[SOLVED] How to calculate average per day value for series of last year?


sorry, but I’m a bit stuck in getting the following implemented in a rule: I have a smart meter in my house of which I every day get the state at midnight and store it in a number item (so if I use 20kWh per day, then it’s for 5 days 20, 40, 60, 80, 100). With lastState and state I manage to calculate the daily delta of my energy consumption.

Yet, I would like to calculate the per day average over the last year but there I am stuck. Is there a way, to get the last 365 values of my daily delta item? These I would sum up then and divide by 365. But I have no idea, how to get those 365 values and sum them up in a variable.

If anybody could help, that would be very nice and thanks for any hint in advance.


Sorry for fooling around :sweat_smile:

But for real, how do you store your data? MySQL, InfluxDB yada yada.
Do you want to make this calculation multiple times a Day/Week/Year?

I would simply create a small Python3 script which gets the data calculates what I want, send it via. REST API to openHAB to a new “Yearly Energy Average item” which would be persisted again.

Or when using InfluxDB and Grafana just create a graph with what you want :slight_smile:

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You for got the “You must be lost” tag. :smiley:

This is a help forum for OpenHAB & smart Home, not general programming tips & tricks

I can see he is doing at least something with openHAB since he wrote he is stuck on a “rule” :smiley: (I hope)

Haha! Great joke! :rofl::joy::rofl:

But I figured something myself


which does the trick itself.

Thanks for the help!


Wait? Item.averageSince(now.minusDays(365))
Doesn’t that give you the value from 365 days ago?

What do you think the “averageSince” is trying to say?

Yep, misinterpreted that one :slight_smile:

That gives the average over the last year.
The title requested the average for EACH DAY over the past year which should yield 365 values. not 1.

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Sorry for my noobish questions.

In the context, I found this useful: https://www.element14.com/community/community/design-challenges/forget-me-not/blog/2014/08/29/ip-post-10-my-story-of-persistance-with-persistance-on-openhab