Sustainable architecture is when a building is created and used as environmentally sustainable as possible.
True sustainable architecture will use a given site's climate conditions to passively heat, cool, and ventilate it.
In the broad context, sustainable architecture seeks to minimize the negative environmental impact of buildings by enhancing efficiency and moderation in the use of materials, energy, and development space.
For a home builder in the Gulf coast area, a home that blows down and needs to be rebuilt with each hurricane season so he can sustain his income.