Currently, energy efficiency is considered one of the main areas of investment, both by governments and organizations, as its implementation leads to a reduction in energy consumption and consequently reduces dependence on external energy sources, which has a positive impact on economic competitiveness and social development. Within this context, public lighting becomes relevant, as it has great potential in terms of its ability to reduce consumption, largely due to the outdated systems that are still common in public thoroughfares. Thus, aiming to implement a new system through a direct replacement of lighting equipment in the Santa Fé neighborhood, in Dourados-MS, a case study was conducted to assess the financial feasibility of this project, by directly replacing low-pressure sodium vapor lamps with modern LED lamps and subsequently conducting a financial analysis using the indicators NPV, IRR, and Payback. The analysis of the expected cash flow for the acquisition of the luminaires presented positive results and indicated that the lighting system upgrade is a profitable investment. With an investment value of R$136,300.73, the net present value was R$61,245.63. Additionally, the expected internal rate of return for the investment was 22%, indicating a good return on investment. The Payback, which is the period required to recoup the investment, was estimated at 6.93 years. Based on these results, it is observed that the investment is viable and can bring considerable financial benefits.