Homekit doesn't enable Air Quality by Luftdaten PM25 Sensor template

Configuration
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1

I would like to integrate my Air Quality Sensor into Homekit. I use Luftdaten PM25 sensor and prepared a HA template. The sensor works properly and is detected by homekit. Unfortunately it does not show any value or status. Does anyone know what’s wrong?

Bildschirmfoto 2020-04-17 um 00.07.13

Bildschirmfoto 2020-04-17 um 00.05.01

 - platform: statistics
    name: pm25 stats
    entity_id: sensor.luftdaten_p2
    max_age:
      minutes: 60

  - platform: template
    sensors:
      air_quality_pm25:
        friendly_name: 'Luftqualität'
        value_template: >
          {% if   states('sensor.pm25_stats_mean') | float <=  15 %}EXCELLENT
          {% elif states('sensor.pm25_stats_mean') | float <=  30 | float > 15 %}GOOD
          {% elif states('sensor.pm25_stats_mean') | float <=  55 | float > 30 %}FAIR
          {% elif states('sensor.pm25_stats_mean') | float <= 110 | float > 55 %}INFERIOR
          {% elif states('sensor.pm25_stats_mean') | float >  110 %}POOR
          {% endif %}