2023 Fiberglass Windows Prices, Options, Pros & Cons

Typical Cost To Install 10 Windows Price Range: $3,150 - $6,570
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Fiberglass windows have become a more popular option for most contractors and homeowners who are looking for high-quality window frames for their work.

What makes fiberglass windows stand out is their expansion and contraction due to the outside temperature being so minimal it’s nearly non-existent. That’s good news for window seals and energy efficiency.

Fiberglass windows can range from $304 to $649, but that price can fluctuate depending on various factors like size, type, and whether it’s a ready-made window or a customized one.

One of the major disadvantages of fiberglass windows is that they are prone to moisture, resulting in mold growth, thus depreciating the value of your home.

However, fiberglass windows are highly flexible, soft to the touch, and easy to clean. You can always spend a few minutes of your time cleaning them to prevent the growth of moisture.

What Are Fiberglass Windows?

Fiberglass windows are a special type of window made from resin and fiber, making it a more robust window frame than wood with energy-efficient insulation.

The windows remain intact in all weather conditions. In addition, they are simple to install and give your home a fancy look. The high-quality fiberglass windows help elevate your home’s value and save you from regular window replacement costs.

What Are Fiberglass Replacement Windows Made of?

As the name suggests, fiberglass windows are made of fiberglass or a combination of glass fibers and resin.

The windows look like vinyl or wood but have a thinner frame. The windows have a modern appeal, making them stand out from other window types.

Average Total Cost of Fiberglass Windows

Window Style Average Total Cost (Ready-Made) Average Total Cost (Custom)
Transom $190-$332.50 $247-$665
Single Hung $190-$1,425 $247-$2,850
Double Hung $237.50-$1,900 $308.75-$3,800
Picture $266-$2,565 $346.75-$5,130
Arched $285-$1,045 $370.50-$2,090
Window Size    
Small $190-$950 $247-$1,900
Average $285-$1,710 $370.50-$3,420
Large $380-$3,040 $494-$6,080

Fiberglass window costs largely depend on whether you use prefabricated ones or order custom ones. The type of window can also factor into the cost.

The national average cost of installing a fiberglass window is $416, but homeowners can pay between $304 to $649 depending on their location, window type, size, etc.

Labor to install a window typically costs between $38 and $57 per hour, but depending on local rates, that’s subject to change.

To put it into better perspective, replacing 10 windows can cost as low as $3,040 or as high as $6,490, including materials and labor.

Cost of Custom vs Prefab Fiberglass Window

As mentioned before, the cost per fiberglass window depends on a couple of factors. First is the choice to use prefabricated or custom ones.

Prefab windows are ones you can buy ready-made from any window retailer. These types are great if a retailer carries the exact window size and type you need in stock and can cost $641 to $1,045 per window.

Custom windows are a little trickier to buy. This is the only option if you can’t find the right size or type at a retailer, typically the choice if you have an older or unique home.

It can get a little pricey. Homeowners can expect to pay $846 to $2,090 per window, but the cost can increase depending on the uniqueness of the specifications.

Additional Cost Factors to Install Fiberglass Replacement Windows

Anytime you think of purchasing fiberglass windows, always keep in mind that there are additional cost factors that you need to incorporate into your budget. These factors are:


When you have plans to replace your fiberglass windows, you may need to acquire a building permit, depending on the extent of the project.

The cost of the building permit varies depending on your location, but it can cost between $47.50 to $285.

Window Style

The style of the fiberglass window you want will determine how much you are likely to pay. Here are the average costs for popular window types:

Transom – $190 to $332.50 (ready-made), $247 to $665 (custom)
Single Hung – $190 to $1,425 (ready-made), $247 to $2,850 (custom)
Double Hung – $237.50 to $1,900 (ready-made), $308.75 to $3,800 (custom)
Picture – $266 to $2,565 (ready-made), $346.75 to $5,130 (custom)
Arched – $285 to $1,045 (ready-made), $370.50 to $2,090 (custom)

Keep in mind that these figures represent the material cost and do not include the installation.

