The terminal building is one of the world’s most sustainable, incorporating a range of passive environmental design concepts, such as the south-east orientated skylights, which maximise heat gain from the early morning sun, and an integrated environment-control system that minimises energy consumption. Rather than the sprawl of many separate buildings, it uses less land by bringing everything closer together for ease of communication in one efficient structure, yet it is still 17% bigger than the combined floorspace of all of Heathrow’s terminals 1, 2, 3, 4 and the new Terminal 5. In construction terms, its design optimised the performance of materials selected on the basis of local availability, functionality, application of local skills, and low cost procurement.