Energy dashboard: price unit label should dynamically adapt to the sensor's unit of measurement (e.g. EUR/L instead of EUR/m³)

[roblomq]

Summary

When configuring water consumption in the Energy dashboard, the price unit label always shows EUR/m³, even when the selected sensor measures in liters (L). The label does not adapt dynamically to the unit of measurement of the selected sensor.

Steps to reproduce

1. Create a template sensor that measures water consumption in liters (L), using an existing m³ sensor multiplied by 1000.
2. Go to Settings → Energy → Water and configure the new L-sensor as the water source.
3. Set a fixed price under "Use a fixed price".
4. Observe that the price field still shows EUR/m³ as the unit label, regardless of the sensor's actual unit.

Expected behavior

The price unit label should dynamically reflect the unit of measurement of the selected sensor. For example:

• If the sensor measures in m³, the label should show EUR/m³.
• If the sensor measures in L, the label should show EUR/L.
• Ideally, HA would also handle the conversion automatically, similar to how it was partially addressed for electricity in PR Fix incorrect unit displayed in energy grid flow settings #27822.

Why this matters

This creates a confusing user experience: users who switch to a liters-based sensor have to manually divide their price per m³ by 1000, and the label still shows EUR/m³, making it unclear whether the entered value is per m³ or per L. This can easily lead to incorrect cost calculations.

Related

• Issue Confusing unit hint for price calculation in Energy dashboard #26443 (Confusing unit hint for price calculation in Energy dashboard — addressed for electricity, not for water)
• PR Fix incorrect unit displayed in energy grid flow settings #27822 (Fix incorrect unit displayed in energy grid flow settings)

[karwosts]

I believe the label is correct because m3 really is expected, regardless of the unit of the source sensor. To change that would be a core issue with a real behavioral change, not simply a frontend issue with a label. Note electric is the same here, as it is labelled CUR/kWh, even for a MWh sensor. Gas is actually different because it doesn't support conversions.

Simply changing the behavior would probably be a breaking change, but maybe one could add a unit selector there to go with the number textbox, so user can enter the price in a unit of their choice.

If you want a different behavior here, probably best to request at https://github.com/orgs/home-assistant/discussions