Fiberglass windows are prized for their ability to withstand the elements without extensive maintenance.
Compared to vinyl frame windows, fiberglass windows last longer, are more weather resistant and energy efficient, and offer a more upscale look and feel.
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How Much Do Fiberglass Windows Cost?
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Typically homeowners spend $750-1,000 to install a single fiberglass window, depending on the window brand, style and local labor rates. Installing 10 fiberglass windows costs $7,500 – 10,000.
The average cost of a double hung window with a fiberglass frame is $750 – 850, including installation.
The price ranges, on average, between $850 and $1,100 installed. For a high-end fiberglass window, you can pay as much as $3,000, and a simple fixed window can be installed for as little as $400.
You can use our Windows Cost Calculator to get a quick an accurate estimate for the cost of replacing windows in your home.
Fiberglass Window Price Break Down
$3,520 - $6,895
In terms of prices for the window itself, they range from being as low-cost as vinyl windows, to being more expensive than real wood windows.
Fiberglass window prices vary depending on the type of window you purchase, such as single-hung, bay, or sliding, window size, as well as the window brand you choose.
|Budget Cost Range||$195 – $480|
|Average Cost Range||$750 – $1,100|
|High-End Cost Range||$1,300 – $3,000|
Installation Cost Of Fiberglass Windows
Fiberglass windows cost a lot to install as they are one of the more difficult window materials to work with.
For this reason, its best not attempt to install a fiberglass window without professional help unless you have experience in window installation.
On average, professionally installing a double-hung fiberglass window costs between $175 and $300 per window.
Cost of installation varies widely depending on the type of window you are installing–a bay window will easily cost $500 – 750 to install, while a single-hung window can be as low as $150 – 170.
In addition, your total window installation cost will depend on whether the pros need to repair any damage to the existing frames as well as also paint them. This can increase your total cost by as much as 15-20%
Some contractors will charge per hour, whereas others will charge you a flat rate. Professional window installers typically generally charge between $50 and $75 per hour.
Expect laborers to work for a minimum of two hours, but often much longer, to install each window. Contractors will often have a minimum cost of around $150.
Factors That Influence The Cost Of Fiberglass Replacement Windows
You may be wondering what are the primary determinants of cost for a fiberglass window. It is important to consider what impacts pricing so you can properly budget for your project and take into consideration all of your needs and circumstances.
Here is a quick run down of the main factors that will ultimately impact your total window replacement cost:
Window Brand: The brand you choose will be a primary factor in determining costs. Some brands are more high-end and expensive, such as Alpen, whereas others like Pella are more affordable.
Window type: Windows come in many styles, and some are more expensive to manufacture and install than others. Bay and bow windows are the most pricey type, whereas fixed or single hung windows are the most affordable.
Customization: Most brands offer customers an array of features which can be customized. For starters, a window you buy off the rack from Home Depot or Lowe’s will be cheaper than a window ordered from a company where you choose features such as the frame color, hardware, or glass.
You can also purchase fully custom windows designed to fit your specific needs. These are the most expensive type of windows.
Window Glass There are many types of window glass, which all impact cost. The most affordable option is a low-E coating on double paned glass, filled with either argon gas or air. More expensive options include triple paned glass, hurricane-grade glass, and other glass designed for specific climates.
Frame Color: Brands often offer an array of colors to choose from, which can affect the price of your window. Darker colored frames tend to be more costly than light-colored frames.
Additionally, if you choose a different color for the interior and exterior, that will increase costs.
Fiberglass Replacement Windows Prices By Style
The style of window you choose will be one of the primary factors determining the cost. Fiberglass windows are offered in all of the most popular window designs, such as double hung, awning, bay, and even custom designs.
