To learn why we use Roxul Insulation (Stone Wool Insulation), here is the brief history and benefits/features of stone wool.
Origin & Properties of Stone Wool
Stone wool was discovered on the islands of Hawaii at the beginning of the century. It occurs there naturally as abyproduct of volcanic activity. In its manufactured state, stone wool combines the power of rock with the characteristics of typical insulation wool. In addition, thanks to its non-directional fiber orientation, it also exhibits some unique and valuable characteristics.
Stone wool is an excellent insulator and a vital component of an energy efficient building. In fact Insulation saves 12 times as much energy per pound in its first year in place as the energy used to produce it. [http://www.naima.org/pages/benefits/environ/effic.html]