The COR 70 system with a hidden sash features an exceptionally slim frame. The exterior cross-section, measuring only 66 mm, allows for a significant increase in the glazing area, which can account for up to 85% of the window’s surface. This results in interiors being well-lit with natural light.


The window is designed so that from the outside, fixed glazing cannot be distinguished from operable ones, providing a uniform and aesthetically pleasing building facade.


Thanks to a 35 mm thermal break and polyolefin foam in the frame and sash, the window achieves a thermal transmittance coefficient of up to 1.0 W/m²K, significantly enhancing the building’s energy efficiency. Additionally, the ability to use glazing up to 40 mm thick ensures a high level of interior sound insulation.


AEV test results confirm the excellent properties of water tightness, air tightness, and wind load resistance. This window system provides the highest level of protection against adverse weather conditions.


The window can accommodate hardware with concealed hinges and hidden handles, further emphasizing its modern and minimalist appearance.

  • Exterior cross-section of only 66 mm


  • Glass can constitute up to 85% of the window surface


  • Achieved a uniform and aesthetically pleasing facade with a hidden sash


  • Thermal transmittance coefficient up to 1.0 W/m²K


  • High level of sound insulation with glazing thickness up to 40 mm


  • Excellent water tightness, air tightness, and wind load resistance


  • Protection against adverse weather conditions


  • Capability for concealed hinge hardware and hidden handles
Uw ≥ 0.81 (W/m²K)
Rw = 46 dB
Air permeability: (EN 12207): CLASS 4
Water tightness: (EN 12208): CLASS E1650
Wind load resistance: (EN 12210): CLASS C5
Maximum sash dimensions: L 1300mm, H 2400mm
Maximum sash weight: 160 kg