The aim of this work or project was to determine the most optimal system of heating, cooling and preparation of domestic hot water, all with the aim that the facility has almost or completely zero energy consumption. To achieve the same, a heating and cooling system was created that includes a heat pump, fan convectors and underfloor heating with a mechanical ventilation system, while for the preparation of hot water a system was used that combines either the heat pump alone in the system or the same one integrated into the system with solar collectors. In order to compensate the consumption of electricity with its own production, a photovoltaic system was used. The entire project was created in the Trnsys program Simulation Studio, in which the simulations of the mentioned systems were completely carried out. The SketchUp program was also used to create a 3D model of the object itself. By analyzing the energy produced for heating and cooling purposes and, incidentally, the consumption of electricity to achieve the same, i.e. to ensure the operation of the system, and by comparing it with the electricity produced, it was possible to realize that the building is energetically independent of the external network. However, it also turned out that in order for the building to become energy independent, much higher investment costs of the systems themselves are required, which means that it is financially more profitable to use systems that do not have installed solar and photovoltaic systems.