Is wool more effective as an insulator than alternative materials?
Yes. Wool insulation has a very low conductivity which means it is very difficult for heat to pass from one side to the other. To compare wool to other common insulators examine the table below, here the conductivities are given in Watts per meter Kelvin (w/mK) – where the lower value is the better result.Insulation Material Conductivity (k Value) Sheep Wool Insulation (Certified Europewide CE Value) 0.039 W/mK Glass Wool 0.044 W/mK Mineral (Rock) Wool 0.042 W/mK Cork 0.04 W/mK The above values are typically measured at 0% humidity (i.e. laboratory conditions). Wool is a significantly more effective insulator once moisture is introduced into an environment, which typically occurs in everyday situations. Your attic may have 60% humidity for example, which will adversely affect materials which can not absorb this moisture. Wool is a hygroscopic insulator, which means it can absorb moisture without becoming wet to the touch and without affecting its superior performance.
