The final thesis is a project on heating, cooling, and ventilation system along with energy renovation, for a family house in the city of Rijeka. An analysis of the current energy condition of the building has been done. The thickness and layers of walls, floors, and ceilings were determined followed by heat transfer coefficients calculation. The existing system for the preparation of domestic hot water and heating systems has been described. Based on the calculation with reference values, the annual energy consumption for heating and preparation of domestic hot water (DHW) was obtained, and the current energy class of the building was defined. By choosing the correct materials for the insulation of the outer walls and ceiling as well as for the replacement of the carpentry, energy renovation could have started. After we insulated the outer walls of the building with mineral wool of 15 cm thickness and with 5 cm thickness for the ceiling, we achieved annual savings of 47.29 kWh/m 2 and reach energy class B, which is sufficient according to nZEB when it comes to renovating buildings. After the achieved energy savings, we chose new equipment for heating, cooling, and domestic hot water system, and a solar power plant was installed on the roof of the building, which will reduce energy consumption costs in the long run