Ratebook for Home Assistant

A Home Assistant custom integration that turns a Ratebook tariff into live electricity-price sensors and a cheapest-charge-window sensor — the price signal that EV chargers, evcc, EMHASS, and HA automations need to answer "what does a kWh cost right now, and when should I charge?"

It is a thin shell over the deterministic ratebook rate engine. The price math lives in the ratebook_ha package (unit-tested without Home Assistant); custom_components/ratebook is the HA binding (config flow, coordinator, sensors).

Entities

• sensor.ratebook_electricity_price — the current marginal price ($/kWh). Attributes today / tomorrow carry the full hourly price schedule ({start, price} per hour), the shape evcc and price-aware automations consume.
• sensor.ratebook_cheapest_charge_window — the start time of the cheapest contiguous charge block in the next 24 hours (timestamp). Attributes: end, avg_rate, hours.

Configuration

Add via Settings → Devices & Services → Add Integration → Ratebook. Pick a bundled example tariff (a generic time-of-use or flat residential plan) or paste a Ratebook tariff JSON, then set the charge-window length (hours) and currency.

A ready-made Lovelace dashboard (current price + hourly forecast chart + cheapest-charge-window) is in examples/dashboard.yaml.

Install

The integration is self-contained: the ratebook engine and ratebook_ha adapter are vendored under custom_components/ratebook/vendor/, so it has no PyPI or network dependencies.

Manual copy (works today): copy the custom_components/ratebook directory into your Home Assistant config/custom_components/ directory, restart Home Assistant, then add the integration via Settings → Devices & Services → Add Integration → Ratebook.

HACS: install from the distribution repo cbetz/ratebook-homeassistant — HACS → ⋮ → Custom repositories → add it as an Integration. That repo is a synced mirror of this directory with the root-level custom_components/ layout HACS requires (regenerate it with scripts/sync_dist_repo.sh).

Status: v0. Prices are the tariff's energy marginal price (time-of-use signal); demand charges and tier-vs-baseline position are not modeled — see the engine docs.