The table below includes the average cost of a fiberglass window, depending on the style you choose (not including installation). The price will also vary by company and contractor.
|Window Type||Average Cost|
|Fixed Window||$250 – $575|
|Single Hung Window||$300 -$850|
|Sliding Window||$325 – $900|
|Double Hung Window||$450 – $1,500|
|Awning Window||$500 – $1,200|
|Casement Window||$550 – $1,500|
|Picture Window||$600 – $1,700|
|Bay Window||$775 – $2,500|
|Custom Window||$1,200 – $3,000 +|
$3,520 - $6,895
Fiberglass Window Prices By Brand
Many companies offer fiberglass windows, each at different price points. Alpen and Marvin fiberglass windows are the most expensive, whereas Pella fiberglass windows are the most affordable.
|Window Brand||Average Cost|
|Pella||$350 – $750|
|Marvin||$900 – $1,500|
|Alpen||$1,200 – 1,900|
|Milgard||$300 – $1,750|
|Andersen||$195 – $1,850|
|Kolbe||$800 – 1,000|
Marvin Fiberglass Windows
Marvin offers two lines of fiberglass windows: the Essential series and the Elevate series. Both are high quality, reliable window choices that will serve you well for years to come.
Marvin Essential Windows (previously known as Marvin Integrity)
Marvin’s Essential Series windows are made from durable fiberglass in both the window exterior and interior. This provides maximum strength, energy efficiency, and ease of maintenance.
The Essential line offers windows in a range of styles: casement, awning, double hung, single hung, glider, picture, round top, and specialty and customized shapes.
Essential windows are styled for a streamlined, smooth aesthetic without bulky interference in your view.
The average cost of an Essential Series window is between $900 and $1,050.
The Marvin Elevate series is made from fiberglass exteriors and wood interiors. This design combines the durability of fiberglass with the beauty of wood.
The Elevate series offers a compromise between the advantages and disadvantages of both materials, allowing you to have the best of both worlds.
With the fiberglass exterior, the window frames are protected against harsh elements, whereas the wood interior allows for a timeless interior appearance.
The Marvin Elevate series is offered in casement, casement narrow frame, awning, awning narrow frame, double hung, double hung insert, single hung, glider, picture, bow, bay, round top, and specialty and customized shapes.
A Marvin Elevate window is slightly more pricey than the Essential series, costing on average between $1,150 and $1,200.
$3,520 - $6,895
Pella Fiberglass Windows
Pella offers an affordable fiberglass window line called the Impervia Series. The Impervia is popular for its high performance at an affordable price point.
An Impervia window costs on average $480, including installation, although the cost will vary by window type.
Pella Impervia is offered in six window styles: double hung, single hung, casement, picture, sliding, and awning. Pella Impervia windows come in brown, white, and tan.
Windows in the Pella Impervia series range in cost from $350 to $750
Alpen Fiberglass Windows
Alpen windows offers fiberglass windows in the Zenith Series, which comes in five different versions that are all durable, low maintenance, and energy efficient.
Alpen is a relatively small window brand that is not known at all in many areas, and as a result it also has a relatively small distribution network compared to other much bigger brands.
Alpen fiberglass windows are considered to be top of the line when it comes to energy efficiency, and preform significantly better compared to top fiberglass window brands such as Marvin and Milgard. So if this is something very important for your home, its worth investigating further.
On the down side, Alpen fiberglass windows are very expensive, and cost about 40% more than Marvin windows. A single Alpen fiberglass window costs on average $1,250 – 1,900.
Alpen Zenith Series ZR-10
The R-10 line is a high-performance window line with a certified .10 U-factor for fixed windows and a .14 U-factor for operable windows.
The fiberglass frames are well-insulated, and the triple-chamber layers of glass provide additional insulation. The glass has 99.5% UV protection.
Alpen Zenith Series ZR-9
The Alpen Zenith ZR-9 line is offered in four styles: sliding, awning, picture, and casement. The series has a R-9.1 insulation rating, slightly less than the ZR-10 series.
Alpen Zenith Series ZR-7
The Alpen Zenith Series ZR-7 has insulation of R-7.1, which is higher than Energy Star standard, a key measure of energy efficiency.
The ZR-7 line is offered in a range of styles to suit your home’s needs: picture, casement, awning, single hung, double hung, sliding, and specialty shapes.
Alpen Zenith Series ZR-6
With a thermal performance rating of R-6.7, the Alpen Zenith ZR-6 line has somewhat lower insulation than its counterparts. However, the series has other benefits that add to the performance of the windows.
The window is built with triple glass panes and glazing that, in the center of the glass, has a higher insulation rating of R-8.
