Home Assistant Energy Dashboard: track devices without double counting

Power tells you how much a device is using right now and is measured in watts (W). Energy is the amount used over time, commonly measured in kilowatt-hours (kWh). A simple analogy is a car: power is its speed, while energy is the distance traveled. Use a power sensor to view current load and an energy sensor to track daily or monthly use.

In Home Assistant, open Settings → Dashboards → Energy and start with the main source: your grid meter or a compatible energy monitor. Add solar production, a battery, gas, or water if relevant. This gives you the whole-home picture before you break usage down by appliance.

A smart plug with energy monitoring can track a single appliance when its ratings suit the appliance and installation. Some inverters, air conditioners, and boilers already expose power or energy sensors through their integration. A plug reports the connected appliance, while the main meter reports the home’s combined usage.

Before adding a sensor, check its attributes under Settings → Developer tools → States. Energy sensors need `device_class: energy` and `state_class: total` or `total_increasing`, with a supported unit such as kWh. Power sensors need `device_class: power`, `state_class: measurement`, and W or kW. If a sensor is missing from the Energy Dashboard list, check these attributes and the statistics provided by its integration.

If a device only reports power in watts, create an Integral helper in Home Assistant. It estimates energy from power readings over time, and the resulting sensor can be added to the Energy Dashboard. Accuracy depends on how frequently the source updates: more frequent readings provide a better numerical approximation.

An estimate from sparse or unreliable readings is not a substitute for a proper meter. Check the output unit, sensor update rate, and long gaps where the reading is unavailable. For accurate tariff billing, use a utility meter or a certified energy meter; treat an integral sensor as a monitoring and comparison tool.

If a circuit meter measures the kitchen and you separately add a measured kettle on that circuit, totals can be inflated. In the Energy Dashboard, set an upstream device relationship between a parent circuit and its child loads. Home Assistant uses this hierarchy to show how local usage relates to the larger source without counting it twice.

Start with a few measurements that answer real questions: overnight base load, a washing-machine cycle, or water-heater use. Compare similar time periods, inspect spikes, and create an automation only after you understand the graph. A dashboard alone does not guarantee savings, but it can show where a schedule or equipment setting may be worth changing.