Fiberglass vs. Vinyl Windows: Which Is Right for Your Home?

Generally, windows come in five materials: aluminum, vinyl, wood, fiberglass, and composite blends. Each material varies in cost, energy efficiency, durability, appearance, and other factors that are likely on your list when comparing options.

Fiberglass and vinyl are two popular materials that provide great performance. Fiberglass is typically more expensive, but it has better longevity and energy efficiency. Vinyl windows are more affordable and widely available. Below, we go over each material’s advantages, which is better for your goals, and how to find a quality version of each.

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Our Take: Are Fiberglass or Vinyl Windows Better?

We’ll let you know upfront that fiberglass is the more expensive choice, but it offers more bang for your buck. It’s more energy-efficient, durable, and long-lasting than vinyl. Whether or not it’s worth investing in, though, depends on a few factors, such as your climate and how long you plan to live in your home.

If you decide to go with fiberglass, we recommend Marvin and Pella. If you decide vinyl is the better choice, we suggest looking into our reviews of Castle, Window World, or Champion.

Pros and Cons

Fiberglass performs better across the board, but if its price tag is out of reach for you, don’t worry. Today’s best window companies make plenty of high-quality vinyl options that still lower your energy bills and last for many years. Truthfully, the differences in the factors below aren’t astronomical. However, it may be worth investing in the edge fiberglass provides if your local climate calls for a more heavy-duty window.

Fiberglass

Vinyl

Fiberglass vs. Vinyl at a Glance

The table below highlights the main differences between fiberglass and vinyl window frames.

What’s the Price Difference—and Why?

As the superior performer, fiberglass is typically the more expensive window material. Vinyl is generally a more affordable window material, second only to aluminum. The price tag on your new windows comes down to the brand, special features (such as impact resistance, tinted glass, or noise blocking), window style, and size. The most basic fiberglass window from one brand could be comparable in cost to the most expensive vinyl option from another.

Because of those factors, price isn’t always straightforward. In early 2025, we surveyed 1,000 homeowners who had recently purchased replacement windows and learned that fiberglass windows cost an average of $651 per window, while vinyl windows cost an average of $558. That may not seem like much if you’re just buying one or two windows, but if you’re upgrading your entire house, it can be a difference of several hundred or thousands of dollars.

Based on our survey data, vinyl windows cost roughly $5,580 per 10 windows installed. Fiberglass windows cost $6,510 per 10 windows installed.

Our team also sourced cost data from Fixr to give you a glimpse of how much vinyl and fiberglass windows cost, which we highlighted in the table below. Note that installation costs are per hour.

Installation Costs

Installation costs can vary dramatically depending on numerous factors, such as project size, installation complexity, and installer experience. According to Fixr, installation costs $250 per vinyl window and about $300 per fiberglass window on average.

Long-Term Value and ROI

The long-term value of fiberglass or vinyl windows is a major reason to consider purchasing them. You don’t just increase your home’s curb appeal—you can also save money on your energy bills. The most important factor for energy efficiency is insulation, which reputable window brands add to both fiberglass and vinyl windows.

According to Energy.gov, fiberglass and vinyl have better energy efficiency than other frame types, such as metal frames. Due to their increased insulation, new windows can help keep unwanted heat or cold drafts out, which reduces the workload of your HVAC system.

According to our survey, the majority of homeowners saved between $25 and $60 (an average of $42.50) per month on energy bills after installing replacement windows. Homeowner Devin R. from Clarksville, Tennessee, reported that his new windows saved him an average of 20% in energy costs. He noted that his savings equaled roughly $450 annually.

Here’s how much you could save over 10 years if you replaced four fiberglass windows (the most common number in our survey):

• Four replacement windows = $2,604
• Average energy savings per month = $42.50 (average energy savings amount reported) x 120 months = $5,100 over 10 years
• After covering the installation cost, you’d save an average of up to $2,496 over 10 years.

Here’s how much you could save if you replaced four vinyl windows (the most common number in our survey):

• Four replacement windows = $2,232
• Average energy savings per month = $42.50 (average energy savings amount reported) x 120 months = $5,100 over 10 years
• After covering the installation cost, you could save up to $2,868 over 10 years.

Note: The average savings figures are for demonstration purposes only. Your actual savings may vary.

Do They Look Different?

