Building performance is an attribute of a building that expresses how well that building carries out its functions. It may also relate to the performance of the building construction process. Categories of building performance are quality (how well the building fulfils its functions), resource saving (how much resource is needed to fulfil its functions) and workload capacity (how much the building can do). The performance of a building depends on the response of the building to an external load or shock. Building performance plays an important role in architecture, building services engineering, building regulation, architectural engineering and construction management. Prominent building performance aspects are energy efficiency, thermal comfort, indoor air quality and daylighting.