I use Home Assistant and EVCC to manage energy in my (nearly) carbon neutral home. They coordinate the solar panels, heat pump, EV charger and battery. With dynamic energy pricing, my home energy management system (HEMS) shifts consumption to use more of my own solar power and keep costs down.

The setup

The hardware is:

• A 10 kW solar inverter with matching panels on the roof
• An Indevolt battery for storing excess solar energy
• An R290 heat pump for heating and domestic hot water (DHW)
• An EV charger managed by EVCC

Home Assistant handles general home automation, and EVCC manages EV charging. Together, they shift consumption to sunny hours or periods with the lowest EPEX spot prices.

The strategies

Shift heating to daylight hours

The heat pump is the biggest consumer in the house. By increasing the heating setpoint by +2°C during the day, the house absorbs enough thermal energy to coast through the evening and night. This way, the heat pump mostly runs when solar production is at its peak.

Smart EV charging with EVCC

EVCC handles the EV charging with two modes:

• Solar-only: charge exclusively on surplus solar energy
• Cheapest hours: when solar isn't enough, charge during the cheapest EPEX spot price windows

With these two modes, I can usually charge the car at the lowest available cost.

Kitchen boiler on a schedule

The kitchen boiler is only powered on during daylight hours. There's no need to keep water warm overnight, and by the time we need hot water in the morning, the sun is usually up.

Boost domestic hot water at peak solar

Between 12:30 and 13:30, the DHW setpoint is increased from 35°C to 55°C. This is the window with the highest solar production, so the heat pump can heat the water tank almost entirely on solar energy.

Legionella run on Sunday afternoon

The weekly legionella prevention cycle (heating DHW above 60°C) is scheduled for Sunday afternoon. Solar production is typically high then, while electricity demand is low.

The result

Most of the heavy energy consumption now happens during solar production hours. When solar can't cover it, the dynamic pricing fallback shifts consumption to the cheapest hours. The battery bridges short gaps and reduces peak grid consumption.

Todo:

• add something about capacity tarrif