Difference Between Fiberglass and Vinyl Windows (2024)

Vinyl and fiberglass are both durable, energy-efficient, and low-maintenance, making them two very popular choices for window frame materials. However, they have significantly different price points. Fiberglass windows are more expensive and difficult to find than vinyl, leaving homeowners wondering whether they’re worth the extra money and effort. We’ll break down the differences between these two types of windows to help you make the right choice for your home.

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Fiberglass Windows: Overview, Pros, and Cons

Fiberglass combines strands of actual glass with heated and stretched polyester resins. The resulting lightweight and highly durable material is used in a range of applications, from surfboards to helicopter blades. Fiberglass window frames, which became popular about two decades ago, are usually designed to resemble wood windows and can even be painted like wood. The benefits and drawbacks of fiberglass windows in comparison to vinyl windows are outlined below.

Pros

• More durable and resilient
• Have a slightly higher resale value
• More eco-friendly

Cons

• Substantially more expensive
• Available from fewer companies

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Vinyl Windows: Overview, Pros, and Cons

Vinyl is short for polyvinyl chloride, or PVC. This versatile plastic is easy and inexpensive to produce, and when applied to a metal frame structure and insulated, it creates some of the most cost-effective replacement windows on the market. Quality vinyl window frames are available in a wide variety of size and color options and are the most popular choice for American homes.

Pros

• Less expensive
• Usually available in more sizes and styles
• More do-it-yourself-friendly (DIY-friendly) to install

Pros

• Not as durable as fiberglass
• Less eco-friendly than fiberglass

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Compare Fiberglass vs. Vinyl Windows

Now that we’ve covered the basics on fiberglass and vinyl windows, we’ll compare the two to help you choose which window type is right for your home and budget.

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Costs

The cost of new windows depends substantially on the frame material. A standard-size vinyl window typically costs between $100 and $900, whereas a similar fiberglass window typically costs between $500 and $1,500. Other factors, such as glass treatment, can come into play, so a single-pane fiberglass window may sometimes be less expensive than a double- or triple-pane vinyl window. Typically, vinyl windows will cost less than fiberglass. 

*Costs in this article are sourced from contractor estimates from Angi.

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Life Span and Durability

Fiberglass is more durable and long-lasting than vinyl. In extreme temperatures, the glass fibers are able to expand and contract alongside the glass panes in a way that vinyl can’t. This means fiberglass windows are less likely to experience seal failure, where the window panes and the frame pull apart. Failed seals lead to condensation and air leaks. Additionally, vinyl doesn’t keep its resiliency as well over time and may eventually warp or sag. Thus, while fiberglass windows may last 50 years, vinyl windows typically last 30 years maximum. 

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Energy Efficiency

Although both window materials are more energy-efficient than alternatives, such as aluminum, fiberglass offers better insulation, preventing heat from transferring through the window frame and into your home. Stronger fiberglass window seals also mean fewer air leaks, so your HVAC system won’t work as hard keeping your home at a comfortable temperature. This leads to energy bill savings, making fiberglass windows the better choice for homeowners in extreme climates.

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Maintenance

Maintenance is one area where these two window options are essentially equal. Both are extremely easy to clean with water and mild soap, and neither requires frequent sealing and repainting. While you can paint vinyl windows, you must sand them first and they don’t hold paint as well as fiberglass. For lower maintenance, choose vinyl windows in your desired color.

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Appearance

While these windows are difficult to distinguish from a distance, there are noticeable differences. Because they’re stronger, fiberglass windows don’t require as thick a frame. Thus, for a same-size vinyl and fiberglass window, the fiberglass window’s glass pane will be larger and allow in slightly more natural light. Fiberglass can also be textured to look like wood. Both types of windows are available in a variety of colors and styles.

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Installation: DIY vs. Professional

Window installation is a moderately difficult home improvement job, so some homeowners will opt for professional installation, particularly for above-ground windows. However, for DIY projects, vinyl windows are easier to install than fiberglass windows. Vinyl is more flexible and forgiving and can be purchased at home improvement stores. On the other hand, fiberglass windows must often be ordered from the manufacturer, and attempting a DIY install could void their warranty. 

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Additional Considerations

We’ve listed the most common consideration factors above, but there are other important differences between vinyl and fiberglass replacement windows.

Safety/Environmental Risks

Fiberglass may pose a slight safety risk during installation if the installer inhales glass fibers, but since they’re typically installed by a professional, the risk to homeowners is low. Once the windows are installed, there is no health risk from fiberglass.

Overall, fiberglass is more eco-friendly than vinyl, since it can be made from recycled glass. Vinyl is difficult to recycle, and it releases carcinogenic chemicals into the air during the manufacturing process. There may also be some slight off-gassing after installation, though the safety risk is very minimal at that point. (Off-gassing is the release of excess gasses from a material into the air.)

Resale Value

Since fiberglass windows are more durable and often considered more attractive, they maintain their resale value slightly better than vinyl windows. However, the difference isn’t large, particularly if the vinyl windows have energy-efficient features, such as double panes or extra insulation.

Window Brands

Nearly all top-rated window brands sell vinyl windows, but only some sell fiberglass windows. Pella, Marvin, and Milgard are three manufacturers that offer high-quality fiberglass windows.

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Our Conclusion

In comparing vinyl and fiberglass windows, the best windows for your home depends on your budget and needs. Based on our research, vinyl windows have the advantage when it comes to affordability, availability, and DIY-friendliness. On the other hand, fiberglass windows are more durable, energy-efficient, and eco-friendly. If you’re in the market for top-quality replacement windows and can’t make up your mind, consider an in-home consultation with a window expert. 

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FAQ About Fiberglass vs. Vinyl Windows

What is the difference between vinyl and fiberglass windows?

Vinyl and fiberglass are different materials that manufacturers use to make windows. Vinyl windows are easier to find and come with lower purchase and installation costs. In contrast, fiberglass windows are more durable and energy-efficient.

What are the disadvantages of fiberglass windows?

Here are the disadvantages of fiberglass windows:

• Fiberglass is more expensive than most other window frame materials.
• Fiberglass windows aren’t available from as many manufacturers.
• Fiberglass windows aren’t DIY-friendly.

What are the disadvantages of vinyl windows?

Here are the disadvantages of vinyl window frames:

• Vinyl is prone to warping, sagging, or cracking over time.
• Vinyl must be sanded before it can be painted.
• Vinyl is not recyclable or eco-friendly.

How much more are fiberglass windows than vinyl?

Vinyl windows typically cost $100–$900, whereas fiberglass windows typically cost $500–$1,500.

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