The article discusses the management of electricity consumption in hospitals in accordance with ISO 50001. Hospitals are among the most energy-intensive public buildings, and efficient energy management is becoming crucial in the context of rising energy costs and environmental regulations. Lighting in hospitals accounts for about 17–21% of total electricity demand, and its efficiency has a direct impact on patient comfort, staff productivity and operating costs. The article presents two options for modernization of the lighting system: replacing light sources with LEDs and a comprehensive upgrade with new luminaires and a DALI control system. Both options lead to a significant reduction in energy consumption, with one modernization offering a faster payback period. The introduction of appropriate technological solutions, such as lighting control systems and smart energy management, further optimizes energy consumption. The results indicate that the implementation of modernization can reduce electricity consumption by 40%, which has a positive impact on the environment and a reduction in operating costs.