Fiberglass windows vs. Vinyl windows


Whether replacements for existing windows or part of new construction, your home’s “eyes” to the outside world involve quite a few decisions to find the right set. Chief among them is the material for the frame and sash of your windows.

Currently, two of the most popular manmade materials for windows are vinyl and fiberglass. Vinyl is actually a truncation for polyvinyl chloride (PVC), a type of plastic. Fiberglass has a base of glass that’s melted under very high heat and then pulled into extremely fine fibers, which are woven together. If intended for solid construction, such as window frames, fiberglass is impregnated with various resins so it can be molded into shape.

Both fiberglass and vinyl are strong, durable, easy-care, and water-resistant materials that hold up to the elements far better than wood. Although it’s still considered the gold standard for window frames and sashes—thanks, mostly, to its lovely, traditional appearance—wood requires considerable maintenance to keep its good looks and prevent wear and tear.

Fiberglass gives a wider range of decorative options

While both materials look similar from a distance, and both can be quite attractive, fiberglass offers more variety in terms of window appearance. Fiberglass frames tend to be slightly thinner than vinyl, leaving more glass exposed—desirable when you want to let as much natural light into a room as possible. And while both materials come in a wide range of colors, fiberglass is paintable and vinyl is not. Finally, fiberglass can be textured to look like real wood, whereas vinyl is generally smooth.

Fiberglass is the most durable

Both vinyl and fiberglass tend to outlast wood, as they don’t rot or decay from moisture or insect damage, but fiberglass is the hardiest choice. A high-quality vinyl window will last around 30 years, while its fiberglass counterpart can still be gracing your home more than 50 years after installation. Fiberglass is stronger than vinyl and resists warping and cracking even under prolonged weather extremes. Vinyl expands and contracts with fluctuating temperatures, meaning that in the most severe climates, the seal between the window frame and glass pane can break, greatly reducing the insulating abilities of the window.

Fiberglass is more energy efficient

Although both materials are fairly good insulators and adequately control temperature loss or gain through the window, fiberglass does a better job. In fact, fiberglass was created in the 1920s specifically for use as insulation and it’s still commonly used for that purpose today. As a rough rule of thumb, fiberglass windows are as much as 15 percent more energy efficient than vinyl. And thanks to its glass base, fiberglass is very effective at insulating against sound, too—an important consideration if you live near a highway or other noisy area.

Fiberglass is more eco-friendly

Because fiberglass is more energy efficient than vinyl, it reduces energy consumption. And although not easy to recycle, most fiberglass is made from recycled glass, which means less glass in landfills and less need for new glass production. Plus, the manufacture of fiberglass doesn’t release harmful chemicals into the environment, nor will fiberglass windows off-gas or release potentially harmful byproducts should there be a fire in your home. By contrast, vinyl is not easily recyclable, produces harmful chemicals during production, and releases harmful fumes if melted in a fire.

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"Custom Exteriors provided a great product and good service in replacing 2 sliding glass doors and 2 other windows in my townhouse.  One was a custom window that required extra work in refitting the plantation shutters to the new window.  Although there were some bumps along the way, Jeff and his foreman Ryan excelled at follow up.  I would recommend Custom Exteriors."

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