77IW Open-In Window


High performance Open-In Window

Our highest performing window, the 77IW Open-In Window System is ideal for new build and refurbishment developments. The versatility of the system also makes it suitable for use in both high-rise and low-rise buildings. The system has been specifically designed to meet the most demanding British and European performance requirements in terms of thermal, weathering and security.

For optimal design flexibility, the 77IW is available in single or dual colour options, including any RAL colour and anodised finishes.


Modern contemporary styles and a wide variety configurations delivering high levels of thermal performance through incorporating technologies such as high performance polyamides, insulated centre seals and profile foam insertions. The 77IW system also fully integrates with our curtain walling and door systems.

Technical data
U value W/m²K 0.8-1.2 W/m²K
Air tightness (Pa) Class 4 (600Pa)
Water tightness (Pa) Class E1050 (1200Pa)
Wind load (Pa) Class C5 (2000Pa)