Climate change and global warming are the main challenges for today and the future nations from the health and environment perspectives. Energy generation utilizing fossil fuel is the leading cause of these issues. On its opposite side, elimination or suppression of fossil fuel utilization by introducing clean and abundant renewable energy resources could be the best solution. In general, renewable energies have low efficiency and high capital cost compared to conventional fossil fuel-based energy supply. Therefore, without considering proper approaches and techniques, it is not encouraging to supply energy through renewable energy resources. Conquering the problem, we need to find the best method and ways to create cheap and efficient energy by renewable sources as possible. In this paper, a methodology is investigated and proposed to simultaneously save energy and cost considering useful parameters such as the effect of different modules, temperature, location, and tilt angle. An estimation-based tool developed by National Renewable Energy Laboratory (NREL) known as PV Watts, which is utilized in this paper. A 10 kW photovoltaic system with three different modules in two different locations Kabul and Kandahar in Afghanistan is selected as a case study. From the results, it is found that selection of a specific module for a specific region with different temperatures and appropriate title angles has a significant effect on the performance of photovoltaic systems. It is worthy of mention that before implementing a photovoltaic system, different aspects of the system should be evaluated using proper software/tools in order to achieve optimal energy performance. Finally, better energy system performance contributes to the attraction of investment in renewable energy resources as a clean and sustainable energy supply option.