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Vinyl vs. Ultrex Fiberglass from Infinity from Marvin

At Quality Window & Door, we carry top window and door products from today’s best manufacturers. Infinity from Marvin replacement windows are among our most popular products. The entire line features windows made of Ultrex fiberglass, a pultruded fiberglass material that sets Ultrex apart from other windows available today.

When you have the choice between ordinary vinyl windows and Infinity from Marvin replacement windows made from Ultrex fiberglass, the decision is obvious. Here are the characteristics that set Ultrex apart.


Ultrex fiberglass goes through a meticulous manufacturing process. Every step of the way – from saturating sturdy glass cables in compounded resins to pulling these cables through a heated die – helps to create a remarkably strong material that outlasts the competition. In fact, Ultrex fiberglass is eight times stronger than vinyl. It’s so tough that a diamond-edge blade is needed to cut it during the manufacturing process.

Expanded View

You might wonder – why does material strength matter? All a window does is sit in a frame and support a few panes of glass. However, it’s thanks to the superior strength of Ultrex that narrower window frame profiles are possible. This provides more daylight streaming in and better views looking out.

Low Expansion & Contraction Rates

Changes in humidity and temperature cause various materials to expand and contract at different rates. Vinyl’s expansion and contraction rate is about 833% greater than glass. Such drastic fluctuations may cause the window seal to fail after just a few years.

On the other hand, Ultrex expands and contracts at virtually the same rate as glass, primarily because it’s made out of a similar material, fiberglass. This helps Infinity from Marvin windows remain tightly sealed after many years in use.


According to a window lifecycle assessment performed by the University of British Columbia, fiberglass windows have an estimated 38% longer useful lifespan than vinyl. In addition to its inherent durability, Ultrex also features a thick exterior acrylic finish to help it withstand temperature changes, direct sunlight, harsh wind and rain, and even salty coastal conditions.


The makers of Infinity from Marvin windows understand that wood is the most aesthetically pleasing window material of all. Ultrex windows are designed to mimic this appearance with intricate wood grain profiles. You can even stain the interior frame to match the woodwork in your home! This creates an impressive simulated wood look without any maintenance. Indeed, Ultrex windows never require sanding, painting, or re-staining to retain their beauty for decades to come.


The Ultrex manufacturing process consumes 39% less energy than it takes to produce vinyl windows. Then, at the end of their useful lifespan, Ultrex fiberglass windows are 100% recyclable.

While in use, Ultrex fiberglass windows help reduce your energy bills thanks to low conductivity and air infiltration rates. Plus, when paired with low-E glass, Ultrex can block UV radiation to minimize heat gain without compromising visible light.

Install Infinity from Martin Ultrex Fiberglass Windows in MD, DC & VA

Everything about Ultrex fiberglass makes it superior to vinyl windows. For an investment you can count on for years to come, make Infinity from Martin your next window replacement choice. Then, choose Quality Window & Door as your professional installer. Our team is knowledgeable and experienced with performing window installations in the Maryland, DC, and Virginia areas.

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Feel free to visit one of our local showrooms in Maryland and Northern Virginia to see Ultrex fiberglass windows in action and receive answers to all your questions. We’re also happy to schedule a free in-home consultation when you’re ready to get your project started.

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