Just because vinyl windows are cheaper doesn’t mean they look cheap. Most people aren’t going to spot the difference in vinyl and fiberglass’s appearance at a glance. However, some differences may make fiberglass more appealing to some homeowners.

For starters, you can paint fiberglass. That means you can get it in more colors, whereas vinyl typically comes in five to 10 standard neutral tones. Note that painting your fiberglass windows will require repainting at some point, since paint can deteriorate over time.

Fiberglass is also easier to texturize. This is beneficial if you want to mimic the look of wood without dealing with the upkeep of wood windows.

Lastly, vinyl frames are often bulkier than fiberglass. Vinyl is a more flexible material, which means you have to build a thicker frame to uphold its structural integrity. This isn’t a major difference compared to fiberglass, but it results in a little less natural light and outdoor view.

Which Performs Better in Real Life?

While fiberglass frames slightly outperform vinyl in regions with extremely hot or cold temperatures, both are suitable, energy-efficient choices regardless of where you live. Instead of focusing on your frame material for energy efficiency, you’ll want to make the right choice for the glass inside the frame.

If you live in a cold-weather region, you’ll want a window with a high solar heat gain coefficient (SHGC), which measures the solar radiation transmitted through a window. Windows with a low SHGC are better at collecting and retaining solar heat in the winter.

For example, if you live in a warm-weather climate, like Savannah, Georgia, you’ll want a window with an SHGC of 0.50 or above. On the flip side, homeowners in Portland, Maine, want an SHGC of 0.23 or below.

This number, along with the U-Factor, can be found on the sticker of the National Fenestration Rating Council (NFRC) certified windows.

What’s Inside the Glass: Panel Differences Between Fiberglass and Vinyl Windows

When comparing fiberglass and vinyl windows, the type of glass and spacer technology inside play a critical role in energy efficiency, comfort, and overall performance. For example, fiberglass windows often feature triple-pane glass that provides superior insulation and noise reduction, ideal for extreme climates. Gas fills and low-emissivity (low-e) coatings can enhance their performance further. Vinyl windows, typically equipped with double-pane glass, offer adequate insulation for moderate conditions but may not perform as well in very hot or cold climates.

Fiberglass windows often use advanced spacers, improving thermal performance, while vinyl models might include basic spacers that aren’t as effective at reducing heat transfer. If energy efficiency is a priority, upgrading vinyl windows to triple-pane glass could be an option, but be aware that the cost may compare to that of fiberglass.

Durability and Lifespan

A window’s lifespan is how many years its features will generally hold up and do the job manufacturers design them for, such as any glass coatings or insulation components. How long it can last varies based on the window’s construction and craftsmanship, but the window’s warranty is a good indicator.

Most window warranties cover the frame material and last 20 years or more. Some actually cover the material for as long as you own the home the window was installed in, meaning the manufacturer expects it to stand the test of time.

Fiberglass is known for having a longer lifespan than vinyl. Its structure is stronger and more weather-resistant. It’s not as prone to warping and cracking as vinyl is, so your window’s seal is less likely to break. In U.S. climates, it can last up to 50 years or longer before it starts underperforming. 

Vinyl has a lifespan of 20–30 years, but typically gives way to the elements before fiberglass frames. It’s vulnerable to extreme temperatures, causing its appearance and energy features to break down more quickly.

Energy Efficiency

Fiberglass was created specifically for insulation. It’s made from glass fibers embedded in resin. It doesn’t expand and contract much when exposed to fluctuating temperatures outside, so it’s better at stabilizing your home’s temperature inside.

Fiberglass windows typically have U-factor ratings as low as 0.20, meaning better insulation and reduced heat loss. Manufacturers often pair this window material with triple-pane glass for maximum efficiency. The thermal stability of fiberglass makes it a better choice for climates with extreme temperatures, such as northern areas or desert areas that have hot days but cool nights.

Brands build vinyl frames from polyvinyl chloride (PVC), which is a synthetic plastic polymer. It’s durable but more vulnerable to heat and cold, since its U-factor is generally higher than fiberglass variants. This tendency to expand and contract with temperature swings makes it harder for it to stabilize your home’s temperature compared to fiberglass. For those in more moderate climates, vinyl should still provide the energy performance you need. Vinyl windows typically come with double-pane glass since it’s suitable for most climates.

We recommend looking for a window’s Energy Star label, regardless of which window material you’re considering. This label tells you it has a certification from Energy Star, plus the climate it’s best suited for.

