A window reveal module for the decentralised heat recovery units - HRU-WALL series. The module is intended for installation in the facade, in the insulation layer, a ventilation grille is mounted on the window reaveal. The window reveal module provides practically invisiable solution for supply/extract ducting. This method of installation will be especially useful during the thermal modernization of the building. The product has a universal layout, the choice of "right-sided" or "left-sided" assembly is made at the construction site. In addition, a slope for possible condensation growth was implemented into the design.The duct is telescopic, which means that the distance from the axis of the HRU to the window reveal can be adjusted in the range of 380-490 mm.