This paper compares the theoretical and actual efficiency of two solar panels, CTI-80 and YHM-205-27P, using Engineering Equation Solver (EES) software. The comparison is based on specific parameters, and the rationale behind their selection is explained. The results show that the CTI-80 panel is more efficient than the YHM-205-27P panel due to the monocrystalline solar cells, which provide more efficiency than polycrystalline solar cells. Although the YHM-205-27P panel has more solar cells, the CTI-80 panel is still more efficient. The temperature affects the theoretical efficiency, as it assumes that all photons have the energy to break the bond in the n-type layer, while in reality, not all photons have sufficient power. Both theoretical and actual efficiencies are lower than the theoretical efficiency due to temperature. The conclusion emphasizes the importance of choosing the right type of solar panel for a particular application based on its efficiency and recommends using monocrystalline solar cells for higher efficiency.