_change.yaml
  input:
    aggregate_humidity_sensor_sensor: sensor.aggregate_humidity_sensor
    actions:
      - choose:
          - conditions: "{{ new_state == 'off' and old_state == 'on' }}"
            sequence:
              - service: timer.start
                target:
                  entity_id: timer.dehumidifier_off
          - conditions: "{{ new_state == 'on' and old_state == 'off' }}"
            sequence:
              - service: switch.turn_on
                target:
                  entity_id: switch.dehumidifier

Use state_attr('sensor.aggregate_humidity_sensor', 'over_threshold_sensors') in your actions to get the dictionary of sensors currently over threshold.

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Development & Support

• This integration is custom and not affiliated with Home Assistant core.
• For issues or feature requests, please open an issue on GitHub.

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Copyright

Custom Aggregate Humidity Sensor Component -- Copyright (C) 2025 Peter L Jones

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.

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License

GNU Affero 3.0 - see LICENCE.md or https://www.gnu.org/licenses/agpl-3.0.html