Additionally, the window is offered with glazing options to increase thermal protection and energy efficiency.
The ZR-6 line comes in several styles: picture, casement, awning, single hung, double hung, and sliding.
Alpen Zenith Series ZR-5 Contractor Series
The Alpen Zenith ZR-5 line is designed specifically for contractor use in the building of multi-family homes and complexes. They are the most affordable option offered at Alpen, offering durability and ease of installation and use for a competitive price.
The line has an insulation rating of up to R-5.9. The window is offered in a range of styles to meet the building project’s needs: casement, sliding, picture, awning, single-hung, double hung, and specialty shapes.
Milgard Fiberglass Windows
Milgard offers one fiberglass window line, called the Ultra Series. On average, a Milgard fiberglass window costs between $300 and $1,750, making it one of the mid-range priced fiberglass window options.
Milgard fiberglass windows are considered upscale and high quality.
The Ultra series is offered in four exterior color options: Black Bean, Bark, Harmony (a tan shade), and White. The line comes in a range of window styles, including single hung, horizontal slider, casement, awning, bow, bay, picture, and radius.
The Ultra series comes with Milgard’s impressive limited lifetime warranty.
Andersen Fiberglass Windows
Andersen has three different fiberglass window lines, which are called Fibrex, at different price points, that range from $195 – 1,850 for a single window.
Did you know? Fibrex is actually NOT 100% fiberglass material. Its a composite that is made up of 60% PVC vinyl and 40% recycled pine.
As such, Fibrex windows are more durable than wood windows, but they are actually less weather resistant than a 100% fiberglass or vinyl window.
So if you are looking for the extra perks and features that pure fiberglass windows offer, Fibrex windows may not be the right choice.
On the other hand, if you are looking for windows that really replicate the look of natural wood (neither fiberglass not vinyl can do that), but are more durable than wood, then Fibrex is an ideal choice.
The most budget friendly is the Andersen 100 Series Fibrex windows which range in price from $195 – 395.
100 Series windows are designed to look like wood and are marketed as being twice as strong as vinyl windows. They are available as single-hung, casement, awning and sliding window styles.
Renewal by Andersen
Next on the price scale is the Renewal by Andersen upscale Fibrex windows. They cost $985-1,985 and are considered some of the most costly fiberglass windows available.
Renewal fiberglass windows are available as double-hung, casement, awning, sliding windows, picture bay/bow and specialty custom windows.
Renewal windows come in 8 interior and 12 exterior colors, which can be mixed and matched, as well as 3 standard glass options.
Andersen Architectural Series ( A Series)
The A series Fibrex windows are most expensive and Andersen markets them as their best preforming windows.
The A-Series is offered in four window styles: Double-hung, standard awning, standard casement, picture, and specialty windows.
It comes in 13 interior and 11 exterior colors, as well as 4 standard and 8 specialty glass options.
In terms of price, an Andersen A-Series window cost between $1,000 and $1,750 making them one of the most expensive fiberglass windows on the market.
Kolbe Fiberglass Windows
Kolbe offers one line of fiberglass windows called the Forgent Series. Their fiberglass line is made from a unique, patented material called Glastra, which is a composite of fiberglass and a UV-stable polymer.
Glastra is made from recycled and repurposed material, making it an excellent choice for the environmentally conscious.
Forgent windows are offered in Glastra exteriors and interiors, or Glastra exterior and pine wood interiors. The pine wood interior is offered in a range of pre-finishes, including a selection of stains, black paint, white paint, a double clear coat, or latex primer.
On average, a Kolbe Forgent window will cost you $800, but the price varies.
What Are Fiberglass Windows?
Fiberglass is a man-made material known for its durability, and is used to make skis, canoes, and other strong items, in addition to windows.
Fiberglass is made from polyester resins that are pulled through a heated dye. Then, strands of glass or glass are infused with the resins, making a shapeable material.
Fiberglass is well-suited for use in windows because of its durability and strength. For one, fiberglass experiences very little expansion or contraction with temperature changes.
Because fiberglass is largely made from glass, the expansion and contraction it experiences is very similar to what the glass panes experience, which helps eliminate drafts and leaks.
