Ultrex Fiberglass windows from Elevate Collection

Your Guide to Fiberglass Windows

Are you a homeowner looking for a sturdy and energy-efficient window upgrade? Say hello to fiberglass windows! In this handy guide, we’ll explore why fiberglass windows are a must-have for your home. 

First, let’s discuss a common pain point that we want to address. Options, yes options. there are so many window and door options available in the marketplace. And unless you’re a window geek, you might find yourself fatigued from research and frustrated by all the contradicting information you are reading. It’s simply overwhelming. Unfortunately, homeowners frequently end up either choosing the least expensive option or relying on others to make the decision on their behalf. Our goal today is to equip you with the fundamental information necessary to make a well-informed decision about your window and door investment.

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Ultrex Fiberglass Windows: The Ideal Pick for Style, Performance, and Cost

In a hurry? Here’s the Reader’s Digest version: Ultrex Fiberglass windows are the way to go when it comes to finding a combination of style, performance, and affordability. These windows are stronger than vinyl, less costly than aluminum-clad wood windows, and are known for their top-notch performance and aesthetics. For a more detailed discussion, keep reading and let’s geek out together!


Marvin Elevate Double-hung window and French Sliding Patio Door Marvin Elevate Double-hung Window and French Sliding Patio Door.

Let’s begin with Why Materials Matter!

Material matters more than you realize. Window frames serve as the backbone of your window, providing support for the glass panes and securing the window in your home’s wall. Though often overlooked, the material used for your window frames is equally – if not more – important than the glass itself. This is because the frame material has a significant impact on the window’s energy efficiency, durability, overall performance, and maintenance. In this regard, Ultrex fiberglass stands out from its competitors. Let’s delve deeper into why it outperforms other materials.

What is Ultrex Fiberglass?

Ultrex is a pultruded fiberglass product patented by Marvin. Marvin creates Ultrex by saturating strong glass cables with specialty compounded resins, pulling the glass cables through a heated dye and cutting them with diamond-edge blades. The result? Fiberglass windows that are stronger and more maintenance-free than vinyl, wood, or any other window material on the market.

Ultrex Fiberglass construction Ultrex Fiberglass construction


Let’s look at the valuable benefits of Ultrex fiberglass and how the strength of this material stacks up against vinyl and vinyl/wood composite windows:


Benefits of Fiberglass windows and Doors
  • Endures harsh weather conditions and climates with minimal wear and tear over time
  • Virtually maintenance free
  • Provides exceptional structural strength, ensuring windows and doors open and close easily for years to come
  • Does not expand and contract with dramatic changes in temperature, making the product resistant to leaks, seal failures, and stress cracks
  • When combined with energy-efficient glass options, fiberglass keeps the indoors comfortable regardless of what’s happening outdoors


It’s important to steer clear of fiberglass that contains high concentrations of plastics, vinyl, sawdust, and wood fillers. The finest fiberglass used in window construction is composed of only fiberglass fibers and resins. The results:  stronger frames that do not become brittle or sag in extreme temperatures.


Ultrex fiberglass vs vinyl

Ultrex Fiberglass Windows vs Vinyl

Vinyl can warp and shift under everyday conditions — potentially making vinyl windows difficult to open and close and affecting their all-around performance. Ultrex resists sticking, swelling, and warping, so they will continue to easily open and close. Fiberglass is also more fade-resistant and able to handle high temperatures, which is why it is available in darker colors.


Marvin Ebony Exterior Windows Marvin’s proprietary acrylic finish is 3X thicker than the competition’s, and it was the first in the industry to achieve AAMA 624 verification. No sanding, scraping, or painting required. Marvin’s finish resists scratching and denting, and it performs so well that we offer dark colors without fear of UV degradation or fading.

Ultrex Fiberglass Windows vs Fibrex

Contrary to popular belief, Andersen Fibrex® is not fiberglass, but is instead a composite material made up of 40% wood and 60% plastic. It is a thermoplastic material, which simply means it has the potential to change shape when exposed to extreme temperatures. Ultrex is a thermoset material crafted through a chemical process that alters the product at the molecular level. Therefore, Ultrex won’t soften or melt when exposed to environmental temperatures, explaining much of the material’s excellent performance.


Ultrex 8x stronger than vinyl


To sum it up, fiberglass windows are a smart choice and investment for homeowners. Upgrade your home’s appearance with Ultrex Fiberglass and enjoy a 10% discount until December 15th. Contact JB Sash today for a free quote and elevate your style!

Explore products that use Ultrex Fiberglass.