Choosing a Window Material: Vinyl or Fiberglass?

Home renovation is no small task. You probably already know that choosing the right materials to use in your remodels will make a world of difference down the line. What building materials are best suited for window frames? Fiberglass and vinyl are both readily available options and are comparable in a number of ways, but each material has its own pros and cons.

It’s important to take the big picture into consideration. Let’s take a closer look at some of the most important deciding factors, including cost, maintenance, insulation, and others.


Both vinyl and fiberglass are highly varied in appearance and can be tailored fairly readily to your specifications. Vinyl is pre-colored, which means nicks and scratches will be essentially invisible. However, be aware that if you choose vinyl for your replacement windows, you’ll be stuck with the color you pick. Vinyl can’t be easily repainted, and darker colors may fade over time due to sun and weather exposure.

Fiberglass, on the other hand, readily accepts paint – although it’s also available in a number of pre-selected colors and finishes. The material is highly resistant to dents and scratches. Additionally, because it’s a stronger material, fiberglass has the benefit of providing more glass space than vinyl. This is a significant benefit for homeowners who want to let more natural light into their homes. It’s a perfect framing material for windows with multiple panes or for large openings due to its structural stability.

Vinyl and fiberglass are both highly customizable, especially when you work with K & B Home Remodelers. We’ve partnered with some of the best names in the industry, including Beechworth Fiberglass and ProVia Vinyl. Choose from an extensive collection of vinyl styles and colors, or take a look at the many surprising possibilities fiberglass replacement windows will offer. You can even enjoy the aesthetic of wood frames with a customized solution that provides the durability of manufactured material.


Vinyl is a much more affordable material upfront than fiberglass, although the price can be comparable when you factor in size, frame style, double-paned or triple-paned glass, insulation, finish, and more. Expect to pay anywhere from 15 to 30 percent more for fiberglass at a base price.

Fiberglass does have a higher resale value than vinyl. Additionally, fiberglass windows are growing significantly in popularity – which means they may increase the value and overall appeal of your home in the long run.

Durability and Maintenance

Both vinyl and fiberglass are equally low maintenance, requiring little to no attention throughout their lifetimes. Neither material will rot when exposed to moisture, and both resist insects and other critters – unlike wood, which as an organic material is highly sensitive to water damage, termites, rot, and more. Additionally, neither material will rust or splinter.

However, fiberglass replacement windows definitely beat vinyl in terms of durability. According to one case study, fiberglass windows last 38 percent longer than vinyl. Made of spun glass fiber sourced from silica sand, it reacts to temperature changes essentially the same way that the glass panes do. As a result, fiberglass reduces internal stress to the window.

While vinyl won’t damage your glass panes, it won’t be as airtight as fiberglass, so you may have to replace your weather stripping more often. On the other hand, fiberglass will help prevent air leakage – meaning that any expanding or contracting due to temperature won’t affect the window’s performance.


Fiberglass and vinyl are equal in their insulation properties. On their own, the benefits are comparable, and both can be filled with insulation material in their hollow cavities. As such, both vinyl and fiberglass replacement windows will help slow the transmission of outside temperatures into the home – whether you’re heating or cooling your interior.

Other factors, such as the type of glass you choose, will also have an influence. High-efficiency glass will contribute significantly to the thermal performance of your windows whether you opt for vinyl or fiberglass.

Because vinyl expands and contracts more than fiberglass, it can require a little extra maintenance to ensure optimal thermal efficiency. While the window frames themselves are highly durable, you should make sure to check the surrounding caulking and insulation periodically to make sure you don’t have any leaks or drafts.

Environmental Impact

Vinyl is made from extruded polyvinyl chloride (PVC). Depending on the brand, it may also have metal structural elements within the framing. While vinyl is usually less expensive than other materials, PVC isn’t the most eco-friendly material around. In cases of building fire or waste burning, PVC can emit toxic dioxins, hydrogen chloride, and other carcinogenic substances.

The vinyl industry has significantly reduced the presence of problematic substances, but the nature of the material is such that the risk can’t be fully mitigated. Nevertheless, vinyl is a long-lasting material that can be recycled, making it a reasonably eco-friendly choice.

Fiberglass still tops vinyl in terms of longevity, however. Additionally, the manufacturing process is far less intensive, with fewer toxic byproducts and less energy usage overall. Because it lasts longer and is less prone to damage, there hasn’t been much need to recycle or repurpose the material thus far.

Recycling fiberglass is a challenge, but because it’s made from sand, a sustainable resource, it remains an environmentally friendly material. Notably, fiberglass can still be recycled, but it requires a specialized process to grind down the material and convert it into filler for other construction materials.

Work with K&B Home Remodelers

So what’s the verdict between vinyl and fiberglass replacement windows? Ultimately, it’s up to you. Your choice will depend on your needs as a homeowner. As evidenced by the many differences outlined above, vinyl is a more affordable choice, while fiberglass is a higher quality material with a higher resale value.

At K&B Homes, we specialize in both materials, so our experts can help you evaluate the best option for your home. Above all else, we stand for quality, which is why we’ve partnered with Beechworth Windows to provide the best fiberglass replacement windows available.

For more information or to request a free quote, contact us today.

About Mike Damora

Mike Damora is vice president of sales and marketing at K&B Home Remodelers, in Randolph, N.J. You can follow him on Twitter @madamoracatch him on Drift.