Abstract: The subject of the invention is modular system for utilization of solar energy for heating of sanitary water, which is composed from individual modules, each of which comprises a prefabricated, upper-outflow transparent (diaphanous), translucent or non-transparent element (1), one or several intermediate transparent (diaphanous), translucent or non-transparent element(s) (2), and a lower-inflow transparent (diaphanous), translucent or non-transparent element (3). Their mutual connection by means of junctions (4a, 4b) enables flow of nontransparent media from one element to the other while absorbing solar energy. Several modules can be mutually and in parallel connected to the modular system replacing the existing roofing tiles. The choice of an appropriate color for the nontransparent media makes the system compatible and consistent with the look of surrounding existing roof tiles.