Comparing the thermal value of cavity insulation and loft insulation boards: in comparison to other insulation materials like mineral wool or the widely used Polystyrene foam rigid foam PIR term insulation boards provide a much more effective insulation value. They guarantee a cost-effective and longterm solution for thermal insulation.
ʎ= 0,023 W/m2K
If you need to pick 200mm of mineral wool to assure a certain insulation value you may achieve the same result with just 110mm of PIR Term insulation board