Carbon nanofiber-reinforced polymer aerogels have been successfully synthesized by means of a freeze-drying process. The influence of the different operation conditions on both the process efficiency and the aerogel physical properties has been evaluated. Morphology, porosity and conductivity of the resulting carbon nanofiber-reinforced polymer aerogels were investigated. Their density and porosity increased when the freezing time decreased. However, the porosity of the carbon nanofiber-reinforced polymer aerogels increased and when both the vacuum pressure and the freeze-drying temperature increased, respectively. No clear effect of the operating conditions on the thermal conductivity of the aerogels synthesized was detected, ranging from 0.037 to 0.069 W/m K. The low values of thermal conductivity obtained suggest that these materials could be used for building insulation purposes. In addition, the addition of carbon nanofibers allowed to increase the mechanical resistance of the final product to be used as building insulation materials to reduce the energy consumption.