Shopping for new windows? Fiberglass has become a popular window frame material because it’s long lasting, more cost-efficient than wood and more durable than vinyl. It’s a low maintenance, weather-resistant material that is energy-efficient, and excellent at regulating temperatures and reducing energy costs — there are so many things to love about fiberglass!
Read on to learn everything you need to know about fiberglass windows, and why this innovative material is a smart choice for your home or business.
1. Fiberglass Windows are Highly Durable & Long Lasting
Fiberglass is highly resistant to bending, breaking, dents, chips, chalking, or fading. This means the window frame finish will retain its color for decades. It’s impact-resistant and stiffer than vinyl and wood, so it won’t warp. It’s also non-corrosive and non-conductive, so it won’t rust or transfer heat between indoors and outside.
Fiberglass window frames are engineered to last 50 years, which is much longer than alternatives like wood and vinyl. Fiberglass is stronger, stiffer, and less prone to damage, so it retains its structural integrity and appearance with almost no maintenance. While fiberglass window frames cost more, other types of windows need replacing every 20-30 years. When you do the math, fiberglass is the more cost-effective choice.
2. Fiberglass Windows are Weather Resistant
Because it’s lightweight yet highly resistant to warping, fiberglass is a superior material for both windows and doors. Fiberglass is a composite of glass fibers and resin that was originally invented to insulate commercial buildings. Today, fiberglass has been developed into a strong, weather-resistant building material that continues to gain in popularity.
Fiberglass resists water and moisture so it won’t ever warp, split or rot like wood can. Unlike vinyl, it expands and contracts at about the same rate as glass, so even in extreme temperatures it maintains its shape and seal. This is crucial to preventing air leaks that make your home drafty and difficult to heat and cool.
Marvin Elevate collection fiberglass windows on a home exterior
3. Fiberglass Is the Most Energy Efficient Window Material
Fiberglass has outstanding thermal performance and is the most energy-efficient window material on the market. Even in extreme temperatures, fiberglass frames maintain a strong seal that conserves energy. Because the material was originally designed as insulation, it’s no surprise that fiberglass windows have almost no temperature transfer. Unlike aluminum or vinyl windows, fiberglass does not carry extreme heat or cold through the frame.
4. Fiberglass Windows are Maintenance-Free
Quality fiberglass windows are virtually maintenance-free. Aluminum windows need to be oiled, and wood requires repainting and resealing. However, the only upkeep fiberglass requires is periodically cleaning the frames and replacing the weatherstripping about every ten years.
This durable, stable material does not warp, expand or contract from temperature changes, so it maintains its tight glazing seals for decades. This makes fiberglass an ideal replacement material for rotted wood, old vinyl, or aluminum windows.
5. Fiberglass Offers More Benefits Overall Than Any Other Material On the Market
Fiberglass Vs. Wood Windows
For centuries, window frames have been made from wood; this natural material looks beautiful and is easy to paint or stain. Wood windows can be made in a multitude of custom shapes and finishes. However, wood expands and contracts with temperature changes and can warp if it absorbs moisture; this is why it’s common to see old wooden doors that no longer fit the frame. Unfortunately, wood that warps or swells can break the seal around the glass, creating a drafty window, and increasing your energy costs. To protect them from moisture, wood windows need a high-quality paint or sealant.
While aesthetically appealing, wood windows are more expensive than fiberglass and need regular painting and sealing for maintenance. The Elevate Collection from Marvin Windows offers a solution to this problem, with wood window frames that are protected by fiberglass exterior cladding.
Marvin Elevate casement window with Ultrex® fiberglass exterior and wood interior
Fiberglass Vs. Vinyl Windows
If there’s one advantage to vinyl window frames, it’s their lower up-front cost. However, with a lifespan of about 20 years, they’re not as cost-effective as fiberglass windows because you must replace them twice as often. Typically made from PVC plastic, vinyl windows are low maintenance. But they are sensitive to temperature changes and can soften and melt in high temperatures, resulting in seal failure.
Fiberglass Vs. Aluminum Windows
The final option for window frames is aluminum, which is a strong, lightweight metal. Aluminum windows last around 30 years and require little upkeep. However, they are most appropriate for mild climates. Aluminum has a high level of heat transfer so it doesn’t protect interiors very well from extreme heat or cold. Fiberglass is far superior because of its excellent insulating properties.
