In this example, excess photovoltaic power is fed into the house grid via an 800 W micro PV inverter. The fothermo switching device is required as an energy manager for this.
The switching device feeds excess energy into the grid when the solar heating element has finished heating or when more photovoltaic power is available than the heating element can convert into heat.
On particularly sunny days, the switching device starts feeding in partial surplus power from 1 - 2 modules early in the morning. This ensures that the house's basic electrical load is covered in the morning hours.
This way you save not only on hot water costs but also on electricity costs.