Infinity from Marvin Blog
Interior Fiberglass Window from Infinity from Marvin
06 MAY 2022

Vinyl vs Fiberglass Replacement Windows

When replacing your windows and doors, choosing the right material plays a key role in the process. With all the material options available, this process can seem overwhelming. At Infinity from Marvin, we are here to help guide you through this replacement journey so you can feel confident making the best decision for your home.

Two of the most popular window replacement materials in today’s market are vinyl and fiberglass. While both options will provide a fresh look to your home, there are some key differences when deciding which option is best for your replacement project.

Vinyl windows

Since the 1970s, vinyl windows were created to provide homeowners with a lower cost alternative to wood windows. Known for its claims of being a low maintenance option to wood, vinyl windows typically are not as strong as other window materials. To support the glass, vinyl windows tend to have a larger frame and sash profile — meaning less daylight into your house and obstructed views.

Windows are exposed to every element mother nature has to offer. Many places see dramatic temperature swings throughout the year — sometimes throughout the day. Because vinyl windows are not as strong, they present other challenges. Some of the biggest issues include expanding, contracting, denting, and warping. When a window expands and contracts, the window can fall out of square making it more difficult to open or close. When a window is not sitting in the opening properly, other issues with structural and thermal performance can occur. Because of these issues, many homeowners find themselves having to replace their windows more frequently.

Fiberglass windows

When comparing window and door materials, fiberglass is another very popular option. Because fiberglass windows are stronger than vinyl, they resist expanding, contracting, denting or warping at a greater rate. Fiberglass windows are a great option due to the fact they require very little maintenance, are more energy-efficient than vinyl windows and cost less than wood windows.

From this standpoint, Infinity from Marvin wanted to design a superior fiberglass material that outperforms and outlasts all other window replacement materials — Ultrex®.

Child standing on Ultrex Fiberglass Window and Vinyl window

Infinity from Marvin’s Ultrex fiberglass 

While fiberglass is a superior material to vinyl, not all fiberglass windows are the same. Infinity from Marvin’s Ultrex fiberglass windows are truly unique. Ultrex fiberglass is a pultruded fiberglass composite pioneered by Marvin. Ultrex sets Infinity windows and doors apart from the competition with the ability to build larger units.

By utilizing a pultruded fiberglass composite, Infinity from Marvin was able to make Ultrex 8x stronger than vinyl and 3x stronger than wood/vinyl composites — supporting up to 34,000 pounds. This allows for narrower frames, bigger views, and additional sunlight.

Ultrex fiberglass window vs vinyl window

Because fiberglass is a thermally stable product, it expands 87% less than vinyl windows. Ultrex's low thermal expansion rate means our windows and doors stay tight and true even after extreme temperature swings. By expanding and contracting at nearly the same rate as glass, Infinity windows made with Ultrex are more resistant to leaks and seal failures so you can enjoy your windows for years to come.

Diagram of window material

The strength of fiberglass windows is important, but Ultrex fiberglass has more than strength — it adds beauty. Infinity's proprietary acrylic finish is 3x thicker and smoother than the competition. Our finish resists scratching and denting and performs so well that we offer dark colors without fear of UV degradation or fading.

Window material comparison

At Infinity from Marvin, we believe replacing your windows is a decision that should only be made once. We developed the perfect window material in the industry so you can enjoy the strength, performance, and beauty your home deserves.


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