Vinyl and Fiberglass Window Replacements

Vinyl vs. Fiberglass Windows

Windows are a fundamental part of every home. Not only do they provide protection from the elements and allow sunlight into your space, but they also enhance your home’s aesthetic and could potentially raise its curb value. However, not all windows are created equal. Certain windows won’t provide the same benefits for every home, and each type of window comes with its fair share of pros and cons that homeowners should be aware of before making any major renovations or purchases.

Thinking of Replacing Your Windows? You Have Choices

There are plenty of window materials out there, from vinyl to aluminum to wood. Perhaps the two most popular styles found on modern homes in the U.S. are vinyl and fiberglass. If you’re considering upgrading your windows soon, it’s fair to question which material will best fit your home. Some factors to consider are strength, durability, cost and energy efficiency, among others.


You may not think much about window appearance – the whole point is to look through them, after all – but fiberglass and vinyl windows have some aesthetic differentiators worth noting. Fiberglass windows can be painted, customized upon purchase and can closely mimic the appearance of wood windows. Vinyl windows, on the other hand, cannot be painted and tend to have a “plain” look.

Fiberglass windows also have more glass surface area than vinyl. This is because vinyl materials aren’t as strong, so more material is needed to construct the frame, resulting in less glass space. If more natural light and more versatile appearance options are important to you, consider fiberglass over vinyl.


Vinyl windows are more affordable because the material is less expensive and installation tends to be less labor intensive. Prices will always vary depending on the window size and installation job, but overall, you can expect to pay about 10 to 30 percent more for fiberglass windows than vinyl.

Part of the price difference is attributable to the fact that fiberglass windows must be professionally installed and cannot be purchased from a home improvement store. On the plus side, this should provide some peace of mind because you’ll be getting the best possible product as well as installation with an expert’s touch.


Home builders today commonly use vinyl windows because they’re more affordable, readily available, easier to install and nearly maintenance-free. Another plus is they’re often made of polyvinyl chloride (PVC) with ultraviolet light (UV) stabilizers, so they won’t fade in the sun or rust. Most vinyl windows should last up to 30 years on average.

Fiberglass windows are also very durable, with an estimated lifespan of about 50 years. Because the frame is reinforced with glass fibers rather than just plastic, fiberglass windows are more resistant to expansion and contraction in high or low temperatures, frame warp, and general distortion. Homeowners who choose to paint their fiberglass should know that they may have to re-paint it at some point if peeling occurs.

Energy Efficiency

Overall, both vinyl and fiberglass tend to be energy-efficient choices, especially when compared to outdated or damaged windows. However, the hollow frames and air gaps that can develop in vinyl windows make for less-than-ideal insulation. If contraction occurs in a vinyl window, gaps and seal leaks can develop and lead to window fogging and the buildup of moisture in between the panes. Fiberglass windows are better insulated and will not shrink or expand.

Resale Value

If you’re looking to add resale value to your home, you really can’t go wrong with either choice. A recent estimate pinned an ROI of 74 percent on vinyl windows.1 Less resale value data exists for fiberglass windows because they’re a relatively new product. However, many experts believe they will potentially have a more significant impact on resale value because of their durability, energy efficiency and versatile appearance.

And the Winner Is…

At Gravina’s Window Center of Littleton, we recommend our customers choose the Infinity from Marvin because it’s simply the best fiberglass window on the market. The Infinity’s Ultrex® fiberglass is tough, energy-efficient and completely customizable to fit your aesthetic needs. If you’re ready to make the upgrade to fiberglass windows in your Denver-area home, contact Gravina’s Window Center by filling out an online form to receive a FREE estimate today!



Who makes the best fiberglass replacement windows?


Built with Ultrex® fiberglass, Infinity windows and doors are the perfect choice for any remodeling or replacement project. They’re tough, beautiful and extremely durable.

window replacement denver

Denver Fiberglass windows from Gravina's Window Cente

marvin windows dealers

Denver Fiberglass windows from Gravina's Window Cente

Built with Ultrex® fiberglass, Infinity windows and doors are the perfect choices for any remodeling or replacement project. They’re tough, beautiful and extremely durable.

These are the facts:  Ultrex Fiberglass is eight times stronger than vinyl and three times stronger than composites. That’s as tough as steel. So when a house settles and time marches on, Infinity replacement windows stay true and resist sagging—proving that they’re truly the best fiberglass window on the market.

Ultrex fiberglass gives homeowners windows and doors that are...

• Low Maintenance – Ultrex performs beautifully for years to come, with a finish that requires virtually no maintenance.

• Energy Efficient – Ultrex’s minimal thermal conductivity serves as a built-in insulated barrier against the elements – reducing heating and cooling costs.

• ENERGY STAR® certified – The Energy Department estimates that by installing ENERGY STAR-rated products, the average U.S. household can reduce its annual energy bill by 15 percent.

