Light glass fiber felt (density 10 kg/m3), a porous composite consisting of 83% glass fibers (the average diameter 1.5 µm) and 17% phenolic resin, is usually used to increase sound insulation in the aerospace industry. The purpose of this research is further to improve the uniformity of light glass fiber felts by process optimization, analysis of microstructural forming mechanisms and physical properties. Light glass fiber felt is produced by the flame blowing process. The results show that process optimization can effectively improve the uniformity of light glass fiber felt. Light glass fiber felt exhibits a micro-layer structure seen as consisting of a number of “three-layer” structures, that is dense (more fibers)-loose (less fibers)-dense structure. In addition, process optimization can improve the stability of permeation rate and enhance sound insulation performance, which makes light glass fiber felt an excellent sound insulator.

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Temperature maintenance is one of the leading factors for the large-scale energy consumption in buildings, which accounts for 33% of the total consumption. The heavy smog in China resulting from the depletion of fossil fuels necessitates the development of new technologies that can reduce the energy usage in buildings. Several techniques for building’s thermal insulation were developed among which the utilization of Vacuum Insulation Panels (VIPs) has the leading edge. For refrigeration purpose in VIPs, the glass wool is being used as a core material because of their low thermal conductivity (λ ≤ 2 mW/m·K) and low cost. However, the silica-fly ash has been preferred as a core material of VIPs for buildings because of its high compressive strength (σc > 2 MPa) and the most economical price. Moreover, the P1/2 of the glass wool VIP and silica-fly ash VIP are 10–100 and 1000 Pa, respectively. In this work, the performance of VIPs with various cores has been compared. The thermal conductivity of VIPs, along with the factors affecting thermal conductivity, such as density, thickness, internal pressure, and porous structures, have been evaluated. In addition, the effect of core materials on the cost of VIPs was also quantified. It is expected that the study will serve as a pioneering work in the foundation to development of the next-generation, low-cost VIPs used for building insulations.