Handle nested devices in energy device consumption.

[karwosts]

I propose adding ability for an energy device to designate another device as its parent, to improve correctness of energy calculations.

Currently if you have a monitor on a circuit, and another monitor reported by a device plugged into that circuit, the device is double counted, leading to wrong graphs and wrong untracked consumption. By denoting the parent the sum could account for the childs reported device when summing them together.

This parent-child relationship would be considered when rendering energy graphs, to visually show child consumption as a subset of the parent, and not in-addition to the parent. (See frontend PR for exact graph details).

Related PRs (already implemented but asked to come here first):
home-assistant/core#132616
home-assistant/frontend#23185

[EnochPrime]

I like this idea. I don't have a physical parent device, but I use a sensor group to combine all my lighting energy monitors together and track that as a single item in the energy dashboard.

Have you considered alternatives to having a parent-child relationship? And if so how do they compare pro/cons vs the approach you are proposing?

Some ideas that come to mind are:

• automatically separating sensor groups added to the dashboard
• allow using a label to automatically pull in and combine separate sensors

[karwosts]

While there may be interesting things that could be done with groups in energy dashboard, I don't really see that as within the scope of this proposal.

This simply seeks to resolve the situation where user has two individual devices, and the consumption of one is included within the consumption of another, and therefore makes the strict sum of all devices incorrect due to double counting.