Energy Efficiency

Improving the efficiency with which the energy is used while maintaining or improving the level of energy service.

Source: UIE Guide to Electric Load Management in Industry

This can be defined in slightly different ways, and includes using less energy (kWh) to achieve the same benefits (e.g. internal temperature, industrial output etc), or using the same or a lesser amount of energy (kWh) but achieving more benefits (e.g. a warmer home, higher output). The focus tends to be on improving the welfare of the enduser.

Source: SERN Glossary