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Vinyl v. Fiberglass Windows: A comparison in cost, durability, and more

June 24th, 2021 | 8 min. read

Vinyl v. Fiberglass Windows: A comparison in cost, durability, and more

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A close-up shot of a white window frame.

Photo credit: Stilfehler. This image was not altered in any way. 

Choosing the right replacement window can be a tough decision. With the various options out there, how do you know which one is right for you?


You know wood windows exist, and you’ve heard of vinyl windows, but maybe you’ve just discovered fiberglass and want to learn more. 

So you’ve narrowed your top choices down to vinyl or fiberglass. How do they stand up against each other? Which window would be better for you?

Video: "Vinyl vs Fiberglass Windows (Cost and Durability)" Down Below

At Southwest Exteriors, we offer top-of-the-line vinyl and fiberglass windows. We are a trusted window replacement contractor for over 30 years in San Antonio and want you to be thoroughly educated on your window options. 

There are multiple options when it comes to window material type beyond vinyl and fiberglass. Though this article will compare the two, neither can be voted as better than the other. 

Choosing what window type is best for you all comes down to your goals and what you are looking to get out of your new windows.

This article will give a fair comparison of vinyl and fiberglass windows in categories like cost, durability, energy efficiency, and visual aesthetics.

After reading, you will have a clear understanding of the major differences between vinyl and fiberglass windows. Then, you will be able to make an informed decision on choosing either type of window for your replacement windows. 

Cost of Vinyl vs. Fiberglass Windows

One of the first things you probably want to know when comparing two different products is the difference in cost


Vinyl windows are one of the most affordable types of windows, however, this does not mean they are always cheaply made. 

While it’s true you can get a vinyl window that is poorly made for only $150 for a 3 ft. x 5 ft. window, it will not be the best quality as other vinyl windows.

The cost for a 3 ft. x 5 ft. vinyl window can range anywhere from $300-1,200 for a high-quality window. The average cost falls around $600 per window, including labor and installation. 

If you’re looking for the least expensive option for a replacement window, a high-quality vinyl window might be right for you.


Fiberglass windows are slightly more expensive than vinyl for a good reason. Because of the material they are made of, they are stronger and more durable, which we will get into in the next section.

The same goes for fiberglass in the idea that you can get a cheaply made window that is not going to last, or you can pay more for a high-quality, long-lasting window.

The average cost for a 3 ft. x 5 ft. fiberglass window is around $1,650, including labor and installation. However, you can get fiberglass windows as low as $100 if you install them for yourself.

The cost of any window depends on the quality. Factors like durability, energy efficiency, craftsmanship, and installation will affect the cost of that window. 

When considering how much you want to pay for your replacement windows, you must consider your goals for your project. If you are looking for the least expensive option, you cannot expect the highest quality product or installation.

If you are looking for a window that you want to last forever in your home, then it is worth it to pay a little more for a high-quality window. 

On the flip side, a less expensive, lower-quality window might be what you’re looking for if you just want to give your house a brand new feel before putting it on the market. 

Durability of Vinyl vs. Fiberglass Windows

Durability is one of the most important factors to consider when comparing different types of windows. If a window does not hold up to what you need it to, then you will find yourself spending more on repairs and possibly another replacement in the near future.


Vinyl windows are made of polyvinyl chloride or PVC. They are one of the most popular types of windows because of their price and durability.

They are considered highly durable and do not rot or rust like wood, metal, or composite windows. Vinyl windows are also highly scratch-resistant, so maintenance to keep them looking fresh is low. 

However, because of its material, vinyl windows are known to become misshapen under the weather. When constantly exposed to changing temperatures from hot to cold, the frames will expand and contract.

This causes the window to misshapen, crack, and ultimately lower its durability and energy efficiency. 

If vinyl windows are also exposed to an excessive amount of sunlight, this can cause their color to fade. 


Fiberglass windows are made from strands of fiberglass woven together and bathed in a resin until it is cured. This process makes fiberglass windows highly durable because of the way the fibers intertwine and bond with each other. 

Unlike vinyl windows, fiberglass does not expand and contract, so it is durable and long-lasting against changing temperatures. 

