A boom in environmentally friendly building is kicking off in the US amid falling prices for "green" construction and strong demand for sustainable places to live and work.

The total value of new buildings seeking the US green building rating, known as LEED, rose 50 per cent to $15bn (€11bn, £7.5bn) last year. This year 1bn sq ft, or 6 per cent of all new construction, will be aiming for environmental ratings, up from 1 per cent five years ago.