Residential

Zenith Series Doors

Zenith Series Doors
Zenith Series Doors
Zenith Series Doors

Designed to seamlessly connect you to the outdoors, these doors offer expansive views, abundant natural light, and modern aesthetics. With sleek profiles and cutting-edge engineering, Zenith Sliding Doors provide unobstructed views, energy efficiency, and lasting durability—all with smooth, effortless operation and enhanced security.

  • Achieves thermal performance up to R-7.1
  • Available in several popular configurations and colors, including black
  • Heavy-duty rollers and advanced track systems for a smoother glide
  • Proudly designed, developed and manufactured in the USA
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Design Options

Models
Selected:
Grandline
Description: Built for size without compromising style or performance. Featuring a bolder frame and larger maximum sizes – perfect for high wind loads
Description: Traditional sliding glass door – but better. Sleek, narrow framing allows for expansive views.
Configurations
Selected:
4 Panel Door (OXXO)
4 Panel Door (OXXO)
2 Panel Door (OX / XO)
3 Panel Door (OOX / XOO)
3 Panel With Center Vent (OXO)
Note: Transoms and Sidelights also available*
Finish
Selected:
Midnight Black
Midnight Black
Classic Collection
Pure white
Classic Collection
Umber Bronze
Classic Collection
Bronze
Signature Collection
Alpine Ivory
Signature Collection
Sand Dune
Signature Collection
Riverstone
Signature Collection
Boulder Grey
Signature Collection
Silver Mist
Signature Collection
Bison Brown
Signature Collection
Red Canyon
Signature Collection
Pine
Signature Collection
Stormy Sky
Trend Collection
Verde Valley
Trend Collection
Deep Water
Trend Collection
Note: Colors are representative and can vary based on a computer screen.
Request color cards or painted fiberglass samples.Order samples here.
Handles
Selected:
Verona Handle
White
Black
Beige
Sandstone
Satin Nickel
Oil Rubbed Bronze
White
Black
Beige
Sandstone
Satin Nickel
Oil Rubbed Bronze
Glass
Selected:
Triple-pane

Thermal performance up to R-7.1 

Warp-resistant fiberglass frames provide superior strength and thermal performance.

Industry-leading ThinGlass technology in triple and quad-pane for maximum energy efficiency.

Multi-point locks offer maximum security and contribute to a smoother operation.

Advanced gas retention system allows for availability in high altitudes.

Grandline Model withstands higher-than-average wind loads – ideal for high wind areas. 

Air infiltration rates as low as 0.01 CFM per square foot.

Luxury, smooth-glide rollers meet AAMA 906 certification standards.

Integrated screen track ensures proper screen alignment and enhances the door’s seal.

Grandline Model features concealed, inner corner key that offer enhanced aesthetic appeal, increased durability, and improved security.

Triple and quad pane glass enhances whole door sound attenuation for a quieter indoor refuge.  

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.

Discover our Product Catalog for more information.

Grandline Product Info Sheet
Narrowline Product Info Sheet

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.

3-Part Guide Specification
[DOWNLOAD]

Details & CAD Files

Grandline Sliding Glass Door
Narrowline Sliding Glass Door

INSTALLATION GUIDELINES:

Contact us (info@thinkalpen.com) for installation instructions

The Zenith Series offers a full lifetime warranty for as long as you own and reside in your home.

Visit Warranty Page
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Why Choose Zenith?

Long-Lasting  Durability

Long-Lasting  Durability

  • Long-strand pultruded fiberglass makes Zenith doors stronger than aluminum and more durable than wood and vinyl. An Inline Fiberglass lifecycle assessment reveals that fiberglass offers a 38% longer useful life expectancy than vinyl. 
  • Zenith’s fiberglass withstands extreme temperatures and high wind loads, expanding and contracting 800% less than vinyl. This reduces air leaks and maintains energy efficiency over years of temperature changes, offering worry-free durability.

Superior Water and Air Resistance

Superior Water and Air Resistance

Zenith doors are built to withstand severe weather conditions and hold the AAMA certification for exceptional wind, water, and air resistance. Advanced sealing technology ensures protection against water damage and air infiltration as low as 0.01 CFM per square foot, making your home resilient against the elements.

Architectural Freedom

Architectural  Freedom

Superior strength-to-weight ratios make the Zenith series an ideal option for large openings. Lightweight glazing solutions and low-profile frames enable high glass-to-frame ratios, allowing more natural light. Custom sizes, shapes, hardware options, and colors seamlessly integrate with your design plans, offering architectural freedom.

Enhanced Peace and Quiet

Enhanced Peace and Quiet

Zenith doors provide significant noise reduction with sound attenuation performance up to STC 39, creating a peaceful and ultra-quiet indoor environment.

Healthy and Safe Living Spaces

Healthy and Safe Living Spaces

  • Zenith is the first North American window and door certified under the Living Building Challenge Declare label "Red List Approved". This means it does not contain harmful chemicals. High-quality, low-VOC paints minimize off-gassing, contributing to superior indoor air quality.
  • Triple gasket seals and insulating properties prevent mold and mildew growth, maintaining a healthy living environment.
  • Forced entry resistance tests assess windows and doors to see how well they restrain, delay, or frustrate forced entry. 

Future-Proof Your  Home

Future-Proof Your  Home

  • Zenith windows and doors are a long-term investment that adds value to your home. This ensures they meet future building standards, keeping your home's envelope ahead of the curve.

  • High-performance products like Zenith save you money on energy bills. They also give you flexibility for future home upgrades. An efficient building envelope can help optimize modern HVAC solutions such as electric heat pumps. This can help with long-term energy savings and a smaller carbon footprint.

Sustainability
Focused

Sustainability
Focused

Zenith frames are made from environmentally friendly silica, requiring less energy to produce than other materials and significantly reducing greenhouse gas emissions. Our efficient production processes and reduced material usage result in low embodied carbon. Additionally, the enhanced longevity of Zenith doors minimizes their environmental impact throughout their lifecycle.

Affordability without Compromise

Affordability without Compromise

At Alpen, we believe in delivering exceptional value. Our mission is to show that high performance doesn’t require an exorbitant price tag. We aim to make our top-tier windows and doors accessible to a broader audience, ensuring more people can enjoy the benefits of high performance. By expanding our reach, we contribute to a greener, more climate-resilient world.

Ensuring Customer Success

Ensuring Customer Success

  • Investing in Alpen products means gaining our expertise and support for the long term. Our customer success team offers project expertise, technical proficiency, and readily available resources. 
  • Investing in Alpen products means gaining our expertise and support for the long term. Our customer success team offers project expertise, technical proficiency, and readily available resources.   As one of the few American-made passive house-certified window and door providers, we ensure shorter lead times and responsive project timelines, giving you greater control and flexibility for your construction schedule.

Unparalleled Performance and Comfort

Unparalleled Performance and Comfort

Zenith doors exceed Energy Star requirements with NFRC certification up to R-7.1. Its superior U factor, Solar Heat Gain Coefficient, and low air leakage block summer heat, retain winter warmth, and allow abundant natural light, ensuring unmatched comfort and energy efficiency. 

Frequently Asked Questions

What’s the difference between Zenith and Tyrol?

Zenith is an energy-efficient fiberglass window and door series 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.

Are fiberglass windows and doors energy efficient?

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.

What type of doors will be the most energy efficient?

The most energy-efficient doors 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. 

How long do fiberglass doors last?

Fiberglass window and door 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 product 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.

Why do fiberglass doors and windows cost more than alternatives?

When considering vinyl vs fiberglass, 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.

Need More Information?

For custom inquiries or more information.