Renewal by Andersen interior space with a picture window

Resource Article

Fibrex® Composite Material

Learn more about our Andersen-exclusive Fibrex® composite material.

Decades ago, Andersen Corporation set out to do something extraordinary—to redefine the standard for window materials. The result? Fibrex® composite material, a game-changing innovation crafted from the perfect blend of cutting-edge technology and a desire for sustainable design.

Learn more about the history of Fibrex material—how it transformed the home improvement industry, why it’s the gold standard for homeowners, and how it can help reshape your living space. From its science-backed durability to its unmatched beauty and performance, Fibrex material is more than just a window material; it’s an investment in your home’s future.

Reinventing the Window

Innovation has been a hallmark of Andersen Corporation since its founding in 1903. From implementing “mass production” techniques in 1904 (nine years before Henry Ford), to producing the first completely assembled window unit in the industry (1926), to becoming the world’s largest specialized window frame factory in 1929, our guiding principle has always been to “make a product that is different and better.” Each step of the way we have incorporated the latest technologies, fine precision, and high standards in our quest to be better.

In 1992, Andersen perfected composite window technology, and patented Fibrex material. Today, Fibrex material is the practical choice for your new replacement windows.

Renewal by Andersen history from 1904
Innovation has been a hallmark of Andersen Corporation since its founding in 1903.
Close up of Renewal by Andersen black window
A double-hung window made with Fibrex® composite material.
A double-hung window made with Fibrex® composite material.

What Is Fibrex Material?

Fibrex material is made from reclaimed wood fiber and thermoplastic polymer that is fused together and is exclusively produced by Andersen Corporation. This revolutionary substance combines the strength and stability of wood with the low-maintenance features of vinyl.

The innovation behind Fibrex material lies in its very composition. 40% of it is comprised of reclaimed wood fibers, making it as environmentally responsible as it is durable. Designed to outperform traditional materials like wood, vinyl, and aluminum, Fibrex material is the epitome of next-generation engineering tailored for modern homes.

What Makes Fibrex Material Exceptional?

1. Exceptional insulation properties

Durable and reliable, Fibrex material has a low thermal expansion rate, is virtually resistant to rotting, insulates well, and retains its rigidity in temperatures up to 150 degrees. That means it can withstand various seasonal temperature swings across the nation—no matter how cold the winters and how hot the summers.

Recently, we pulled several of our original windows from the home they had been installed in more than two decades ago.* That’s more than 20 years of extreme Minnesota weather—bitter, brutal winters and hot, muggy summers. The result? After all those years of enduring Mother Nature, they passed our battery of performance tests with flying colors. After two decades in a real family home, they still looked brand new, and opened and closed as easily as the day they were installed.**

2. Resistant to decay and mold

With Fibrex composite material, a special polymer formulation surrounds and coats each wood fiber in the manufacturing process, providing exceptional resistance to rot and fungal growth. Renewal by Andersen’s windows, made with Fibrex composite material, never need scraping or painting because they are warranted not to flake, rust, blister, peel, crack, pit, or corrode.***

Because our unique process fuses the versatile color onto the Fibrex® material, it means we can offer long-lasting, low-maintenance colors—including dark exterior colors like black, that are not typically found with vinyl windows.

3. A sustainable choice

Fibrex material is made from reclaimed wood fibers. Our products have a long lifecycle, backed by the nation’s best warranty.**** Choosing products that are built to last is one of the ways homeowners can limit landfill waste.

4. Stable and predictable

Fibrex composite material is twice as stable and rigid as vinyl. Wood’s average stiffness is higher, but it’s less predictable than Fibrex composite material because of wood’s natural variations like grain, knots, and moisture content. Fibrex composite material is strong, so frames can be made narrower than with other framing materials.

Narrower frames mean more glass, and more view. Fibrex composite material can be made into any style of window—including curved specialty windows—and in colors to complement every home.

How Does Fibrex Material Compare?

When compared to traditional materials like wood or vinyl, Fibrex material comes out ahead every time. Here’s how it stands apart:

Wood: While wood offers classic beauty, it requires constant upkeep and is vulnerable to rot and mold. Fibrex material retains that authentic charm without the labor-intensive care.

Vinyl: Vinyl may be affordable but can lack durability, warping easily in heat. Fibrex material is twice as strong and provides a premium finish.

Aluminum: Aluminum conducts heat and isn’t energy efficient. Fibrex material, by contrast, insulates about 700 times better than aluminum, keeping homes more insulated and reduces energy loss.

A Worthy Home Investment

Home improvement can and should take into consideration aspects such as beauty, durability, sustainability. Andersen’s relentless innovation has gifted homeowners a material that doesn’t just live up to its claims but consistently exceeds expectations and leads the industry.

Fibrex material gives you a chance to transform not only your home’s aesthetic but its efficiency too. Whether you’re upgrading for practical reasons or beautifying your space, Fibrex material has the potential to make every room brighter, cozier, and more sustainable.

Are you ready to transform your living space? Contact Renewal by Andersen today to learn how Fibrex material can bring durability, beauty, and energy efficiency to your home. Our expert team is standing by to guide you every step of the way.



*Based on testing of 10 double-hung units 20 years after installation.

**Testing per ASTM E2068

***See Renewal by Andersen® Products and Installation Transferable Limited Warranty for details.

**** It is the only warranty among top selling window companies that meets all of the following requirements: easy to understand terms, unrestricted transferability, installation coverage, labor coverage, geographically unrestricted, coverage for exterior color, insect screens and hardware, and no maintenance requirement. Visit renewalbyandersen.com/nationsbest for details.

Our Hassle-Free Process

Meet with your design consultant in-home or virtually to design a replacement solution that works for you. You’ll get options that fit your home, your timeline, and your bottom line.

Step 1

Design Consultation

Meet with your design consultant in-home or virtually to design a replacement solution that works for you. You’ll get options that fit your home, your timeline, and your bottom line.
Your project technician will assess your home, take detailed window and framing measurements, and answer any last-minute questions before sending in the order for custom-built windows.

Step 2

Measure and Manufacture

Your project technician will assess your home, take detailed window and framing measurements, and answer any last-minute questions before sending in the order for custom-built windows. 
Our installers treat your home as if it were their own. They come prepared with a “rolling workshop,” take time to answer any of your questions, and clean up thoroughly when done.

Step 3

Installation

Our installers treat your home as if it were their own. They come prepared with a “rolling workshop,” take time to answer any of your questions, and clean up thoroughly when done.
A robust limited warranty is backed by a commitment to making sure your windows function as expected. We will be here for you today, tomorrow, and decades down the road.

Step 4

Customer Care

A robust limited warranty is backed by a commitment to making sure your windows function as expected. We will be here for you today, tomorrow, and decades down the road.