wattcast
Wattcast × Home Assistant

A clearer view of when to charge.

Bring electricity prices and a seven-day forecast into Home Assistant. See the trend ahead, choose a day to charge, then refine the hours when market prices are published.

Install with HACS Explore the forecast
Free public API · No API key required · Four bidding zones
WATTCASTEE · FI · LV · LT

The week ahead

Illustrative trend · not live prices or a Home Assistant screenshot

TodayNext seven days
From forecast to a plan

If the car can wait, a cheaper day ahead may be worth considering. Confirm the hours once market prices are available.

EE · EestiFI · SuomiLV · LatvijaLT · Lietuva
01 / EV charging

Choose the day. Then choose the hours.

01

Start with the next trip

Decide how much charge you need and by when. Keep enough range for your plans, even if the forecast changes.

02

Look at the daily trend

Compare the days ahead. The forecast helps you decide whether to top up now or leave flexible charging for later.

03

Set the charging schedule

Once market prices are published, choose the hours in Home Assistant. Connect the schedule to your car or charger using its own integration.

02 / Home Assistant

Install with HACS

You need a running Home Assistant instance and HACS. Wattcast is a custom integration you can install directly from its repository.

HACS installation help ↗
  1. In HACS, open the three-dot menu → Custom repositories. Add this URL and select Integration:https://github.com/SectorTll/wattcast-homeassistant
  2. Download Wattcast in HACS, then restart Home Assistant.
  3. Open Settings → Devices & services → Add integration → Wattcast. Select EE, FI, LV or LT. Leave the default API address; no key is needed for normal use.
03 / Your dashboard

Prices and signals, ready for your dashboard.

Current 15-minute pricesensor.wattcast_ee_price
Tomorrow’s average · published or forecastsensor.wattcast_ee_tomorrow_average
The week aheadsensor.wattcast_ee_forecast
Cheap now · current hour in the lowest historical quarterbinary_sensor.wattcast_ee_cheap_now
Add a simple dashboard card

Add a Manual card to your dashboard and paste this YAML. These are example entity IDs for Estonia: check the actual IDs in your installation and replace ee for your zone where needed. The forecast row shows its update time; the hourly forecast is in its attributes.

type: entities
title: Wattcast
entities:
  - sensor.wattcast_ee_price
  - sensor.wattcast_ee_tomorrow_average
  - binary_sensor.wattcast_ee_cheap_now
  - sensor.wattcast_ee_forecast
Chart and automation examples ↗

Know what the numbers mean

Published market prices and forecasts are different. Forecasts are uncertain and can change; they do not guarantee a lower bill. The cheap-now signal compares the current hour with the lowest 25% of hourly prices over the past 30 days. It does not mean the cheapest hour today.

Integration prices are in ct/kWh, excluding VAT, network fees and supplier margins. Your electricity contract determines the final cost.

Wattcast provides price data and sensors. Control of the car or charger requires a separate compatible Home Assistant integration. Choose your own target charge and departure time.

Report a problem or ask a question ↗