This standard describes generic measuring and calculation methods to evaluate the energy efficiency of multiple components connected in a system called a functional unit. The system is further characterized by integrating multiple functions to achieve an overall goal. The purpose of this standard is to allow for the comparison of the energy efficiency of various functional units, thus ensuring that efficient design is rewarded. The standard is limited to functional units for which a “unit output” can be clearly defined and which require energy to function. The standard only covers energy consuming functional units. This standard deals with five types of functional units: a. Pressure functional units b. Flow functional units c. Lighting functional units d. Heating/Cooling functional units e. Mechanical functional units The standard requires specific information about the individual components forming the functional unit, the ship and how the functional unit will be integrated on board. The energy efficiency is evaluated using a specified set of global ambient conditions. The energy efficiency is also evaluated using ambient conditions for operation in arctic, tempered or tropical regions.