Fiberglass Fenestration: A Durable, Sustainable, and Economic Alternative for Windows and Doors

By combining the benefits of aluminum, vinyl, and wood windows, fiberglass composites provide aesthetics and longevity for any environmental condition.
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Advertorial course provided by Pella® Windows & Doors
Barbara A. Nadel, FAIA

Window composite configurations can often be factory-assembled, which generally accelerates installation at the job site.

Sliding windows provide a range of design, ventilation, and egress solutions.
Photo: Courtesy of Pella Windows

Benefits of Fiberglass Compared to Aluminum Storefront Fiberglass composite fixed frame windows offer design flexibility, energy efficiency and an alternative to aluminum storefront. Advantages are summarized as follows:


  • Fiberglass composite offers a similar appearance and many performance advantages, and is an economic alternative to aluminum

Durability and Strength

  • Fiberglass composite is the strongest, most durable material available in windows and doors
  • Resistant to dents and scratches
  • Not prone to corrosion in seacoast and harsh environments
  • No thermal break is required, which eliminates the durability issues associated with dry shrinkage of poured urethane thermal breaks common to aluminum windows.

Factory Glazing

  • Offers better quality control
  • Reduces field installation time
  • Allows general contractors to install with their own workforce

Energy Efficiency

  • Lower energy costs
  • U-value of the fiberglass composite frame is 2.4 times better than thermally- broken aluminum
  • Offers greater resistance to condensation
  • Provides superior thermal comfort to occupants seated near windows

Less Thermal Expansion

  • Three times less thermal expansion than aluminum frames, in testing performed in accordance with ASTM testing standards
  • Assures consistent, weathertight seal between frame and glass
  • Provides a frame that expands at the same rate as the glass; no glazing gaskets to maintain because of expansion and shrinkage


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Architectural Record
Originally published in June 2006