Our product range embodies the essence of minimalist design by combining simplicity with functionality and comfort. Our minimal windows®4+ is characterized by the integration of triple-glazed premium windows, available as sliding or fixed units, perfect for creating expansive glass façades. These windows not only flood interiors with natural light, but also open up unobstructed views of nature and seamlessly merge indoor and outdoor areas.

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Architects can unleash their creativity with our products, as the 4+ enables oversized glass surfaces with heights of up to 6 meters and a weight of up to 1,000 kg per sash. In line with the latest energy-efficient building standards, our solutions are suitable for low-energy and passive houses.

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In combination with high-quality insulating glass, our 4+ system enables Uw values of ≥ 0.70 W/m²K and therefore considerable energy savings. In addition, our aluminum frames are designed to withstand strong wind loads while maintaining their slimline elevations of just 26 to 34mm. The minimalist frame profiles integrate seamlessly into floors, ceilings or walls.

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At Keller minimal windows, we offer architects, contractors and homeowners a wide range of design options. From mullion-free inner or outer corners to pivot units and all-glass corners, our products offer endless possibilities. For those looking for an even more seamless transition between interior and exterior spaces, our sliding units can disappear into specially designed wall pockets to create unrestricted views and unparalleled aesthetics.