Basically, there are two options for ensuring the hot water supply: Centralised, coupled with the heating system Decentralised via flow heater or small water tank Important to know: these devices can be operated using electrical energy, but this is not necessarily practical. Since it is relatively expensive. With electrical energy you can feed power peaks and receive basic heat from renewable energy sources, for example with the help of a solar system. This allows you to heat about 60 percent of your annual hot drinking water supply. Clarify at an early stage of the planning of your new building what conditions should be fulfilled for a solar system. Examples here are the areas on the roof, the inclination and the shading.