There are many advantages of aluminum alloys - low weight, good plasticity and resistance to corrosion. Aluminum constructions were used in a lot of representative buildings over past 15 years. Aluminum facade systems have dominated office and public buildings. Slowly this system also appears in residential constructions.
The basic elements of aluminum window system (including doors and facades) are the structurals. These are elements of opened and closed profiles, which combined make stable, inflexible and light construction of window sashes and outer frames. There are used special alloys of aluminum which are enriched with magnesium and silicon for their production.
Profiles that are made entirely from aluminum, despite air chambers formed from the combination of structurals, have low thermal insulation: U = 3.0 - 3.9 W(m2*K). It's called cold aluminum and it's used in facade construction and where is no need of thermal insulation. For housing construction there are used "warm profiles". Their structure usually contains two or three chambers formed by the merger of aluminum profiles, between which are placed thermal pads made of plastic. As the insulator there are used interlayers made of polyamide reinforced with fiberglass. Aslo there is possibility of adding sythetic rubber gaskets, which are an additional safeguard against interior cooling. They can be mounted on the pin of outer frames and sash. Aluminum window frames made from "warm profiles" have thermal insulation at U = 1.5-1.9 W/(m2*K) level, which is a value comparable to the wooden and plastic frames.