Window Size

The window size is also used to dictate the cost of the window. Below are some averages for comparison:

Small (awning, transom, smaller than average sash) – $190 to $950 (read-made), $247 to $1,900 (custom)
Average (egress, sash, small picture) – $285 to $1,710 (ready-made), $370.50 to $3,420 (custom)
Large (bay, garden, large picture and arched) – $380 to $3,040 (ready-made), $494 to $6,080 (custom)

Again, these prices are just the average material costs. It doesn’t factor in the installation price.

Pane Type

Single-pane windows may be the traditional choice, but nowadays, homeowners have many more glass types to choose from – and they can drastically increase the price of the project.

The most budget-friendly glass type is the abovementioned single pane. It doesn’t have much in the way of insulation, but the average price range is $190 to $475.

For more insulation, you can opt for a double-pane glass ($237.50 to $760) or a triple-pane glass ($427.50 to $1,852.50). The gas-filled panes will cost quite a bit more at $380 to $1,805 for Argon and $617.50 to $2,375 for Krypton.

Specialty glass panes such as Low-E ($332.50 to $1,187.50) and spectral coating ($356.25 to $1,757.50) are also available in both ready-made and custom windows.

Pro Tip. Always check the labels on the fiberglass windows before buying. Most fiberglass windows may look similar, but they may have very different capabilities in terms of functionality.

The only way to note this difference is to read the labels attached to the windows.

Replacement vs. New Window in Existing Wall

Replacing an existing window generally costs less than installing one in an existing wall. Unlike a window installation to an existing wall, installers don’t have to create a hole to accommodate a new window with a replacement.

Expect to pay around $95 to $285 for the labor to install a replacement window (materials not included). The cost is $475 to $1,475 just for the work to add a window to a wall.

Where to Buy Fiberglass Windows

You can visit a physical store or shop from a reputable online supplier for fiberglass windows. You can buy from popular manufacturers such as Pella Impervia and Andersen Windows by visiting a local showroom or visiting a reseller. Check out the official website for more details.

Fiberglass Window Advantages and Disadvantages

Fiberglass windows have pros and cons and are not the perfect solution for everyone.


Highly Durable

Fiberglass windows are durable and can last more than 50 years without needing a replacement, provided they are properly maintained. The window frames are strong, and they do not wear out easily.

High Energy Efficiency

Fiberglass windows aren’t easily affected by the outside temperatures, and their expansion and contraction are nearly non-existent compared to other types.

They also don’t conduct cold or hot air. That means that the temperatures inside the home stay consistent.


If environmentally friendly home improvements are a priority, you’ll be glad to know that fiberglass helps keep your impact on the planet low.

Its insulating properties ensure that you won’t need as much gas or electricity to regulate temperatures in the home.

Low Maintenance

Fiberglass does not call for regular maintenance compared to windows made from wood. An occasional swipe from a damp cloth is all you need to keep your windows clean.


Relatively Expensive

Fiberglass windows are relatively expensive compared to other window types. You are likely to pay up to 30% more for a single fiberglass window than a vinyl window.

Fewer Options

When you opt for fiberglass windows, keep in mind that there are only a few options to choose from. It’s available in fewer colors and hardware compared to wood windows.

Not Easily Found

These window types are not as readily available as wood and vinyl windows. You may need to check on multiple suppliers before getting one that suits your needs.

Pro Tip: Fiberglass windows are prone to fading when exposed to UV rays for long periods. Once it starts fading, you can acquire a long-lasting coating to maintain its appearance.

Fiberglass Windows vs. Vinyl

Vinyl windows, such as Alside, are relatively thick compared to fiberglass.

They have visible join lines located on the corners. Fiberglass windows do not have join lines, giving more space to the glass panes. As a result, fiberglass utilizes more natural light at home due to the huge glass pane space available.

