Our product range embodies the essence of minimalist design, combining simplicity with functionality and comfort. The minimal windows®4+ system features premium triple-glazed windows, available as sliding or fixed units, perfect for creating large glass façades. These windows not only fill interior spaces with natural light but also open up unobstructed views of nature, seamlessly connecting indoor and outdoor environments.

Architects can unleash their creativity with our products, as the 4+ system allows for oversized glass surfaces up to 6 meters in height and 1,000 kg per sash. In line with the latest standards for energy-efficient buildings, our solutions are suitable for low-energy and passive houses.

In combination with high-quality insulating glass, our 4+ system achieves Uw values of ≥ 0.70 W/m²K, resulting in significant energy savings. Moreover, our aluminium frames are engineered to withstand strong wind loads while maintaining slim elevations of only 26 to 34 mm in width. The minimalist frame profiles integrate seamlessly into floors, ceilings, or walls.

At Keller minimal windows, we offer architects, contractors, and homeowners a wide range of design options. From post-free corners — internal or external — to pivoting units and fully glazed corners, our products provide limitless possibilities. For those seeking an even more seamless transition between indoor and outdoor spaces, our sliding units can be concealed within specially designed wall pockets, creating uninterrupted views and unparalleled aesthetics.