Sash of the coupled window EV31/IV68 consists of two parts. It is based on a 68mm thick standard German system sash with a single-chamber 24mm insulating glass unit and two sealing contours. A 31mm thick outer sash with 4mm glass is attached to it and locked using special fittings forming a 100mm thick sash construction. When looking from the outside, the sash is practically in the same plane with the frame visually imitating the historic chamfered window. The coupled sash opens inwards. When the window is open, the outer sash can be released and opened to wash the glasses from the inside. The thickness (construction depth) of the frame is 78mm.
Thermal conductivity coefficient of the window UW=1.0 W/m2K (according to DIN EN ISO 10077-1), sound absorption 36 dB.