Aluminium is the most abundant metal in the earth’s crust. It is derived commercially from bauxite, an abundant, naturally occurring mineral which is estimated to have minable global reserves measured in the hundreds of years. This compares with a possible 50-year supply remaining for fossil fuels, the raw material for plastics or vinyl windows, and contrasts with renewable supply circles for timber, the raw material for wooden windows.
The smelting of aluminum and the extruding of aluminum profiles require large amounts of electricity for electrolytic and heating purposes. This requirement gives aluminium windows a high ‘embodied energy’. Offset against this is the favorable comparison between aluminium and alternative window materials for both recyclability and durability. Studies have indicated that aluminium and wood windows typically last over 40 years, while PVC has an optimum life of 25 years. Aluminium is notable for its ability to be recycled indefinitely owing to its high intrinsic value and the widespread industrial infrastructure devoted to re-melt and re-purification of the metal. Recycled aluminium accounts for one third of global consumption but there is considerable scope for the recycled content of global production to be increased.
Aluminium windows have unique properties of strength, light weight, ductility & corrosion-resistance. Because of the balance that needs to be achieved between energy conservation and the ideal allocation of energy rich materials to appropriate end uses it has been stated that aluminium is best used in applications where its unique properties are indispensable. The aluminium window and door industry maintains that its use in this sector is important and well justified. Aluminium windows have attributes of span, scale, strength functionality and aesthetic capability that alterative materials have difficulty in matching. Modern architectural trends and practices would be significantly impacted if exterior aluminium joinery was unavailable. Provided that maximum levels of recycle of scrap or demolition aluminium are achieved and other measures of environmental mitigation are implemented at all points in the production process, AWS believes that aluminium windows and doors offer an acceptable solution from the viewpoint of sustainability.