This International Standard gives guidelines related to energy efficiency in buildings as introduced in ISO 16813. The objectives of this International Standard are to assist designers and practitioners when collecting and providing the useful data that are required at different stages of the design process and to fulfil the definitions of the building as prepared by building designers. This International Standard applies to new buildings and is applicable to space air-conditioning equipment and the heating plant in new buildings. It is assumed that the conditions of indoor spaces are maintained within a comfort range with regard to temperature, humidity, air quality, acoustics and light, or conditions maintained to provide freeze protection for piping or stored materials. Systems to be considered when assessing the energy efficiency of the building are heating, cooling, lighting, domestic hot water, service water heating, ventilation and related controls.