As available energy sources have grown increasingly scarce, people have started paying attention to their energy consumption. Although many methods for power generation are being actively investigated, efficient methods for solving energy problems must be based on reducing energy consumption. Thermal insulation can decrease heat energy loss and conserve energy waste, especially in the construction, transportation and industrial fields. In this study, polyester (PET) hollow fibers were blended with various ratios of low-melting-point PET fibers (10%, 20%, 30%, 40% and 50%). The fibers were blended using opening, carding, laying and needle punching (150 needles/cm2, 225 needles/cm2 and 300 needles/cm2) to prepare PET nonwoven fabrics. The PET nonwoven fabrics were thermally plate pressed (TPP) and air-through bonding (ATB). Thermal conductivity, physical properties and air permeability were investigated to identify the influence of manufacturing parameters on the PET nonwoven fabrics. The experimental results show that needle punching density, TPP and ATB would influence the thermal conductivity of PET nonwoven fabric, because the structure of PET nonwoven fabric was changed. The optimal parameters of PET nonwoven fabric clipped with an aluminum foil was used to evaluate the influence of aluminum foil on thermal conductivity. The PET nonwoven composite in this study can be used in industrial thermal insulation applications.