This paper shows the productivity of grid-connected photovoltaic systems, to plan future investments in the region around Klagenfurt, Austria. To evaluate the usage of grid-connected PV systems, a methodology based on mainly three factors is presented. These factors are yield factor, capacity factor and cost of energy. The analysis is done by a model based on monitored PV data and meteorological data in an interval of 15 minutes. Meteorological data was recorded from May 2013 until July 2014 with a lack of data from September 2013 until January 2014. By analyzing the collected data, it is found that the daily average solar energy in Klagenfurt was 6613Wh/m2 in the time of research. The results of the research show that future investments in grid-connected PV systems in Klagenfurt can be profitable. The yield factor over the time of research (293 days) is 1263.4kWh/kWp, whereas the capacity factor of the proposed system is 17.97%. The cost of energy is found to be 0.2348€/kWh. This is a satisfactory result compared with values of other European counties.