Because of this, fiberglass windows do not lose their resiliency like vinyl windows do, making them more durable. This makes it a viable option to stand against the harsh Texas climate.

Fiberglass also does not rot, rust, or corrode, and they require virtually no maintenance. 

Overall, fiberglass windows are more durable than vinyl windows because of their material make-up. 

Energy Efficiency of Vinyl vs. Fiberglass Windows

You want to know your windows can withstand various elements like sun, rain, and snow. Along with this, you want to know your windows are doing their job in insulating your home to keep outside water and air out. 

Energy efficiency is the second most important thing to consider when choosing what type of window you want. 


Vinyl is a thermal insulator, making it one of the most energy-efficient window types out there. This means that it will keep your home cool during the summer and warm during the winter.

However, their insulating performance depends on how well the window is sealed. With any window, once that seal is broken, your window is not insulating as it should.

If a vinyl window becomes misshapen or is not sealed properly, its insulating properties are out the window (no pun intended). 

This is why installing a window is just as important as the type of window you get. A poor installation means your window will not function and insulate your home the way that it should.


Because fiberglass windows do not bend or bow like vinyl, they are more resistant to possible seal failure. 

Compared to vinyl, they are similar in insulating properties. One major factor to consider that sets the two apart is the number of window panes.

Vinyl windows typically come double or triple-paned. Fiberglass windows, on the other hand, only come as double-paned. The more panes a window has, the better an insulator it will be. 

However, the number of panes you want your windows to be is up to you and whether or not the manufacturer can meet your wants. 

Another factor to consider when talking about energy efficiency is glass type. While this does not have anything to do with the frame, the glass is an important part of ensuring your window keeps excess sun heat out and keeps your house cool.

Visual aesthetic

Making sure your window is durable and energy-efficient is an important factor to consider when choosing a window. What you want your window to look like visually is another element to consider in your decision-making process.


Vinyl windows offer a simple and classic style. If you’re not looking for anything elaborate or extra, vinyl is for you.

Vinyl windows can come in almost any style you want like single-hung, double-hung, bow windows, bay windows, and custom styles. 

Overall, vinyl windows offer the most basic and minimalistic aesthetic. They have a sleek and smooth finish and can come in a variety of colors. 


Similar to vinyl, fiberglass windows also have a classic and sleek appearance. 

The biggest difference between the aesthetic of the two is that some fiberglass composite windows can be made to look like wood. This option is perfect for the homeowner who wants the look of wooden windows without all the maintenance.

Most fiberglass windows have a powder-coat finish, giving them a more matte appearance. 

When looking at vinyl and fiberglass windows together, they both show similar aesthetic value. There are always customizations that you have to consider when choosing a window and contractor that can do the job. 

Choosing the grid pattern, color, size, and finish are the biggest qualities to consider for the look and style of your windows. 

Vinyl v. Fiberglass: Which is right for you?

Now that you know the major differences between vinyl and fiberglass windows in cost, durability, energy efficiency, and aesthetics, you can better decide which is best for you and your project.

Vinyl and fiberglass windows are very similar in many ways, but their small differences can greatly impact your home in the long run. A fiberglass window is recommended for the average San Antonio home because of its increased durability and ability to withstand harsh climates.

High-quality vinyl windows are also a durable option, but they can be more susceptible to warping in extreme temperatures. If you want a less expensive option, then vinyl windows might be right for you.


Where to buy vinyl and fiberglass windows in San Antonio?

At Southwest Exteriors, we take pride in the thousands of satisfied clients we've helped. No matter what windows you're interested in, we have you covered with our wide selection of options, including VistaMark vinyl and Fiberglass Marvin windows. From the initial consultation to installation, our team is dedicated to exceeding your expectations and providing top-notch service at every step. With our expert guidance and high-quality products, you can feel confident that you're making a wise investment in your home. Let us show why so many homeowners choose Southwest Exteriors for all their window needs.


Southwest Exteriors offers both high-quality vinyl and fiberglass windows to fit whatever style you are looking for. If any issues occur with your windows once installed, the cost to fix that problem is covered under your warranty, and we will do everything we can to fix that issue.

Curious as to how much a full window replacement costs? Check out this article and video that details the top factors that influence the cost of a window replacement, like the window type, quality of window, and installation.