Fiberglass vs. Vinyl Windows—What’s the Difference?

Apr 20, 2021

Fiberglass vs. Vinyl Windows Are you living in a home that has aging or builder-grade windows? If so, replacing your windows is one of the best upgrades you can make. Inferior windows deliver subpar insulation and weather resistance, which means your windows could be racking up unnecessary energy and maintenance costs simply by not doing their job to the fullest extent.

However, if you’re like many homeowners, you may find the replacement window market to be a bewildering jungle of options from dozens of window manufacturers, all claiming to make the most beautiful, enduring, and energy-efficient windows a homeowner can buy. As you continue your research, you’ll undoubtedly learn that fiberglass and vinyl are better choices for window frames than wood or aluminum. But why? Because wood-frame windows are vulnerable to rot and termites, which means they’ll require more intensive upkeep than many 21st-century homeowners have time for. And aluminum can’t compete with newer window-frame materials when it comes to beauty or energy efficiency.

So, now that we’ve established that your new replacement windows should have either fiberglass or vinyl frames, what’s the difference between the two?

Brawny & Beautiful—Must Be a Fiberglass Window

Fiberglass window frames are among the most recent advancements in window construction. Their main claim to fame is their outstanding strength, which plays a big role in their energy efficiency, weather resistance, and eye-catching appearance. High-quality fiberglass windows are stronger than their wood or vinyl counterparts, and fiberglass is far less prone to shrinking and swelling during temperature changes. Both of these characteristics mean that fiberglass frames can be remarkably slender and still securely hold a large expanse of glass while keeping the window seal intact. As a result, a well-constructed fiberglass window will:

  • Sport a sleek and sophisticated appearance that will enhance any home’s curb appeal
  • Provide more expansive views of the great outdoors than most other types of windows can
  • Prevent air infiltration, which can undermine energy efficiency
  • Protect your home from water leaks and moisture intrusion, which can lead to mold growth and structural damage

The Virtues of Vinyl Windows

Vinyl has become one of the most popular frame materials for replacement windows, and its superiority over wood and aluminum is practically indisputable. High-quality vinyl window frames will look lovely for many years with no maintenance required apart from an occasional cleaning. Moreover, premium vinyl frames can be engineered to provide exceptional insulation against outside temperatures, and they’re also available with foam insulation for maximum thermal protection. When crafted with energy-efficient glass, vinyl windows are often the ideal choice for homeowners who want to reduce their carbon footprint and keep their heating and cooling costs in check.

Whether you gravitate toward fiberglass or vinyl for your home’s replacement windows, you’ll want to keep in mind that opting for high-quality materials, construction, and installation services will all be important if you want the best bang for your buck.

The experts at Johnson County Siding & Window Co. have been outfitting homes throughout the Kansas City metro area with beautiful, long-lasting replacement windows for more than 40 years. We’ve scoured the market for the best-performing windows to install for our customers, and we’ve chosen to offer windows from two of the industry’s most recognized names: Marvin®, a leader in fiberglass window construction, and ProVia®, an award-winning vinyl window manufacturer. We’ve also gone the extra mile to earn certification credentials from these esteemed manufacturers, which means you can rest assured that any windows you receive from us will be flawlessly installed according to the manufacturer’s specifications.

If you’re planning to replace the windows of your home in the Kansas City area and you’d like to explore the merits of fiberglass vs. vinyl windows even further, contact Johnson County Siding & Window Co. today. We’ll be happy to provide details about our beautiful replacement windows and tell you about the financing options available to qualified homeowners.


If you know you want to get your home exterior project done, but are feeling stress about paying for it all at once, we can help.

Our financing partner, GreenSky, has sensible payment plans that work for homeowners who prefer to pay in installments. You can also ask your JoCo Siding & Window Co. sales representative about the details!

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with the purchase of a ProVia Fiberglass Entry Door

* Free offer includes storm door model #397 only.

Our Customers LOVE The Results

Johnson County Siding & Window Co.
"The whole process was easy and the service was fantastic. When Lynn arrived to install the door he was on time and started right away. He got the old door torn out and the new one installed. He took the time to answer all the questions I had about the install and when done it looked amazing. When my wife got home she was so happy to see how good the new door looked compared to the old door. Every part of the experience working with Justin and his team has been wonderful.”

- Ash A.
Johnson County Siding & Window Co.
"Our home had the original, 1961, drafty windows. The sashes would not stay up and cleaning the upper windows was a long, hard process. After meeting with several companies, we choose Johnson County Siding & Windows. They have a great rating and have been in the business for many years. The windows are good quality, economical, and so easy to open and clean. The installers were very professional, kept the area clean, and preformed the job in the time frame we were given. I would highly recommend using Johnson County Siding & Windows.”

- Brenda M.
Johnson County Siding & Window Co.
"Johnson County Sliding and Windows installed new siding on our home and did an excellent job. We did a lot of research and interviewed several companies before moving forward. It was a huge project! We worked with Justin, who helped with the estimate and communicated with us before, during, and after the project was completed. He was friendly, easy to work with, and professional. He made sure we felt completely satisfied. We found him to be trustworthy and he always followed through with our requests whether they were big or small. The crew completing the work were friendly and hard working. I never felt uncomfortable or questioned the work they did. Everyone from the installers to the group delivering the supplies were kind and courteous. Just with any large project, we had some minor details that we requested be addressed (paint touch ups and reframing our garage differently). All of the requests were handled quickly and without any push back or difficulty. Our home went from a dilapidated, woodpecker damaged eyesore to the best looking house on the block! I couldn’t be happier and highly recommend Johnson County Siding and Windows!”

- Sara D

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Serving the Kansas City Metro Area, Including Olathe, Overland Park, and Leawood See a Full List of the Cities We Serve