Migrating gas tracking in Energy Dashboard from Viessmann kWh sensors to a m³ meter (without losing history?)

gomble · April 1, 2026, 10:24am

Title: Migrating gas tracking in Energy Dashboard from Viessmann kWh sensors to a m³ meter (without losing history?)

Hi everyone,

I’m currently using Home Assistant’s Energy Dashboard to track gas consumption from my Viessmann heating system. At the moment I use two separate daily kWh sensors:

sensor.verbrauch_heizung_tag – daily gas usage for heating in kWh
sensor.verbrauch_warmwasser_tag – daily gas usage for domestic hot water in kWh

These are estimated values provided by the Viessmann controller, not measured at the gas meter itself.

I’m now adding a new sensor that reads directly from the gas meter in m³ (for example sensor.gas_meter_m3). This will be more accurate, because it’s taken directly from the physical meter instead of being calculated by the boiler.

What I’d like to achieve:

Keep the existing history of gas usage based on the two Viessmann kWh sensors (for the past months/years).
From now on, use only the new m³ meter sensor as the gas source in the Energy Dashboard.
Ideally have a continuous history: past data from the old kWh sensors, new data from the m³ sensor, without losing or “breaking” the old charts.

My questions to the community:

Is it possible to switch the gas source in the Energy Dashboard from
sensor.verbrauch_heizung_tag and sensor.verbrauch_warmwasser_tag
to a single sensor.gas_meter_m3 without losing the historical data of the two old sensors?
When I change the configured gas source in the Energy settings:
- Will the previous history remain visible (e.g. old days/months still show the kWh-based data, and new days show the m³-based data)?
- Or will the Energy Dashboard essentially start “fresh” with the new sensor and no longer show the previous history?
If it’s not possible to have a smooth migration, is there a recommended workaround, such as:
- Keeping the old kWh sensors only for history and adding a second gas source?
- Creating a template sensor that somehow combines or converts the historical kWh data and the new m³ sensor into a single entity?
- Any database-level or recorder-based tricks that are still safe and supported?

If someone has already done a similar migration (from Viessmann kWh estimates like sensor.verbrauch_heizung_tag and sensor.verbrauch_warmwasser_tag to a direct meter reading in m³), I’d really appreciate a step‑by‑step explanation of what you changed in the Energy Dashboard and what happened to your history afterwards.

Thanks a lot for any insights or best practices on how to handle this transition!