Assignment of this final work was to project the solar system for heating and DHW preparation of the one floor house for four member family in the area of city Rijeka. It includes several ways or methods for the main concept of the system. All methods are described, in addition the one with maximum efficiency, the most practical one and also with the least money investment needs is chosen as solution. Chosen variant is specific beacuse of the type of a storage tank which consists of two main parts. First one is boiler for heating purposes and another one is boiler for DHW preparation. Accumulation boiler is settled down in a storage room. As source of heat was selected 61 condensing boiler fueld by natural gas which, with help of solar collectors, serves as warmer of heating water in the system of radiator heating. All the remaining equipment is dimensioned and chosen by norms and it has analysis shown so how would thermotehnical system work normally without any manacle. This work was based on modern solutions, ecologically acceptable, with as much as possible savings of energy and emphasis on use of renewable energy sources such as solar energy.