IEA (2013), Technology Roadmap - Energy Efficient Building Envelopes, IEA, Paris https://www.iea.org/reports/technology-roadmap-energy-efficient-building-envelopes
The building envelope – also known as the building shell, fabric or enclosure – is the boundary between the conditioned interior of a building and the outdoors. The energy performance of building envelope components, including external walls, floors, roofs, ceilings, windows and doors, is critical in determining how much energy is required for heating and cooling. The building envelope’s impact on energy consumption should not be underestimated: globally, space heating and cooling account for over one-third of all energy consumed in buildings, rising to as much as 50% in cold climates and over 60% in the residential sub-sector in cold climate countries. Overall, buildings are responsible for more than one-third of global energy consumption. While whole-building approaches are ideal, every day building envelope components are upgraded or replaced using technologies that are less efficient than the best options available. These advanced options, which are the primary focus of this roadmap, are needed not only to support whole-building approaches but also to improve the energy efficiency of individual components.