In this thesis, the project of the mechanical installations of the holiday home was elaborated, which includes the project of heating, coolnig, ventilation, preparation of domestic hot water, outdoor and indoor pool heating. The house is located in the village of Fabci, near Poreč. The main source of thermal energy is an air-water heat pump located near the house, which has the possibility of simultaneous and independent production of cold and hot water, depending on the needs of the system. The need for heating and cooling arises during the summer months when, in addition to cooling the building, heating of the outdoor and indoor swimming pools is required, as well as the preparation of DHW. The space is heated through a floor heating system, fan coils and bathroom electric heaters. The space is cooled by a floor cooling system, wall cooling system and fan coils. The preparation of DHW takes place in a 750 l tank heated by a pipe and electric heater. Temperature regulation is done via wall controllers that control the temperature of the room in which they are installed. Ventilation is required in the part of the basement where the indoor pool is located, and where there is a need to drain the evaporated water from the indoor pool. The ventilation distribution was made with round ducts wherever possible, and the rest was made with rectangular ducts.