① The higher ceramic wool insulation heat resistivity is, the better insulation efficiency becomes.

      Insulation materials has many gaps, resulting in a light weight of the materials. Air in the gap has a low thermal conductivity, thereby having a insulating function. However, we cannot think that the greater porosity is, the better the insulation efficiency becomes.

a: Open type air gap: Air in the gap will exchange with the outside and thermal insulation properties will be on the decline;

b: When the porosity exceeds a certain range, then, the space in the material becomes large and there will be a internal air convection. We all know that convective heat transfer is much larger than the radiation heat transfer, and at this time, the thermal conductivity is also reduced, resulting in decreased thermal insulation properties of the material.

② The lower thermal conductivity is,the better insulation efficiency becomes.

     Thermal conductivity is determined by the physical structure, the degree of compaction, structural characteristics, the impact of environmental temperature and humidity and heat flow direction. Generally speaking, inorganic insulation material has the maximum thermal conductivity and organic material has minimum one. When the composition is the same, crystalline amorphous material enjoys a higher thermal conductivity than amorphous material. The denser the material is, the higher the thermal conductivity becomes. When porosity is the same, material with fine pores or closed pore structure, its thermal conductivity is small. In addition, if there is water in the material, thermal conductivity will significantly increase. Thermal conductivity is bigger at high temperatures than that at  room temperatures. And it will be bigger if the fiber is smooth.