Whole-window NFRC Ratings up to R-10 (U-0.10) for fixed windows and R-7 (U-0.14) for operable windows.
Long strand pultruded fiberglass frame.
Super-insulating closed-cell foam in both frame and sash cavities enhances thermal insulation properties.
Industry leading lightweight high-performance ThinGlass (triple and quad-pane).
Certified, proprietary gas retention technology allows us to offer gas-filled windows to customers at high altitude.
Air infiltration rates as low as 0.01 CFM per square foot.
Deeper glass pocket allows for enhanced sound reduction.
As a global leader in ultra energy efficient window, door and glass solutions, all Alpen Zenith Series fiberglass windows and doors are carefully designed to meet the energy efficiency needs of our changing world.
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This specification system has been prepared to assist design professionals in the preparation of project or office master specifications. It follows guidelines established by the construction specifications institute, and therefore maybe used with most master specification systems with minor editing.
INSTALLATION GUIDELINES:
The Zenith Series offers a full lifetime warranty for as long as you own and reside in your building.
Visit Warranty PageAlpen was the first North American window manufacturer to achieve dual certification from both PHIUS and PHI. We specialize in high-performance building products, with a focus on energy-efficient windows and doors. Our Passive House-certified products help architects, general contractors, and developers meet or exceed modern energy codes and build climate-responsive buildings.
Zenith is an energy-efficient fiberglass window with North American outswing functionality, achieving up to R-10 rating. Tyrol uses fiber-reinforced uPVC frames with European inward swing functionality, achieving up to R-11. Zenith focuses on fiberglass durability and environmental benefits, while Tyrol highlights European engineering and aesthetic versatility. Both products are energy star certified.
Yes, fiberglass is a highly energy-efficient insulator with low thermal conductivity, helping maintain consistent indoor temperatures. Fiberglass stability prevents air leakage and can accommodate energy-efficient triple or quadruple glazing.
The most energy-efficient windows use advanced frame materials with high thermal resistance. Then they incorporate multi-pane insulated glass units with gas fills between the panes. Finally, precise construction prevents air leakage through gaps.
Fiberglass window manufacturers build products to last 50 years or more. Resistant to warping, rotting, and corrosion, fiberglass withstands harsh weather without deterioration. Its strength and stability maintain window integrity over time, ensuring efficiency and functionality for decades. The Zenith Series includes a full lifetime warranty while you own and reside in your home.
When considering vinyl vs fiberglass windows, fiberglass has a higher material cost than alternatives. It requires complex manufacturing processes like weaving fibers into resin-impregnated fabrics under controlled conditions. Though costlier upfront, fiberglass offers superior durability, thermal efficiency, and design flexibility.