The use of the term ‘sustainable’ to refer to practically any building whose construction process has involved environmental concerns – from rainwater collection or energy use reduction to the choice of ‘ecological’ materials like bamboo –, has made ‘sustainable’ mean everything and nothing.

Currently there is no reference value to determine whether something is or is not sustainable, so we cannot state that some buildings are more sustainable than others in absolute terms, but rather that there are more or less sustainable approaches to issues at a given place and time...