What Does Upkeep Actually Look Like?

Both fiberglass and vinyl are low-maintenance window materials—far more low-maintenance than wood windows, for example. If they accumulate any buildup, you can easily scrub it away with some warm, soapy water and a brush. 

Be aware, however, that painted fiberglass may fade and eventually need to be repainted every 10–15 years. Also, because vinyl tends to expand and contract under long-term sun exposure, you may need to replace the caulking every few years.

Installation Considerations

Due to their differences in structure and rigidity, you must make different choices when installing a vinyl window versus a fiberglass window. We provide a detailed breakdown of each below.

Vinyl: More DIY-Friendly (With Limits)

Since vinyl is more flexible, it’s easier to install. It’s also more forgiving of slightly off measurements. Because of this, an experienced DIYer can likely install vinyl windows and avoid paying an extra $100–$200 per window for professional installation. That’s why it’s common to see premade vinyl windows in home improvement stores, whereas fiberglass windows come straight from the manufacturer. However, if you don’t have the required tools, you’ll need to weigh whether investing in the necessary equipment to do the job is still cheaper than hiring a pro.

Fiberglass: Professional Installation Recommended

Fiberglass is a rigid material, so everything must be exact. It’s also heavier and requires more reinforcement. For these reasons, you must hire a licensed installer or use the manufacturer’s in-house installation team.

Regardless of which material you choose, always check your window warranty to see if there are any terms stating that using an unlicensed installer will void your warranty coverage.

What Do Most Homeowners Choose—and Why?

According to the Inter­national Association of Certified Home Inspectors, vinyl windows make up more than 50% of residential window sales. Interestingly, we found that our survey respondents also preferred vinyl windows as their frame of choice. Over 32% reported buying vinyl windows, while nearly 23% chose fiberglass. We believe that the affordability, customization, and wide availability of vinyl windows contribute to their popularity with homeowners.

Our team also interviewed actual homeowners to hear about their preferences. Joy A. from San Diego said that she bought vinyl windows but would choose fiberglass if she could do it over again, mostly due to the better durability fiberglass offers.

Expert Verdict: Which One Is Better?

Choosing between fiberglass and vinyl windows largely depends on your design preferences and budget, since each window type offers similar energy efficiency. Our team interviewed several experts to hear their thoughts on which frame material is best.

Kriss Swint, director of marketing communications and design lead at Westlake Royal Building Products, had this to say about fiberglass and vinyl windows:

• Fiberglass windows are known for their superior durability, energy performance and curb appeal. However, modern innovations in vinyl are beginning to close the gap, offering solid performance, low maintenance, and energy efficiency at a more affordable price point. Vinyl windows can also be installed by an experienced DIYer, offering more cost savings, as opposed to fiberglass, which requires a professional to install. And with recent design-forward launches, vinyl windows now deliver on aesthetics, too, aligning with modern design trends without compromising performance.

We also spoke with Nicole Willits, the Strategic Product Initiatives and Sustainability Manager at Pella Corporation. Here are her thoughts:

• Choosing the right window material is a big decision for homeowners, and it depends on several factors, including energy efficiency, maintenance, durability, aesthetics, and budget.
• Fiberglass windows are ready to handle virtually anything life throws at them. They are very durable and best for homes in extreme weather conditions, such as the triple-digit heat in the desert southwest or below-zero temperatures in the northern parts of the country. [Fiberglass windows] are tested to extreme heat and cold, damaging UV rays, and conditions of seacoast environments.
• When you want low-maintenance, affordability, and energy efficiency, vinyl is the right choice. Pella’s unique vinyl formula is performance-tested for excellent weathering, durability, and color retention.
• When selecting windows, homeowners should reflect on what window qualities are most important to them. Don’t choose just based on cost. Instead, consider your long-term goals.

Explore Other Window Types

Looking beyond fiberglass and vinyl? Consider these other popular window frame options:

• Wood windows: These windows offer timeless aesthetics and great insulation but higher maintenance and upfront costs.
• Aluminum windows: Aluminum windows are sleek, durable, and lightweight but less energy-efficient.
• Composite windows: These windows have a blend of materials offering solid performance and flexibility at a competitive price.
• Clad wood windows: These windows have a wood interior with weather-resistant vinyl or metal exterior for the best of both worlds.

FAQs About Fiberglass and Vinyl Windows