Getting a single value from a device's state in Home Assistant

I recently acquired . Everything was very straightforward.

I noticed that each valve not only allows remote control but also offers a state with several attributes. I wanted to extract the room's temperature indicator from it. It was not as easy as I thought it was, so I want to describe how I managed to achieve it.

By default, the Netatmo valve displays a multi-valued state. To check, go to the Developer Tools > States menu. You can use a filter to find the device.

The problem is that the above attributes are not readily usable. We must first extract them individually. For this, we need to create a sensor; head to File Editor and select configuration.yaml. Then, append the following snippet:

template:

  - sensor:

    - unique_id: sensor.spare_bedroom_temperature

      name: "Spare Bedroom Temperature"

      state: "{{ state_attr('climate.spare_bedroom', 'current_temperature') }}" #1

      unit_of_measurement: "°C"

      device_class: temperature                                                 #2

1. Match the pair entity-attribute above


2. Must be temperature to be used as a temperature sensor afterward

Click on Save.

We don't need to restart Home Assistant, but we must reload the configuration. Click on Developer Tools. Then, click on Check configuration. The new sensor should appear in Settings > Entities.

At this point, whenever we add the Area card to a dashboard, Home Assistant displays our newly-created temperature sensor on top of it.

Originally published at A Java Geek on May 18^th, 2025