Abstract: The financial and economic crisis in Greece has changed the balance between the fossil heating fuels and the biomass. Biomass is a renewable energy source and replaces fossil fuels in existing heat devices. The aim of this study is to investigate the financial feasibility of a Biomass Heating System in Greece. The RETScreen Software was used in order to predict the financial viability and the green house gas emissions reductions in cities which are placed in areas with very different climatic conditions.