For Passivhaus and net-zero projects, the window is where performance is won or lost. GlasFëns is built for exactly this.

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Based on proven European systems and fitted with German hardware, our fiberglass and thermally broken aluminum windows are engineered for the thermal demands of passive buildings. Our flagship fiberglass and vacuum-glass system reaches a whole-window U-value of 0.045 (R-22), with Passivhaus-certified assemblies available across the range. Every unit is built to deliver on the metrics that matter: low whole-window U-values, minimal thermal bridging, exceptional airtightness, and a fail-resistant insulated glass seal engineered for long-term durability.

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Beyond the numbers, our systems give designers room to work, with narrow frames for higher glazing ratios and better solar gain, concealed hardware, and our advanced vacuum-glass IGU as standard. Conventional triple and double glazing are available where a project calls for it. From single-family passive homes to certified multi-family and prefab developments, GlasFëns helps you close the envelope and hit your target, approaching zero.