How to retrieve data from a Statistics sensor?

Configuration
1

I have successfully created a statistics sensor for some temperature data. However I now want to display the max & min values so I used a template to extract the relevant data. But it’s not working. This is what I’ve got:

  - platform: statistics
    name: "Greenhouse Stats"
    entity_id: sensor.greenhouse_temperature
    sampling_size: 10000
    max_age:
      minutes: 1440

  - platform: template
    sensors:
      greenhouse_temp_max:
        value_template: "{{ state_attr('sensor.greenhouse_stats_mean', 'max_value') }}"
      greenhouse_temp_min:
        value_template: "{{ state_attr('sensor.greenhouse_stats_mean', 'min_value') }}"

However both greenhouse_temp_min and greenhouse_temp_max are saying “Unknown” despite having values when I examine the “Greenhouse Stats” entity. There’s no errors/warnings in the logs concerning these entities.

I’m sure there’s some simple config error here I’m not seeing.

2

Your sensor name is set to

name: "Greenhouse Stats"

So the entity id should be

sensor.greenhouse_stats

but you are trying to extract data from a sensor named

sensor.greenhouse_stats_mean
3

According to the documentation for Statistics “It exports the mean value as state and the following values as attributes”.

The answers to other questions on here say that there is a _mean suffix:

But I assure you I have tried it without the _mean suffix as well and it didn’t work.

4

I am trying to replicate your issue but for me it works.

Have a look:
Here’s my yaml entry:

- platform: statistics
  name: "Home Temp Stats"
  entity_id: sensor.home_temperature
  sampling_size: 10000
  max_age:
      minutes: 1440

Here’s the created sensor

mean
mean1086×126 3.89 KB

Note that there is no

_mean

in the entity_id.

And here’s the output from the template

mean2
mean2977×279 19.1 KB

You can test the template output using the developer-tools.

Also in your config, try to define the type of your sensor

  - platform: template
    sensors:
      greenhouse_temp_max:
        unit_of_measurement: '°C'
        value_template: |
              {{ state_attr('sensor.greenhouse_stats', 'max_value') | float }}
5

OK, so I cut it down to just one section in the template and it works without the _mean. So added the second one, and now that works as well. I have no idea why it didn’t work before.

I’m happy that it’s working properly, and thank you for your interest. But it’s frustrating that I followed what I could find in the manual and on the forum without any luck. Presumably something has changed in the last few years.

6

It used to create sensor.object_id_mean as the sensor entity id. It was changed to drop the _mean a few releases ago but the state is still the mean value. So if you saw an example somewhere it could be out of date.

7

in addition to what Tom said, ALWAYS check the entity exists when you see these types of errors. Dev tools will show the correct entity name for you