Pros & Cons Of Fiberglass Replacement Windows
Fiberglass windows have many positive aspects, making them a popular window material choice, but fiberglass does have some drawbacks as well.
● Energy efficiency: Fiberglass windows are naturally insulating, helping prevent unpleasant temperatures from entering your home. This reduces your spending on temperature control such as AC or heating, while simultaneously reducing your harmful emissions into the environment.
● Low maintenance: Unlike wood windows, fiberglass requires very little maintenance to retain its quality appearance.
● Weather resistant: Fiberglass windows will be affected by moisture, which prevents all sorts of ailments that plague wood windows such as warping, cracking, or rotting.
● Limited thermal expansion and contraction: Fiberglass does not expand significantly as the temperature changes, preventing damage and leaks.
● Colors and styles: Fiberglass windows are available in a wide range of color and style selections to fit your aesthetic needs.
● Price: Fiberglass windows are generally more costly than vinyl windows. However, they are typically cheaper than wood or wood clad windows.
● Color limitations: While many companies do offer an array of fiberglass window colors, some fiberglass windows cannot be painted, which may limit your ability to match your new windows with the other colors in your home.
● Fading: Some darker colored fiberglass may experience fading over time from UV rays. This would be particularly problematic if you purchased a fiberglass window that cannot be painted.
$3,520 - $6,895
Fiberglass vs. Vinyl Windows
Homeowners often find themselves choosing between vinyl and fiberglass windows, as both material types have many similarities. There are, however, some key differences which can help you make the right decision on your new window.
While fiberglass is made from resin-infused glass, vinyl is made from PVC. Both are strong materials, but fiberglass is more robust and durable than vinyl.
Fiberglass windows can be up to eight times as strong as vinyl windows, and have an expected lifespan over twenty years longer than vinyl windows, lasting up to fifty years.
While fiberglass naturally resists expansion and contraction from temperature changes, vinyl does not have the same qualities, making it more susceptible to damage and warping.
Fiberglass is up to 15% better at insulating than vinyl, which keeps heating and cooling costs down. While vinyl is less naturally well-insulated, additional insulation can be easily added, but at an extra cost.
In addition to keeping energy costs down, the insulating nature of fiberglass also makes it better at blocking out unwanted noises than a vinyl window.
Additionally, fiberglass is a better window choice environmentally speaking. That is because the insulation of fiberglass windows, as well as its resistance to expansion and contraction reduce the emissions spent on temperature control.
Compare Fiberglass Windows vs Wood vs Vinyl vs Aluminum Windows
You may be deciding between fiberglass and other materials when choosing a new window for your home.
While fiberglass windows have many advantages, it is important to fully consider all window material options and compare the features of all of them.
Considering most factors, fiberglass outshines its competitors in most features.
|Wood Clad Interior||Available||Available||Unavailable||Available|
Fiberglass Window Maintenance
Fiberglass windows are a very low maintenance window material choice. The main element of maintenance is a semi-regular cleaning.
Unlike other window materials such as wood or even vinyl, fiberglass will not fade, warp, crack, or chip. Maintaining your fiberglass windows is easy and affordable.
To clean fiberglass, do not use a power washer, as it may damage the window. Instead, use a mild detergent mixed with warm water, applied with a rag or soft bristle brush.
Are Fiberglass Windows Worth It?
Fiberglass is one of the more costly window materials, but for good reason. Across the board, fiberglass window frames outshine other window materials in almost every category.
According to Remodeling Magazine, your estimate return on investment (ROI) when installing new fiberglass windows can be as high as 70-74%.
In colder climate, where energy loss is a big concern and windows play a key role in keeping the house insulated, installing new, energy efficient windows can bring as much as 85% return on investment.
This is one of the highest returns compared to other top remodeling projects.
Keep in mind that ultimately your return on investment will depend on the total value of your property, as well as the window brand you install. Prospective homeowners appreciate recognizable brand names and are willing to pay more for them.
overall, fiberglass windows is an excellent, reliable choice if you are seeking new windows that will last with little upkeep and keep your home insulated, safe, and comfortable.
$3,520 - $6,895