Recently, aerogel has been considered one of the most promising high performance thermal insulation material in building applications. It has lower thermal conductivity and higher thermal stability than ordinary thermal insulation materials without showing signs of either physical or chemical deformations. This research investigates the thermal performance of an aerogel as well as its applicability as an insulation building material by mixing aerogels with cement. Before mixing the aerogels into cement pastes stably, the preparation of sol-gel aerogels was studied. Aerogels of 0.5, 1.0 and 2.0 wt.% of the cement weight in a water / cement mixture at 1:2 ratio were tested. The surface area and pore size distribution of the aerogel were measured by Brunauer-Emmet-Teller (BET). The stability of the aerogel was checked by TGA in accordance with the relation temperature with gravimetric losses of the aerogels. The chemical and physical stability of the aerogels mixed into the mortar was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The thermal conductivity of the aerogel cement (AC) was measured by the thermal conductivity analyzer (TCi).