Our windows are air and watertight.
A test bench test validates this performance. Our windows are airtight in class 4 according to EN 12207; they are even too airtight with only one seal. Multi-leaf windows have a double seal on the crossing of the leaves. It is the user's responsibility to regularly ventilate his dwelling; see our optimal room ventilation section. A 2nd seal is only suitable for sound requirements above 38dB, see our acoustic section. In the event of a leak, please check to see if the gasket is securely in place. If after replacing the seal the problem persists or if you notice that the seal is damaged, please contact our maintenance department.