This sub-metric is used to evaluate the metric : ""3.2 Efficiency and energy saving""
With this metric we refer to the 2 most important aspects of sustainable energy consumption: Efficiency and Savings.

Energy saving involves a change in consumption habits such as avoiding energy waste.
Energy efficiency is the fact of minimising the amount of energy needed to satisfy the demand without affecting its quality; it means replacing one piece of equipment with another that, with the same performance, consumes less electricity, for example.