How to limit value of sensor using an template

Configuration
1

Hi everyone,
we just got some new power meters from our local electricity provider. These can be read out using some ir-reades. Unfortuantly, the jumping once or twice a day to totally unreasonable numbers. Therefore I wanted to limit these jumps in order to gain meaningful charts and numbers in HA.

I’m currently using this template:

 - trigger:
      - platform: state
        entity_id: sensor.energiezaehler_kanzlei_pos_wirk_tariflos
        not_to:
          - unknown
          - unavailable
    sensor:
      - name: Stromverbrauch Kanzlei
        unique_id: stromverbrauch_kanzlei_2
        device_class: energy
        unit_of_measurement: kWh
        state_class: total_increasing
        state: >
          {% set x = trigger.to_state.state | float(0) %}
          {{x if (x > this.state) | float(0) and (x - this.state|float(0)) < 0.5 else this.state}}

But unfortunately this set’s the new “filtered” entity to “unavailable” instead of to the right value.

If it works, it should ignore all values that have a greater difference than 0.5 to the old value.

Has anyone an idea, why this doesn’t work?

Thanks in advance for your help!
Lars

2 
        state: >
          {% set new = trigger.to_state.state | float(0) %}
          {% set old = this.state | float(0) %}
          {{ new if new > old and new - old < 0.5 else old }}