On Restart sensor restores previous value which messes up statistics

Configuration
1

I have a sensor which updates just before midnight to get the final reading cost of that days electricity. This sensor is then is fed into a Statistics (mean) sensor to give me an average cost based on the last weeks readings. My issue is that on a restart the first sensors value is restored which then upsets the Statistic calculation. Is there a way around this? Or is there a better way to do it?

  - trigger:
      - platform: time_pattern
        hours: 23
        minutes: 59
    sensor:
      - name: "Daily Energy Cost"
        unique_id: 'daily_energy_cost'
        icon: mdi:cash
        state: "{{ states('sensor.smart_meter_energy_cost_today')|float }}"
        unit_of_measurement: "GBP"

  - platform: statistics
    name: "Average Energy Cost"
    unique_id: average_energy_cost
    entity_id: sensor.daily_energy_cost
    state_characteristic: mean
    sampling_size: 7
2

Following.

I’m struggling with something similar, trying to use “sum” statistics to track cumulative rainfall last 7 days based on a template sensor that updates daily at 11:59pm based on a sensor that has yesterday’s rainfall. Unfortunately, restarting HA causes the sensor template to update, causing it to add yesterday’s rainfall to the total twice.

3

Can anybody explain how to use Statistics within Home assistant WITHOUT a restart affecting the results? Or even a workaround?

4

The only way I have managed to get this to work without any interuption from restarts is by using the HACS Average Sensor add on.

5

This didn’t work either! As far as I can see there is no way to use either the statistics or average platforms that are not affected by a home assistant restart. This surely should be simple to do!