Within the final paper, heating installation and preparation of consumable warm water has been calculated and designed with using condensation boiler and solar collectors. System is being used for residential-business building, with three apartment and one business premises with a total usable area of 371,83 m2. The building is located at area of city of Široki Brijeg, Bosnia and Herzegovina. Extra light fuel oil is being used like energy source for a heating of building. For system dimensioning heating losses have been calculated for designed conditions in winter period according to norm HRN EN 12831. Therefore, all components of heating system and preparation of consumable warm water have been dimensioned, calculated and chosen, that are necessary so system can work correctly. Temperature regime of heating is 55/40°C.The condensational oil boiler for central heating with of power of 35kW has been chosen. For a heating transmitter link heating bodies from company Lipovica are being used. For warm water preparation, accumulation system with bivalent container which is being heated by solar collectors is being used, with a support of condensation boiler. Bivalent container with nominal size of 400 l is chosen. Laminated collectors with a gross area of 7,11 m2, connected in a line, are mounted on the roof. The roof which on the collectors are is south-east orientation with inclination of 22°. Solar system completely covers yearly needs for heating of consumable water in June and July, and total covering rate for a year amounts 0.68. Heating system and system for preparation of warm consumable water is completely equipped with all necessary armature and regulation elements for fully automatically work. In the paper, the necessary energy for one year has been calculated according to HRN EN ISO 13790, based on energetic level of building has been determined and according to him residential and business space belong to energetic level B. With the paper, technical documentation is attached which contains drawings in which is determined the location of equipment by story and also functional scheme of connecting and automatic regulation.