This graduate thesis represents the solution of the heating, cooling and ventilation system of a family house located in Zagreb. Living space is 139 m² of living space, consisting of ground floor and first floor. Drawings and schematic diagrams make the definition of the size of a family house and the space between them alone. The introductory part consists of providing general heating features with an emphasis on the characteristics of central heating and its features. Heat sources are also analyzed in heating systems. When elaborating a task, the process of heating system and consumable hot water is shown as needed to perform installation of a family house. After the calculation was made, the dimensioning of the system was started and all necessary equipment for the installation of the heating system and consumable hot water was selected and elaborated. The design solution selected gas condensing boiler with hot water tank. Heating is a combination of radiator and floor heating, while hot water heating is provided by solar collectors. Cooling is provided only in the living room and dining room because it spends the most time there, and it is also the area with the most heat gains. Ventilation is provided in all bathrooms mainly due to the extraction of waste air in winter. At the end of the work, a comprehensive conclusion is made. HRN EN 12831 norms are used for heat loss calculations (winter), and VDI 2078 norms are used for building thermal gain calculations (summer). Zagreb's outdoor design temperature is -18ºC.