The aim of this thesis is to discuss the Material Flow Cost Accounting (MFCA) approach, to increase the resource efficiency of the Georg Fischer Fittings Ltd. However, finding those inefficiencies within the production system is the challenge that needs to be overcome. The methodology of the MFCA, according to ISO NORM 14051, bases on a consistent material and energy flow analyses and strives after a decrease of their consumption. By handling losses equal to products as a cost unit, this method increases transparency when showing the costs that arise from inefficiency. It therefore bridges a gap that other cost accounting systems leave open. First the flows are modeled in their physical units and linked with monetary units afterwards. This results in a flow cost matrix to evaluate the total cost for each process step. Based on this, the costs for the specific outputs are determined. From a performed ABC-analysis of the losses the priorities for measures to increase the efficiency can be derived. The effect of a reduction of the identified losses is calculated in scenarios, which show the potential for cost savings.