A basic challenge of the rehabilitation of facades is to eliminate the problems of moisture and select efficient thermal insulation. For years we have witnessed the discussions what materials and technology can be used for internal thermal insulation with exception of attics and underground. While internal insulation reduces heat loss by conduction it does not eliminate thermal bridges and opposite often increases their effect on condensation of moisture. Nevertheless, internal insulation can be a factor contributing to a high quality of internal environment and if combined with forced ventilation then also to control relative humidity inside façade. The work is now undertaken to determine how to address long-term hygrothermal performance of the whole wall assembly that is provided with additional means of heat and moisture control.