Dreen Sustainable design

Sustainable "green" architecture is the practice of designing, construc- ting and  maintaining buildings in a way that their environmental impact is minimized. One of the most important aspects of sustainable design is energy efficiency - a drive  to reduce the amount of energy a building consumes over its life-span. The truth  of sustainable design is that approximately 80% of the design decisions that  influence a building's energy performance are made by the architect in the early  design phase; the remaining 20% are made by engineers at the later phases of design. Therefore it is crucially important for architects to be able to utilise a quick and reliable energy performance evaluation at the very early stage of the building design process.

While the practical application varies among disciplines, some common principles are as follows:

• Low-impact materials: choose non-toxic, sustainably-produced or recycled materials which require little energy to process

• Energy efficiency: use manufacturing processes and produce products which require less energy

• Quality and durability: longer-lasting and better-functioning products will have to be replaced less frequently, reducing the impacts of producing replacements

• Design for reuse and recycling: "Products, processes, and systems should be designed for performance in a commercial 'afterlife'.

• Design Impact Measures for total carbon footprint and life-cycle assessment for any resource used are increasingly required and available. Many are complex, but some give quick and accurate whole-earth estimates of impacts. One measure estimates any spending as consuming an average economic share of global energy use of 8,000btu per dollar and producing CO2 at the average rate of 0.57kg of CO2 per dollar (1995 dollars US) from DOE figures.
  

• Sustainable Design Standards and project design guides are also increasingly available and are vigorously being developed by a wide array of private organizations and individuals. There is also a large body of new methods emerging from the rapid development of what has become known as 'sustainability science' promoted by a wide variety of educational and governmental institutions.

• Biomimicry: "redesigning industrial systems on biological lines ... enabling the constant reuse of materials in continuous closed cycles.

• Service substitution: shifting the mode of consumption from personal ownership of products to provision of services which provide similar functions, e.g., from a private automobile to a carsharing service. Such a system promotes minimal resource use per unit of consumption (e.g., per trip driven).

• Renewability: materials should come from nearby (local or bioregional), sustainably-managed renewable sources that can be composted when their usefulness has been exhausted.

• Healthy Buildings: sustainable building green design aims to create buildings that are not harmful to their occupants nor to the larger environment. An important emphasis is on indoor environmental quality, especially indoor air quality.