With the rapid development of digitalization across most industry sectors, data processing through data centres has become increasingly necessary. As a result of the many different types of data application scenarios in areas such as the Internet, finance, transportation, and smart homes, cloud data centres and edge data centres have gradually been established to meet these needs. With the widespread deployment of cloud and edge data centres, energy savings have become increasingly important for data centres worldwide. The objective of this Recommendation is to clarify the requirements for designing the energy-saving aspects of cloud and edge data centres and to promote their wider adoption on a large scale in the future.