Within this study several heating systems for households were analysed (gas boilers, heating pumps and pellet firing). After a short introduction of the ecological performance of these systems, this study focuses on their profitability. In a first step, the heating installations had to be dimensioned for a low energy house. Afterwards, the economic calculations were done for a period of 25 years. The necessary data were gained by literature, offers from companies, expert interviews and appropriate market analysis. The applied comparison was done by use of the annuity method, which is the basic computation technique for building services engineering due to the guideline VDI 2067. Depending on investment, operation and consumption costs, an annuity is calculated for every year on the basis of which the different facilities can be compared. Additionally, the calculations were also done with another method called dynamic comparison method, which was developed within this thesis. It extends the annuity method, as opportunity costs and flexible credit periods are included. Especially the last extension makes the dynamic comparison method a very useful technique for practical applications. Basically it has been observed, that in all performed comparisons, heating pumps have considerably lower costs than the reference systems. The long term performance of gas boilers and pellet firing systems is almost identical. For the analysis, all calculations were done in general as well as including various subsidies. Therefore, the results allow conclusions regarding the actual system and to make suggestions about a possibly improvement of it. The entire computation was done by use of the spreadsheet software Open Office Calc. Therefore, with a few modifications the calculation program can be adapted to various other energy systems. For that reason, beside the comparison of heating facilities, another analysis was done for electrical energy systems. In particular, conventionally purchased photovoltaic facilities in two operation modes, grid connected or grid parallel were analysed. Here the results were clear: Regarding austrian radiation rates, PV-systems are not competitive compared to conventional purchased electricity. However, including the current subsidies, both PV-modes can be considered to be a profitable future investment.