The United Kingdom (UK) is rich in renewable energy sources, including solar and wind energy. This paper explores the potential and economic feasibility of placing solar panels on the roofs of residential buildings in London, estimating the additional benefits and savings. For this purpose, we utilized the System Advisor Model (SAM) software to perform and evaluate economic and technical potential of integrating a solar photovoltaic system into the grid. Our study evaluated several critical factors such as the system’s capacity, net present value, return on investment, cost of energy, and the payback period. The results obtained from this study recommend installing a 20.4 kW solar photovoltaic system; the simulations have shown that the system could cover 83% of a typical residential building’s electricity consumption. The results revealsed a Levelized Cost of Energy (LCOE) of $0.069 per kWh and a Net Present Value (NPV) of $7,365, demonstrating the effectiveness of the renewable energy potential.