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Homeowner’s Guide to Fiberglass Windows

Fiberglass windows are a strong and durable option for your home. Read on to learn about the pros and cons of fiberglass windows.


When it comes to selecting the right material for your windows and patio doors, homeowners should consider their lifestyle, budget, desired aesthetics, energy efficiency and the strength and durability of window materials. We've rounded up important information about fiberglass windows in comparison to vinyl and wood windows to help you choose the right window material for your home and lifestyle.

How are Fiberglass Windows Made?

Fiberglass is naturally strong and durable. As a composite material, it is commonly made with randomly blown glass rovings and a heated resin to make a single, new thermoset material that is strong and durable. Because of these material properties, fiberglass is a trusted choice for tools, boats, bridges and windows and patio doors. After the thermoset material is created, it is then pulled through a die to make the pieces of a window frame, finished and painted.

But not all fiberglass is created equal. Pella's proprietary fiberglass material is the strongest material for windows and patio doors, engineered for lasting durability.61 As a leader in innovation since 1925, with over 17 years’ experience in fiberglass, we created our proprietary fiberglass material to give our customers more. Our exclusive formulation withstands extreme temperatures and is engineered to last a lifetime. Through a one-of-a-kind manufacturing process, our fiberglass is created with our strong structural mat and strategically placed rovings. These rovings are pulled through a machine (commonly known as pultrusion), injected with polymer resin and heated to create a thermoset material. This new thermoset material won’t break down when exposed to environmental temperature extremes. Our fiberglass is then finished with a long-lasting powder-coat finish, meeting AAMA 624, which is a highly-rated fiberglass coating.

Fiberglass Windows vs. Vinyl Windows

Fiberglass and vinyl windows are both good options for your home and each material can help you accomplish different goals you might have for your windows. Learn about the unique advantages each material has in order to choose the right windows for your home.

Fiberglass Window Material is Stronger Than Vinyl

When comparing fiberglass vs. vinyl windows, our proprietary fiberglass material has superior strength.61 On average, our fiberglass material is more than 11 times stronger than vinyl and will resist bending and breaking.61 And our fiberglass is 2 times more impact resistant than vinyl, a test that shows us how a material is able to withstand a sudden force that could cause breaking.61 Pella's fiberglass windows will resist bending, denting and breaking for long-lasting performance. This superior strength also means that you can have thinner sightlines, more glass and bigger sizes. For added strength, durability and reliable water performance, Pella Impervia fiberglass windows are secured with corner locks, metal fasteners and injected with sealant.

Fiberglass Offer More Design Options Than Vinyl

Fiberglass and vinyl windows are both beautiful options for your home. Fiberglass windows are available in five modern colors, including Black, which Pella vinyl windows are available in up to three interior colors. With both materials, you can choose from solid- or dual-color frames for added design interest. Your fiberglass windows will never need painting or refinishing. The tough-as-nails powder-coat finish resists chalking and fading, even in dark colors. Depending on the finish, hardware options and grille patterns, your fiberglass windows can provide a modern or traditional look for your home. Fiberglass casement and awning windows are available with the patent-pending Easy-Slide Operator hardware, an innovative way to open and close your windows. Simply slide the hardware operator to open and close the window.

Fiberglass Windows are More Than Energy-Efficient

Fiberglass and vinyl windows both offer energy-efficient options to keep your home comfortable. They offer energy-efficient options that will meet or exceed ENERGY STAR® guidelines in all 50 states.1 And you can increase your energy-efficiency further with optional foam insulation and triple-pane glass. But fiberglass windows help keep your home even more comfortable. Available on casement, awning and direct set windows and sliding patio doors, optional triple-pane glass improves noise reduction and increases energy efficiency. And they’re tested to the extremes, from -40°F to 160°F, so our fiberglass windows will keep your home comfortable no matter the weather outside.

Fiberglass Windows Typically Cost More Than Vinyl

Fiberglass windows typically cost more than vinyl because they offer more design and energy-efficient options and are built from an extremely strong and durable material for a lifetime of everyday use. But with sleek designs and innovative features, it’s easy to see why fiberglass windows demand a higher price. Compare fiberglass and vinyl windows to decide which is best for your home.

Fiberglass Windows vs. Wood Windows

Fiberglass and wood windows are both beautiful, high-performing options for your home. With unique pros and cons of wood windows and fiberglass windows, learn which option is right for your home.

Fiberglass Windows are Stronger Than Wood

Pella's proprietary fiberglass material shows superior strength over wood.61 Our fiberglass material is, on average, 11 times stronger than wood.61 On average, it is five times stronger than wood in a bend test, showing us how resistant they are to bending and 8 times more impact-resistant, a test that shows us how a material is able to withstand a sudden force that could cause breaking.61 It resists bending, denting and breaking.

Modern and Traditional Aesthetics for Your Home

Both fiberglass and wood windows will provide a beautiful look for your home. Fiberglass windows feature slim, sleek profiles, which is a great way to give your home a modern aesthetic. Choose a black fiberglass window and one of our sleek hardware designs to further your modern design. Our fiberglass windows are available with your choice of five grille patterns that will help create a modern or traditional aesthetic, or choose a custom grille pattern for a unique look. And with minimal maintenance, fiberglass windows will remain a durable option for your home, no matter your style. Wood windows offer more design flexibility with both traditional, ornate profiles and contemporary style. They're available in a variety of paints and stains to create the ideal look for your home.

Energy-Efficient Fiberglass and Wood Windows

Fiberglass windows are incredible energy efficient. Our proprietary fiberglass material is one of the best insulating materials and is ENERGY STAR® certified. Optional foam insulation and triple-pane glass helps increase energy efficiency further. Wood is a natural insulator, and wood windows are also available with optional foam insulation and triple-pane glass. Either option will help keep your home comfortable and protected from the elements.

Fiberglass Windows Typically Cost Less Than Wood

When comparing the price of fiberglass and wood windows, fiberglass windows are typically less expensive. They are a great choice for homes that want high-performing, long-lasting windows that are usually less expensive than wood. Wood windows are available with wood-clad or wood exteriors. Wood exteriors can require regular maintenance from time to time. Fiberglass windows are maintenance-free with a durable powder-coat finish that never needs to be painted or refinished.

Ready to find the best windows for your home? Here are five things to keep in mind when shopping for the right window.

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