Driven by environmental concerns, energy shortage, and decreasing cost of system components, renewable energy resources have been widely adapted in the world. Among these renewable energy sources, photovoltaic (PV) energy generation has attracted significant interest. Currently, solar energy systems are more practical, cheaper and suitable for building applications in big cities compared to wind energy systems. However, the performance of such systems depends mainly on two things: the type of solar panel used and weather/environmental conditions (solar radiation, temperature, shading effects, etc.) at the site. Therefore, site specific analyses will provide more reliable results for feasibility and economic analyses. In this study, two common types of solar panels (monocrystalline and polycrystalline) will be evaluated in terms of their power and energy production capacities in Istanbul-Turkey. An experimental setup is used to collect each panel voltage and current data under same loading and environmental conditions. The goal is to obtain actual performance of these panels. Evaluating field performances of both solar panels will be an excellent reference for people considering solar energy for their homes in Istanbul. The results can also be used in feasibility and economic analyses of such systems.