Infinity from Marvin Blog
Close-up on ultrex fiberglass window
12 JANUARY 2023

Why Choose Ultrex® Fiberglass for your Windows and Doors?

Wood? Vinyl? Fiberglass? How do you choose the best material for your new windows? As we shared in our Fiberglass vs Wood Windows blog, choosing the right material for your windows is one of most important decisions you’ll make during your replacement project. With so many options, it can be challenging.

With strength, durability, and beauty in mind, we created a superior window material to bring new life to your home – Ultrex® fiberglass. Let’s talk about what makes Ultrex fiberglass the best option for your home.

What is Ultrex Fiberglass?

Manufactured by Marvin Windows and Doors, Ultrex is a custom reinforced fiberglass composite used to create the sash and frame components from which Infinity windows and doors are made. Ultrex is engineered to have superior material properties and outperforms and outlasts the competition in the critical categories of strength, stability, and durability.

When developing Ultrex, the challenge was to capitalize on the strength of fiberglass while maintaining the ability to create complex shapes and a slim profile. Essentially, it’s creating the beefiness without the bulkiness – maximizing your views without sacrificing strength. The result is the best replacement window material available.

Internal view of ultrex fiberglass window frame

Strength of Ultrex

Compared to other materials, Ultrex is the strongest framing material available for replacement windows. In terms of tensile strength, which measures the breaking point of a material, Ultrex fiberglass is comparable to low carbon steel. Our superior fiberglass material resists breaking under pressure, so you’ll never have to worry about how your Infinity products will hold up over time.

Alongside the superior tensile strength of Ultrex, it also performs equally well in terms of flexural modulus strength. Unlike tensile strength, flexural modulus strength is a measure of a material's ability to bend. When measuring the flexural modulus strength of Ultrex to other materials, it is 8 times stronger than vinyl and 3 times stronger than Fibrex®. Due to the superior strength in both measures, Infinity windows and doors stay straight and square over time to provide years of dependable operation and performance.

Typically, strength requires mass. However, the superior strength of Ultrex fiberglass allows Infinity sash and frame components to be manufactured in narrower shapes and profiles. Other replacement window materials that have inferior strength require reinforcement, making the windows bigger and bulkier. Because of Ultrex’s strength, we use less of it in our window sash and frame assemblies. This means you get more daylight and better views through Infinity windows.

Strength comparison of ultrex fiberglass compared to vinyl

Stability of Ultrex

In addition to strength, a key attribute of Infinity’s Ultrex is stability. Window operation and performance should never depend on things like the weather, temperature, size of the window, or age of the window. However, many replacement windows are influenced greatly by those factors. In a world that fluctuates, Ultrex can be trusted to be a constant performer. Ultrex is engineered to have the lowest thermal expansion and heat deflection properties of all standard replacement window materials.

Unlike other replacement materials such as vinyl, Ultrex fiberglass expands and contracts at nearly the same rate as glass. Constant expansion and contraction can gradually break down windows and doors, causing poor operation, leaky seals, and a loss of structural integrity. The stability of Ultrex delivers trust and peace of mind that your windows will provide dependable operation and performance.

Because Ultrex holds its shape, the design of Infinity windows incorporates pleasing shapes and profiles that give the windows traditional character and appearances. These are features that most vinyl and vinyl/wood composite windows can’t deliver, simply because the material will not allow them to. Because of the shape-shifting and material deformation, they must keep their profiles and details generic and simple so it will be less noticeable when the material moves. Ultrex eliminates having to compromise traditional details to compensate for inferior materials. Infinity windows are designed to look like traditional wood windows without the maintenance of real wood windows

Ultrex fiberglass expansion compared to vinyl

Durability of Ultrex

Infinity’s Ultrex fiberglass is also durable. Windows made from Ultrex are not only built to last, they’re built to last a lifetime. The superior fiberglass material resists rot, warp, or dent and UV degradation longer than any other material in the window replacement industry. Ultrex stands up to the elements and is essentially unaffected by wind, rain, snow, or hail. Best of all, Ultrex fiberglass requires virtually no maintenance other than periodic cleaning and is covered by Infinity’s Limited Lifetime Warranty.

Ultrex Fiberglass impact resistance

Beauty that Lasts

A superior material deserves a superior finish, and Infinity’s mechanically bonded acrylic finish delivers performance and beauty. This unique acrylic finish provides superior resistance to scratching, cracking, chipping, and UV degradation – even on dark colors. Although the finish does not require painting or refinishing, it is possible

Ultrex Fiberglass quality finish

Strength, stability, and durability. Add beauty that lasts a lifetime, and it’s clear Infinity’s Ultrex is the right choice for your home. The best products are made from the best materials, that’s why replacement windows and doors from Infinity are Built for Life®.

Interested in learning more? Connect with a local Infinity partner to get your questions answered today.


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