Autoclaved aerated concrete (AAC) is known to be a construction material with high heat insulation parameters. Therefore, it is widely used in construction where high heat insulation parameters of external delimiting constructions have to be met. However, there is a factor that has significant impact of the insulation properties of AAC. This factor is moisture content of the AAC material and its distribution throughout the cross section of the AAC masonry blocks. The moisture distribution and transfer processes depend on the pore distribution throughout the volume of the material and differ in different directions of the material volume. Therefore, the drying process of the AAC has to monitored in order to make sure that the material has reached air dry state and can reach its optimal heat insulation properties.