Infinity from Marvin Fiberglass Replacement Windows in Green Bay and Appleton, WI
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Marvin Ultrex® Fiberglass Windows

Infinity® Replacement windows and doors are constructed with Ultrex Fiberglass. This pultruded fiberglass is superior to other window materials due to its unmatched strength and durability. Ultrex fiberglass makes infinity windows basically maintenance free.


What makes Infinity® Windows different from other windows? These replacement windows are made from Ultrex fiberglass – a pultruded fiberglass material superior to any other window material. Below is a step by step process of how the windows are created. From forming and curing, and all the way to cutting, these steps create an incredibly durable material to outlast and outperform other window materials. Best of all, since the windows are made with such care, Infinity windows are virtually maintenance free!

Ultrex Window Pultrusion Process

Clearly, these products are made with integrity, and there a several advantages to the Ultrex fiberglass windows as well. The base material of these windows is silica sand; which is natural and abundant. The windows will be easy to operate for the entirety of their duration due to low expansion. Strength keeps the windows square and true. Having a narrow profile allows for more visible glass area for a breathtaking view. Low risk of seal failures and air leakage because of the long-term stability of these windows. Patented acrylic finish is up to 3x thicker than competitors. These means increased resistance to discoloring, scratching, and denting.

Ultrex is as strong as low carbon steel and 8x stronger than vinyl. So strong in fact, that it must be cut with diamond-edge blades. This superior strength of Ultrex windows translates into increased stability, continued ease of operation, minimal maintenance, and optimal performance.

View from vinyl windowView from Ultrex Window

See more of life’s precious moments, with Infinity replacement windows


Ultrex is made to be highly weather resistant, making it perfect for Wisconsin’s wide range of weather conditions. From sub-zero temperatures to sweltering heat, Marvin infinity windows will keep your home insulated.

Ultrex windows have some of the lowest thermal expansion rates on the market today. This allows them to remain weathertight where other windows would run the risk of air leakage and or seal failure. Below is a graph illustrating the Ultrex expansion rate compared to other window materials.

Window Expansion Rate Graph

Ultrex windows also remain easy to operate over the years due to this low expansion rate. Other windows tend to stick and become hard to open after several years of expanding and contracting.

Looking for windows that require little to no maintenance? Look no further, Ultrex windows are the best option for you. This material resists discoloring, rotting, warping, corrosion, and denting. Save the paint and keep your hands clean, because you shouldn’t have to sand, scrape, or paint this windows!


We will let you decide, which one of these windows would look better on your home? Vinyl windows will leave you feeling rather unsure about your purchase. Give your home the face-lift it deserves with beautiful and modern Infinity windows that have clean mechanically-bonded corners and narrow profiles that maximize your view.

Infinity Window Detail Appearance Vinyl Window Detail Appearance

Infinity                      Vinyl Competitor

Why wait? – Get an in-home quote on Infinity replacement windows today!

Windows Of Wisconsin is proud to provide Infinity replacement windows in Green Bay, Appleton, and the surrounding areas. If you own a home in Brown County or the Fox Valley, please give us a call or fill out a contact form here, and we will reach out to you shortly.

If you live elsewhere, please visit to find a dealer nearest you.

Here at Windows Of Wisconsin, we like to provide our customers with the best possible window options. Don’t just take our word that Infinity windows are the best on the market, listen to what our customers have to say about them:

“We love our new windows. They are beautiful and we can already tell they’re going to make a difference in our electric bill. Very proud of them.”


“We compared prices and quality of windows and we found Marvin to fit our specific needs. After only 3 months our level billing for electric was reduced by $11.00/mo. Our home is approximately 1400 sq. ft. We are very satisfied with the quality, looks and installation of the windows. Installation was done expertly and clean up was excellent. The installers were very efficient, friendly and prompt. The salesman did a Great job in promoting your product and answered all our questions to our satisfaction. We are more than happy to recommend Marvin windows to our friends and neighbors.”


“We have had positive experiences with Windows of Wisconsin.  Back in 2006 we purchased Infinity by Marvin Windows and have been very happy with the product along with the service.  The few times we had a hiccup, Carl was quick to come or send someone to our home to make the repair. They are very professional and knowledgeable and we would highly recommend them to others.

As far as the Infinity by Marvin Windows, we are most pleased as we were able to match the stain to our existing trim and they do not look like replacement windows.”

–Steve & Kim Walters

Windows of Wisconsin is a Member of the Brown County Home Builders Association
Windows of Wisconsin in Green Bay and the Fox Cities is a Top 500 Remodeler
Windows of Wisconsin is Better Business Bureau Accredited with an A+ Rating