Energy efficiency is defined as the “ratio between the useful output of the end-use service and the associated energy input” (World Bank and IEA 2014). The IEA (2014b) defines it as the relationship between the energy requirements of a certain device (for example, a light bulb, boiler, or motor) and the service that the technology provides (for example, lighting, space heating, or motor power). In other words, energy efficiency can be equated with delivering more services for the same energy input, or delivering the same services for less energy input. It can be achieved through better performance, the use of more energy-efficient equipment, or a change in consumer habits. The experience of many countries in Asia and the Pacific provides the economic case for achieving this goal. In the PRC and India, for example, energy efficiency initiatives have reduced energy intensity and resulted in energy savings (ADB 2013b). Energy efficiency is also an important enabler for energy access. Greater efficiency frees up resources to expand the reach of energy, lowers the cost of energy for consumers, and creates a surplus that allows more energy to be used for productive undertakings.