Logically 'merge' devices

[ddeconin-gh]

Describe your core improvement

It should be possible for 2 devices (from different integrations) to be marked as the same device. An example could be a smart plug/power meter behind a wifi enabled washing machine. If HA knew this was the same logical 'device' , it could derive things like 'the power currently used by the washing machine...' etc.

Current limitations

This partially happens for MAC address enabled devices, but a lot of devices don't have a mac address....

Technical benefits

Makes more sense from a admin perspective to find all entities related to a 'logical device'.
Can be used for better automated dashboard building & as context for AI interactions.

Additional context

No response

[frenck]

It should be possible for 2 devices (from different integrations) to be marked as the same device

This is actually behavior we used to have and actually reverted / removed over the last year or so, as it caused more problems than it solved.

There are many edge cases you hit in doing this. Just an example, with devices that "later" (e.g., after enhancements on our end or the manufacturer end), turn out to be the same. Merge them? That turned out to be problematic, as there could be something already be in used by the end-user on each of those devices. The other way around happend often as well.

This is just one of the cases.

We do have other feature plans, which involve more of a display/UI handling instead of making them an actual same/merged device. But this is awaiting a major overhaul of what devices actually are in Home Assistant, which we hope to start with in Q1 of 2026 (but is a multi-year effort to complete).

../Frenck

[BBE-FR]

Hi.

Shouldn't this be considered again, in the period the naming tend to be modified to more use area / device / entity name instead of the friendly name ?

I think this could be a way to cover some corner cases (of course not all of them), to have a better device name, when two "HA devices" are related to the same physical device.
(power meter is a typical example).

Another possible use case:

• a temperature sensor, a door sensor and a power meter to monitor a fridge, there are 3 "HA devices" for the same "physical device".

If we could select a "parent device", or any other way to merge them, that would be great.

[mik-laj]

Currently, you can also add an entity from one device to another if you create a new template helper that will rely on data from another device but be attached to another one.

Here, for example, is the code that adds water level to a Xiaomi scale using the ESPHome-based scale.

[frenck]

Yes, but that is a helper; which is manual additions, not merge magic.

[mik-laj]

Yes, this isn't full automation, but it's a direction you can take to solve a problem. Later, you could write a script that would automatically copy one or more entities from one device to another based on the user's needs to solve the problem.

I think, the main problem is that you want the assistant to know how much electricity the washing machine is using when another device is measuring its consumption or building a dashboard easier and my solution solves this problem.

[ddeconin-gh]

My main reasoning for having a way to manually 'merge' devices logically together is

• Its already done for devices with the same MAC address
• It would provide context for use in automatic dashboard generation and AI use cases. If the AI knows the what power meter is attached to what house appliance, answering a question like 'how much power does my washing machine consume' would be easier to answer.

[spitfire]

Yes! I just connected a tuya-local device over Wi-Fi and it also shows up as a device from Unifi integration. I'd love to just have both merged into one, so I could just see all entities related to it at the same time

[squeaky-nose]

I've been using a HACS integration called PowerCalc. It creates (estimated) power entities for device. I like that it nicely adds the new sensors to the same device...

👆 ZHA integration, Ikea lamp WITH estimated power usage.👆

However i have another integration (Dynamic Energy Cost) that hooks into the energy sensor and creates a running cost component. Unfortunately this doesnt show up inside the same device. Ideally all 3 integrations should be viewable in the same device.

👆 Dynamic Energy Cost sensors. Would be nice to merge into Shelly EM sensor and Daikin AC integration.👆

Another usecase - merging a car charger with Dynamic Energy Cost integration

Sorry for using different examples (ZHA and AC). Hopefully illustrates that it makes sense to add this behaviour.

I think HA should forcefully group devices based on the integration. IE if multiple integrations are providing sensors - then they should show up in seperate cards (per integration).