• Environmentally Friendly – Ultrex takes less energy to create – about 80 percent less than aluminum and about 40 percent less than vinyl. Also, it’s made mostly of glass, which is made from sand and gravel – a plentiful resource.

• Beautifully Designed – Made by wood window experts at Marvin, Integrity features traditional profiles and details that are more attractive than the “flat” appearance of other materials. Ultrex ensures it will stay beautiful for years to come.



Fiberglass Replacement Windows Denver



We think it goes without saying that Infinity windows, made from Ultrex fiberglass, are the best fiberglass windows on the market.


Ultrex fiberglass marvin windows replacement


Contact your us today to schedule an in-home consultation and don’t forget to ask about Marvin's patented Ultrex fiberglass!  Call 303-794-0490

Is it time to start using fiberglass replacement windows in your home?

"High Fiber"

Michael Anschel is not a fan of vinyl windows, but he loves wood. “Wood requires very little additional energy to manipulate,” says the principal of Otogawa-Anschel Design-Build in Minneapolis. “It is stored carbon, it can be easily handled when its useful life has ended, and it is beautiful.”

But if Anschel had to compromise, he would go with fiberglass.

“I feel better about fiberglass,” Anschel says. “The expansion and contraction of the frame material and the glass are closer, so durability is increased. They are more stable overall, and failures seem less likely.”

Fiberglass windows have been around for a while, but in recent years the product has achieved a higher profile. Because of the many benefits, manufacturers say it’s the perfect material for windows.

“The superior characteristics of fiberglass that make our lives mobile, safer, and convenient are the same qualities that contribute to making a solid, long-lasting window,” says Dave Koester, wood and fiberglass products brand manager at Medford, Wis.–based Weather Shield Windows & Doors. “It’s energy efficient, durable, and doesn’t become brittle. It’s also resistant to water, scratches, dents, and corrosion.”

Strength is one of the most oft-reported benefits of fiberglass. Warroad, Minn.–based Marvin Windows and Doors says its Integrity brand of Ultrex fiberglass windows is as strong as steel and is eight times stronger than vinyl. “In fact, it’s so tough, we have to use diamond-edged blades just to cut it to size,” the company says.

infinity from marvin fiberglass

Fiberglass also is a good energy-efficiency option. The Energy Department says fiberglass windows have air cavities similar to vinyl and when “these cavities are filled with insulation, they offer superior thermal performance compared to wood or vinyl.”

So if fiberglass windows are so great, why aren’t they more popular? Cost might be the main reason.

“Because of its durability, fiberglass is the most expensive window material on the market,” says the Seattle-based window dealer Keystone Windows and Doors. In other words, manufacturers charge a premium for the material.

Sizes and features are also limited. John Kirchner, public relations manager for Marvin, confirms that there are limitations “due to the strength and durability of the fiberglass making it difficult to bend and shape.” Round tops or radius windows are not possible, he adds.

Still, if you can work around those constraints, fiberglass offers features and attributes that your home buyers will love. Moreover, it has “the benefit of being able to mimic the appearance of wood, which improves consumers’ acceptance of the product,” Anschel says.

Original article from 2012 at

fiberglass replacement windows

How Strong is Ultrex?

How Strong Is Ultrex Fiberglass?

That's a tough question to answer but it doesn't stop us from trying!  Infinity replacement windows and doors are built from Ultrex fiberglass, a tough, rigid material that delivers outstanding finish and performance. They'll never leave you and your construction, remodeling or replacement project hanging. You won't find a stronger window on the market. Not only is it 8x more rigid than vinyl, just one inch of Ultrex can hold up to 34,000 pounds!

Our Windows Are 8X Stronger Than Vinyl

Infinity from Marvin fiberglass windows are 800% stronger than vinyl and 300% stronger than composite windows. Don’t make the blunder of selecting vinyl windows that will eventually have to be replaced. Experience the beauty, coziness, and security of Infinity Windows for as long as you own your home. Do it right the first time and choose Infinity from Marvin – Built for Life!


Introducing EverWood from Marvin Windows

Natural Wood Interior
EverWood Interior

Windows with the look, the warmth, the color of real wood

Gravina's Window Center of Littleton is Proud to Offer EverWood

Wood windows have adorned homes for centuries, and they were built initially by craftsmen with an artisans touch.  Now
modern-day wood windows continue to convey that sense of hand craftsmanship and are often selected for their traditional detail and their ability to be stained. When you stain a real wood window that adds warmth, beauty, and charm to a home.  Upholding that charm and beauty long term is going to require periodic care and preservation.

No More Wood Maintenance

Introducing EverWood, Infinity's engineered interior wood grain finish that looks feels, paints and stains like wood, yet is virtually no maintenance. It's natural beauty compliments any interior woodwork in your home.  Get all the benefits of a wood window in an unrivaled, durable replacement window by Infinity from Marvin.