Kistler also found that the thermal conductivity decreased even further under vacuum. However, in the 1930's thermal insulation was a low priority and applications of aerogels in insulation systems was not pursued. It was then readily apparent that silica aerogels were an attractive alternative to traditional insulation due to their high insulating value and environment-friendly production methods. Unfortunately, the production costs of the material were prohibitive to cost-sensitive industries such as housing. The sum of these three components gives the total thermal conductivity of the material.
Solid conductivity is an intrinsic property of a specific material.
Therefore, thermal transport through the solid portion of silica aerogel occurs through a very tortuous path and is not particularly effective. These gases can also transport thermal energy through the aerogel. The final mode of thermal transport through silica aerogels involves infrared radiation. At low temperatures, the radiative component of thermal transport is low, and not a significant problem. At higher temperatures, radiative transport becomes the dominant mode of thermal conduction, and must be dealt with.