"By the time the design for most human artifacts is completed but before they have actually been built, about 80-90 percent of their life-cycle economic and ecological costs have already been made inevitable." This is a quote from Amory Lovins, co-founder, of the Rocky Mountain Institute (RMI). It is used by The Natural Edge Project to explain why we need Whole System Approaches to Sustainable Design to counter many of the issues that now confront us. The TNEP is an independent sustainability thinktank based in Australia, who are involved education, research and policy development on innovation for sustainable development.
This particular Whole Systems project, with financial support from the Australian government and various other funding sources, is an attempt to provide educational materials (all freely downloadable) that will assist engineers, architects, industrial designers and urban planners in applying the principles of whole system design to their work. TNEP reckon such approaches can achieve 75% or greater efficiency savings in new designs. And a whole system designed house could realise a 29% reduction in lower cooling loads.
[Not that efficiency should be seen as an end goal. It has its own problems, like the dreaded Rebound Effect.]