In high-performance optical communication systems, transceiver health and efficiency are critical to network reliability and energy use. This presentation explores Versatile Diagnostics Monitoring (VDM) features in modern transceivers (>100G), focusing on Thermoelectric Cooler (TEC) current metrics. By analysing TEC current alongside temperature and cable length, we identify optimal operating conditions that minimise power consumption without sacrificing performance. Using software prototypes and real-world VDM data, this talk demonstrates how to evaluate and visualise transceiver efficiency in watts, providing practical insights for designing and operating more energy-efficient optical networks.