The Pros and Cons of Fiberglass Replacement Windows

Margaret Wack
Written by Margaret Wack
Updated October 1, 2021
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Fiberglass windows are durable, energy-efficient, and come in a wide variety of styles

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Installing new windows is an excellent way to increase your home’s value, lower your energy costs, and make your home more beautiful. A relative newcomer to the window replacement industry, fiberglass windows are sturdy and versatile. Whether fiberglass windows are right for you depends on your home, your budget, and your personal preferences.

Pros of Fiberglass Replacement Windows

If you’re buying new windows, fiberglass is a great material choice for several reasons, including energy efficiency and durability.

Energy Efficient

Fiberglass doesn’t expand or contract and doesn’t conduct heat or cold. In other words, it’s a natural insulator. For comparison, they’re three times more energy-efficient than vinyl windows.


Fiberglass windows are durable, which means they’re sturdy, weather-resistant, and will last longer without becoming damaged.


Fiberglass windows come in a variety of colors and styles, and some manufacturers give you the option of having real wood placed over the top of the fiberglass on the interior side of the windows for that warm wood look and feel. You can also paint the windows with little prep work.


Fiberglass is made out of glass, which means it’s recyclable. If being green is important to you, fiberglass replacement windows are a good option.

Cons of Fiberglass Windows

While fiberglass windows have many benefits, they’re not the best choice for everyone.

Limited Options

Fiberglass windows are still relatively new, so there aren’t many brands available. This means that you’ll have less brand choice when it comes to your windows than if you choose windows made of other materials, like wood.

More Expensive

Fiberglass windows are more expensive than vinyl, so if you’re not going to be in your home for more than a few more years, the cost likely won’t be worth it.

Longer Lead Time

There’s typically a longer lead time when ordering this type of window. If you need your windows right away, this might not be the best material choice.


While fiberglass is still an attractive option, it may not be as desirable as wood windows for some homeowners.

Are Fiberglass Windows Right for You?

In the end, choosing the best replacement windows comes down to how you feel about the look, style, functionality, and cost. Fiberglass windows are a great option for many homeowners, but you should make sure that they meet your needs. You should get in touch with a window company near you to discuss your options.

FAQs About Fiberglass Windows

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Should I get fiberglass or vinyl windows?

Both fiberglass and vinyl windows are popular options. Fiberglass windows tend to be more durable, while vinyl windows are less expensive.

How much does it cost to repair windows?

Window repair costs range from $160 to $550. Costs can vary widely depending on what exactly is wrong with your window. For example, it costs around $245 to repair a thermal seal but only $70 to fix a cracked pane. If you need to repair a window, you should contact a window repair company near you for a personalized quote.

What other windows should I consider?

Fiberglass windows are a great replacement window option, but they’re not the only option. You may also want to consider other types of windows for your home. Vinyl windows are one of the least expensive options available. Wood windows provide great insulation and a classic look but require more maintenance over time.

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