Cost sensors

Powercalc can create cost sensors which track how much the consumed energy costs. A cost sensor multiplies the energy consumed by an energy price and accumulates the result over time. The created sensor has device class monetary and uses your Home Assistant currency as unit of measurement, so it can be used on dashboards and in the energy dashboard.

The energy price is configured globally, either as a fixed price or by pointing to a sensor which provides the current price per kWh (for example a dynamic tariff integration such as Nordpool, Tibber or Frank Energie).

Configuring the energy price

Define the price once in the global configuration. Provide either a fixed price or a price sensor.

Fixed price (per kWh, in your local currency):

powercalc:
  energy_price: 0.25

Price from an existing sensor:

powercalc:
  energy_price_sensor: sensor.current_energy_price

When both are set, the fixed price is ignored and the price sensor is used.

You can also add a fixed per-kWh surcharge to either price source. This is useful for taxes, grid fees, provider markup, or other usage-based charges that should be added to the base energy price:

powercalc:
  energy_price: 0.25
  energy_price_surcharge: 0.05

With this configuration, each consumed kWh is charged at 0.30 in your Home Assistant currency.

For percentage-based taxes or fees, use energy_price_multiplier. For example, use 1.21 to add 21% tax:

powercalc:
  energy_price: 0.25
  energy_price_surcharge: 0.05
  energy_price_multiplier: 1.21

The effective price is calculated as:

(energy_price or energy_price_sensor + energy_price_surcharge) * energy_price_multiplier

Enabling cost sensors

Similar to energy sensors and utility meters, cost sensor creation can be toggled globally and per powercalc sensor.

To create cost sensors for all powercalc sensors:

powercalc:
  energy_price: 0.25
  create_cost_sensors: true

To enable/disable per sensor (this overrides the global setting for that sensor):

sensor:
  - platform: powercalc
    entity_id: light.floorlamp_livingroom
    create_cost_sensor: true

Toggling cost sensor creation can also be done when creating sensors with the GUI, both in the global configuration and on a per sensor basis.

How the cost is calculated

The cost sensor reacts to changes of the energy sensor. On every update it takes the amount of energy consumed since the previous update and multiplies it by the price that is valid at that moment. When energy_price_surcharge is configured, it is added to the fixed price or dynamic price sensor value. When energy_price_multiplier is configured, it is applied after the surcharge. When you use a dynamic price sensor, a price change settles the energy consumed up to that point at the previous price before the new price takes effect. This way energy is always priced against the tariff that was active while it was consumed, and the accumulated cost stays correct even when the price changes over time.

Limitations / tariffs

Fixed per-tariff prices (for example a different fixed peak and offpeak price used together with utility meter tariffs) are not supported yet. If your utility uses different tariffs throughout the day, use a price sensor that already reflects the currently active tariff price — the accumulate-at-consumption behavior then yields the correct multi-tariff cost without any extra configuration. Native support for fixed per-tariff prices is planned for a future release.