Microporous boards are manufactured by mixing high quality agglomerates of pyrogenic silica and selective grade opacifiers along with filaments and pressed at a very specific pressure range to achieve a very narrow range of optimum highest possible porosity and unique range of densities to deliver a product with lowest possible heat loss through conduction, convection, radiations, and gaseous conduction. The thermal conductivity of Microporous insulation is lower than the still air at high temperatures.