Marvin Essential fiberglass windows in a living room
Are fiberglass windows worth the investment?
Absolutely! Fiberglass has become one of the most popular options for window replacement because it is highly durable, cost-effective, and attractive. It costs less than wood and more than vinyl, with none of the drawbacks of either.
Why We Love the Marvin Brand for Fiberglass Windows
As a premier manufacturer of high-performance fiberglass windows in America, Marvin has perfected the formula for fiberglass windows and doors. Ultrex® fiberglass by Marvin is a high-quality composite of fiberglass and polyester resin. Known as pultruded fiberglass, this composite material is thermoset, meaning it won’t soften or melt in high temperatures, no matter where you live. Thermoplastic frames made from vinyl do not have the same stability and often warp in extreme heat.
Marvin Elevate collection fiberglass windows in a kitchen
Marvin fiberglass windows are also known for having narrow sightlines and a sleek aesthetic that suits modern home designs. They are available in a range of colors with optional interior finishes in wood. You can use fiberglass windows anywhere in the house as they come in a variety of shapes, sizes, and styles.
Ultrex® Vs. Marvin High Density Fiberglass
Marvin’s first foray into fiberglass began over 20 years ago when they introduced Ultrex® fiberglass, a composite that is eight times stronger than vinyl and three times stronger than a vinyl/wood composite (Fibrex®). It comes with a fade-resistant acrylic coating that is three times thicker than the competition.
Marvin’s proprietary High-Density Fiberglass is available in their Modern line. Engineered for very large windows, this fiberglass composite is designed to be extra thin and durable. It meets the unique structural requirements of large window walls, and supports narrower window frame designs for more expansive views.
Fiberglass patio doors by Marvin Windows & Doors
Both of Marvin’s unique fiberglass composites have a 50-year warranty and meet the AAMA 624 finish requirements. This means they have excellent gloss retention and resist fading and chalking, even in dark colored finishes.
Marvin offers its fiberglass construction in casement and double hung windows, picture windows, awning windows, bay and bow windows, and patio doors. Marvin Ultrex® fiberglass exterior finishes are available in their Essential and Elevate collections; you’ll find their high-density fiberglass on both interiors and exteriors in their Modern line.
Fiberglass Windows in Marvin Windows Collections
Marvin Signature Modern Fiberglass
- Designed to provide clean sight-lines with minimally intrusive frames.
- Innovative high-density fiberglass material for outstanding thermal performance, and optional low-gloss aluminum interior finishes
- Available as a modular system of awning, casement and fixed glass windows, with a flat casing to create a clean, uncluttered look.
- Five exterior colors; choose different interior and exterior color finishes, or match them for a cohesive design.
Marvin Elevate Fiberglass
- Proprietary fiberglass exteriors offer lasting performance that resists chalking and fading. Wood interiors are bare pine that can be custom finished.
- Designed for both new construction or replacement window projects; includes most popular shapes, styles, and sizes.
- Combines the superior strength of fiberglass with the natural beauty of wood.
- Select from six exterior finishes and black, clear coat, or pre-finished white interiors.
Marvin Essential Fiberglass
- Ultrex fiberglass that is virtually maintenance-free.
- Designed for both new construction or replacement window projects; includes most popular shapes, styles, and sizes.
- Durable fiberglass resists sagging; streamlined options simplify the ordering process, with versatile styles for almost every project.
- Available in three colors including bronze, ebony, and stone white.
Shop For the Best Fiberglass Windows At Ring’s End
Are you building a home or considering replacement windows? You’ll love Marvin’s extensive selection of designer window options – and their uncompromising quality. Choose among four high-quality collections and a range of price points, each with an industry-leading warranty.
Our window experts make it easy! They’re ready to help you navigate through the choices, set up an installation plan, and deliver your doors safely and efficiently.
Ring’s End also offers direct window installation on both new construction homes and renovations. Our installers are fully licensed and insured, and trained in manufacturer’s recommended installation methods in compliance with the manufacturer’s warranty. Click here for more information on window installation or schedule a visit with one of our Marvin experts. Get started today!