Vinyl vs Fiberglass Windows

Windows are an integral part of your home and they provide beauty, energy efficiency, and protection. When buying or replacing a window, it’s important to get a material that offers you all three benefits. If you have narrowed down the list and are debating between vinyl vs fiberglass windows, this article will highlight a few tips to help you make the right decision.

Vinyl vs Fiberglass Windows

Over the years, window technology has advanced and now homeowners have better options. There are many factors to consider when looking for new windows, so it’s important as a homeowner to know as much as possible before deciding.

Fiberglass Windows

Fiberglass is produced when polyester resins are activated by a catalyst then pulled, or protruded through a heated dye. Glass strands are then saturated using these resins, and the resulting product is known as a lineal. Lineals are machinable and they can be molded into any shape. For a long time, we have used fiberglass to create lightweight and ultra-strong materials for canoes, surfboards, and skis.

Fiberglass achieved popularity in the early 2000s, and fiberglass-composite windows were developed to overcome certain limitations of vinyl windows.

Vinyl Windows

Vinyl windows are produced using extruded polyvinyl chloride (PVC) as the main material. They may incorporate metal in their internal structure to strengthen the frames.

These windows appeared in the scene in the early 70s when small window fabricators started offering vinyl-framed windows to create custom sizes that big window manufacturers could not produce. However, they became popular in the 1990s, and since then, large manufacturing companies offer full lines of vinyl-framed windows.

Comparison of Features

types of vinyl and fiberglass windows

Here’s an outline of the major distinctions between vinyl vs fiberglass windows to help you understand how each would work in your home.


Any window is mostly made up of glass. However, there are a few distinctions between vinyl and fiberglass window frames. From far, they both look relatively similar. But, vinyl windows have a conspicuous joint at the corners while fiberglass windows don’t. Fiberglass frames closely mimic the look of wood windows, but vinyl windows are more plain.

Fiberglass windows offer more options for color and style because we can paint them, but this means that these windows can fade and peel. The color in vinyl windows is manufactured in so they don’t peel or fade.


Whether you choose fiberglass or vinyl windows, both require little maintenance, a fact that is very appealing to homeowners. You can easily wash off and scrub any dirt, mildew, mold, or moss using a sponge and warm water.

However, both need some care over time. Fiberglass windows can peel or fade and need repainting to maintain their beauty. Vinyl windows can contract or warp, which can lead to a poor air seal that requires to be filled with caulk occasionally to prevent air from seeping inside.

But the material that requires less maintenance is vinyl. You won’t have to worry about repainting your windows as long as you give it a good cleaning every once in a while.

Costs Between Fiberglass vs Vinyl Windows

Cost is an important factor when considering replacing or buying windows. Sometimes, the cost alone can be the determinant factor for someone to choose one product over another. Usually, fiberglass windows end up being more costly than vinyl windows. Fiberglass is one of the most expensive window materials available.

When you consider the maintenance that the fiberglass windows will require, the cost will exceed that of vinyl windows. Vinyl windows are a more cost-effective choice since they are less expensive upfront and also in the long run.

Installation Factors

Vinyl is a highly flexible material that can contract and expand easily. Vinyl frames can also be produced to within 1/8 of an inch of the window size, and given their flexibility, they can be installed more efficiently and faster than a fiberglass window. Fiberglass is rigid and doesn’t contract or expand much. This means it’s more difficult to fit into your window opening and it will take more precision and skill to install.

It is always recommended to use a professional to install both types of windows. However, some types of vinyl windows can be a DIY project, but you shouldn’t install fiberglass yourself unless you’re a professional.

Aside from the difficulty and length of time required to install them, fiberglass windows often take longer to arrive. Since the material is relatively new, few manufacturers make them, and even fewer contractors have them in stock, which results in longer lead time.

Durability and Strength

Fiberglass is up to 8 times stronger than vinyl, and it can last significantly longer. Fiberglass windows can last up to 50 years or more, while high-quality vinyl windows can last up to 30 years.

Fiberglass is superior in strength because of its makeup. Fiberglass and vinyl frames are both made of plastic. However, fiberglass frames are fortified with glass fibers, which add even more tensile strength to the products, and this means that these windows can have thin frames with more glass on them.

Unlike vinyl frames that enlarge and contract when the temperature changes, fiberglass frames don’t soften in the sun. Vinyl melts at temperatures above 165 degrees, warping and distorting the frame, which can be a big problem on very hot days. Even on hot days, fiberglass maintains its integrity.

Energy Efficiency: Vinyl vs Fiberglass Windows

The glass fibers incorporated into a fiberglass window prevent the material from contracting or expanding, and thus it does not conduct heat or cold. This makes it a better insulator than vinyl.  Since the same fiberglass that’s used in insulating attics is already present in the frame, the frame becomes more energy efficient. Fiberglass is up to 15 percent more efficient in insulation than vinyl.

Both vinyl and fiberglass windows are good products and can be a better choice than wood in choosing new or replacement windows for your project.

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