Building insulation materials weak and brittle. Before its risks were recognized, it was used because it was a cheap, effective insulator with a high R-value and its open-cell structure was a good acoustic insulator. Though it absorbed moisture easily, it regained effectiveness as an insulator when dried. Asbestos once found common use as an insulation material in homes and buildings because it is fireproof, a good thermal and electrical insulator, and resistant to chemical attack and wear. It has been found that asbestos can cause cancer when in friable form (that is, when likely to release fibers into the air - when broken,
Building insulation high insulated performance was very expensive. With the development of material industry and the booming of science technologies, more and more insulation materials and insulated technologies have emerged during the 20th century, which gives us various options for building insulation. Especially in the cold climate areas, a large amount of thermal insulation is needed to deal with the heat losses caused by cold weather (infiltration, ventilation, and radiation). There are two technologies that worth discussing: VIPs are noticeable because of their ultra-high thermal resistance, their ability of thermal resistance is four to eight times more than conventional foam insulation materials