In the final thesis it is demonstrated the possibility of reconstruction of the heating plant due to the replacement of primary fuel. In the military naval quarters "Admiral of the fleet Sveto Letica - Barba", a medium light fuel oil is currently used as a fuel for the heating plant. This fuel has already replaced a heavy fuel oil, which had to be replaced due to its high emissions of harmful products. Due to the gasification of Dalmatia and the City of Split, which is under way by EVN Croatia Plin Ltd., the medium pressure natural gas pipeline is already laid near the military naval quarters. This opens the possibility of building a connecting gas pipeline for the military naval quarters in order to replace the existing fuel with the natural gas. In the thesis it is given a technical description of the current state of the heating distribution network and the heating plant, while using the simplified analysis it is demonstrated the possibility of reconstruction of the existing heating plant. Finally, a simple economic analysis is presented demonstrating the financial viability of the proposed reconstruction of the heating plant.