This article presents a comprehensive approach to assessing the economic efficiency of investments in energy-saving measures specifically for public utility enterprises. This study contributes to the theoretical and practical justification for using efficiency evaluation criteria, such as net present value (NPV), return on investment (ROI), and internal rate of return (IRR) for energy projects. Analysis revealed that the highest electricity consumption occurs in the winter period—approximately 246,923 kWh when using 90 W lamps operating 16 h per day. In the summer period, with an average daylight duration of 8 h, consumption decreases to 31,298 kWh. This difference is due to the influence of temporal and seasonal factors, highlighting the need for a comprehensive assessment of energy-saving measures’ effectiveness across different times of the year. Furthermore, a methodology for calculating and utilizing the payback ratio was proposed, according to which, by reducing lamp wattage from 90 W to 60 W and operating hours from 16 to 8 h, companies can reduce electricity costs to 21,076 kWh in the summer period, demonstrating potential savings of 1.5 to 2 times. This study also proposes specific financing schemes for energy efficiency projects, enabling the more accurate assessment of needs and the optimization of energy consumption under limited budget conditions and high environmental requirements.