Fibrex vs Fiberglass Windows

Fibrex vs Fiberglass Windows

Windows come in a variety of materials to suit your needs, including Fibrex and fiberglass. Both of these types of windows are becoming more popular, and they’re worth considering for a new home or an upgrade to your existing home. Here’s some more information about the differences between Fibrex and fiberglass windows.

Fibrex vs Fiberglass Windows

When you compare the pros and cons of Fibrex and fiberglass windows, you should consider their construction, durability, energy efficiency, and cost. You should also think about how long getting your new window and having it installed will take. If there’s a waiting list for your first choice, you may need to have another type of window installed, especially if you’re replacing a broken window. How the new window will look with the rest of your home is important as well.


Fibrex windows contain 60% thermoplastic polymer, also called plastic or vinyl, and 40% wood fibers. Andersen created it when they were trying to find new ways to recycle leftover sawdust and scraps of other raw materials. Most of the materials used to make these windows are recycled.

Fiberglass is a type of plastic that uses thin strands of glass to reinforce it. Fiberglass windows are made in an automated process called pultrusion. Lengths of fiberglass are bathed in resin, covered with more fiberglass, and placed in a heated die to harden the resin. Then, they’re cut and fitted with nylon-reinforced corner blocks for strong joints between window parts.

Aesthetics and Curb Appeal

Fibrex and fiberglass windows are both available in a wide variety of sizes, including custom sizes. However, Fibrex windows come in more colors and shapes. You can get Fibrex® windows that resemble pine, maple, or oak. You can repaint or stain both types of windows if you decide your home needs a new look. With Fibrex®, the color penetrates the entire frame, making painting unnecessary in most circumstances. While Fibrex® usually looks like wood, fiberglass looks painted, and it can be shiny or matte.


Similar to fiberglass, Fibrex is 700 times stronger than aluminum and about three times stronger than vinyl. The repurposed wood inside it contributes to its strength, and the plastic or vinyl makes it easy to maintain. Warranty options include 20 years for the glass and 10 years for the frames, and Fibrex windows should last for about 35 years. Fiberglass windows usually last for the same amount of time.

Both types of windows are resistant to peeling, warping, corrosion, and hot or cold temperatures. Fiberglass can fade over time from exposure to UV light, but you can simply repaint it for a brand new look. The seals around the glass on fiberglass windows stay in place better than Fibrex and other materials because the fiberglass and glass expand and contract after temperature changes at the same rate. Minor scratches in both types of material are possible but rare.


With Fibrex or fiberglass windows, you won’t have to worry much about maintenance. If you choose to paint your windows, you’ll need to repaint them occasionally. Otherwise, you only have to wipe off the frames and glass when they get dirty. Use a soft cloth and window cleaner.

Energy Efficiency

Fibrex and fiberglass windows are both extremely energy-efficient. Fiberglass is a better insulator, but Fibrex is more efficient than most other window materials. If you notice a draft or a gap in either window type’s insulation, have it repaired immediately to keep your power bills low.


Fibrex windows can cost from around $450 to more than $1,600. Fiberglass windows usually cost about $400 to $1,200. For many people, Fibrex windows are worth the additional cost because they’re more durable and they come in more colors. If you want to save money, you can choose less expensive vinyl or wood windows. However, they won’t last as long or increase the value of your home like Fibrex or fiberglass.


Andersen introduced Fibrex windows in 1992, and they’re available only from Andersen franchises and dealers. Fiberglass windows are available from a variety of vendors, including Marvin, Milgard, and Pella. Pella's Fiberglass Impervia windows are engineered for lasting durability, and they use a long-lasting, attractive powder coating. The Alpen Zenith Series is made in the United States, and you can choose a standard or custom size. Andersen offers fiberglass-cladded wood as part of their A-Series, and these windows are part of their Architectural Collection.

Which type of window is best for your home depends on the color and style you’re looking for, your budget, and the companies that offer windows in your area. If you want to replace the windows in your North Texas home, contact us at Brennan Enterprises, Inc. for a free consultation. We can help you choose and install windows that you and your family will love. We’re open from 9 a.m. to 5 p.m. on weekdays.


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