Energy-independent and self-sufficient buildings are a part of sustainable development. The share of houses with installed solar thermal collectors is growing. Collectors usually are used for hot tap water preparation but when there is no hot tap water consumption for a long time, the collector's temperature increases that lead to collectors overheating, stagnation, and potential solar energy loss.

Decentralized solar thermal collector connection to district heating system may solve stagnation problem, increase total solar energy fraction, and allow to remove the hot water storage tank from houses. In absence of local thermal energy consumption, energy can be feed into the grid and used by neighbors or accumulated in seasonal thermal energy storage. In such a way the household becomes a prosumer and can consume and produce thermal energy. The heat carrier must be injected into the district heating system with a defined temperature with a lack of temperature oscillations.