The Tank in Tank container from MasterSol combines a boiler room boiler with a buffer tank and connects to the boiler or solar collectors. The installation of the tank-in-tank container provides better efficiency with simultaneous fuel savings and production of domestic hot water.

It allows the use of up to three different heat sources as well as optionally an electric resistance. Its purpose is to produce hot water either from the boiler or from the solar collector, store it, and provide it when the operation of one or the other ceases.

This results in the burner operating even fewer hours, minimizing the energy requirement for space heating. The insulating material surrounding the buffer tank maintains the water temperature for a long period, as the boiler or heat pump does not need to operate when the circulation of hot water is done from the water stored in the buffer tank.