The project tackles the problem of thermal loses in buildings aiming for improvement and development of energy efficient windows, by using abundant, conflict free, low cost elements and an eco-friendly synthesis methods. The main objective is to demonstrate the design and fabrication under laboratory scale conditions of a novel multilayer structure for energy efficient glazing, in the form of Transparent Heat Reflector (THR). For this purpose, the project brings an alternative solution to the existing Low-E coatings architecture, in the form of multilayer structures based on copper as reflecting metal layer, enveloped by SiNx dielectric layers. Different structures will be designed theoretically, obtained experimentally and compared in terms of efficiency, endurance and overall performance. The use of SiNx comes with a few advantages, such as good optical properties, chemical stability, scratch resistance, etc., having also the potential to limit the oxidation of Cu layer both at the interfaces and during its deposition, lowering the detrimental effects of forming an oxide. The current project also proposes a new approach for the deposition process by using a combination of DC, HiPIMS and hybrid DC/HiPIMS magnetrons puttering, taking advantage of their potential different outcomes, in order to provide a high degree of tunability for a series of relevant properties, such as complex refractive index, electrical properties, resistance to oxidation, crystallinity, etc. The experimental part will be step by step guided by advanced optical modelling, thus the multilayer concepts will be continuously updated and optimized in order to obtain structures with the best optical properties, high stability and reproducibility.