However, fiberglass windows are more expensive and difficult to find than vinyl ones. They cost 30% more than vinyl windows due to their strong and durable material, among other features.

Installing vinyl windows is simple due to their flexibility. Note that vinyl windows can expand and contract, which can result in the breakage of window panes. Fiberglass is rigid, ensuring that the window panes remain intact regardless of the change in weather.

Due to the rigid nature of fiberglass windows, they require a professional contractor to do the work. Conversely, vinyl windows are more flexible, making them easier to install as a DIY project.

Fiberglass Windows vs. Aluminum

Aluminum and fiberglass windows are designed to suit multiple architectural designs, and they are highly customizable. What makes them different is that fiberglass window frames are relatively strong compared to aluminum ones.

Even though aluminum windows are some of the best options available, they have low energy efficiency. Aluminum conducts heat at a faster rate making it a poor insulator. Fiberglass is an incredible insulator which makes it a highly energy-efficient option.

Even though aluminum windows are more expensive than vinyl ones, they are still cheaper than fiberglass windows.

Fiberglass vs. Wood Windows

Fiberglass windows are relatively strong, and they do not fade easily compared to windows made from wood. When wood windows are exposed to sunlight for a long time, they fade, requiring a replacement or painting to refresh them.

Since wood windows are made from natural materials, they are eco-friendly materials. The only problem is that they expand and contract based on weather changes. This constant fluctuation will eventually damage the window seals.

Fiberglass, on the other hand, barely expands and contracts so that the seals stay intact longer. This means consistently lower energy bills than wood windows.

Also, fiberglass windows are more durable when compared to wood windows. Wood windows are prone to insects and moisture, shortening their lifespan, whereas fiberglass windows won’t suffer these issues.

Lastly, wood windows are more expensive to install at $7,125 to $13,300 compared to fiberglass.

Fiberglass Windows vs. Composite

Fiberglass windows and composite windows are relatively similar due to the material they are made from. However, composite windows tend to differ since they have thicker frames. Also, they vary from one manufacturer to the other.

Fiberglass outshines composite in terms of energy efficiency, given that fiberglass windows do not allow the penetration of hot and cold air into the house.

Composite windows can be made from different materials, such as wood fibers and plastics. Thus, energy efficiency depends on the type of material used.

Composite windows are available in a wide range of styles, and you can choose based on your preference. On the other hand, fiberglass windows have limited options to choose from, although you can repaint them with your preferred coating.

Pro Tip: When living in an area that experiences humid summers and extended winter seasons, you may need to install a triple glass panel to enhance the durability of your fiberglass windows.

If you purchase black fiberglass windows, keep in mind that they absorb more heat which can result in the cracking of the glass.

Are Fiberglass Windows Safe?

Fiberglass windows are safe and add an attractive appearance to your home. However, you are at a high risk of inhaling the fibers during installation. This is why it’s recommended to hire a professional technician to do the job.

The fibers from fiberglass windows are hazardous since they can irritate your throat, eyes, and skin. The good news is that the risks are also resolved once the fiberglass window is installed.

Are Fiberglass Windows Fire Resistant?

Even though fiberglass windows have much to offer homeowners, they cannot be used for fire protection.

Although fiberglass is treated with fire retardants to survive a fire, they’re not ideal in areas prone to fire outbreaks.

Who Makes the Best Fiberglass Windows?

Different companies across the globe make fiberglass windows but try going for products generated by reputable brands to ensure consistent quality.

Evaluating some of the best companies available is important before deciding where to buy your fiberglass windows. Companies such as Pella, Marvin, and Andersen have an exceptional reputation for high-quality fiberglass windows.

How Long Do Fiberglass Windows Last?

Fiberglass windows can last up to 50 years before needing a replacement. However, the windows can only achieve this lifespan with proper care. You need to ensure that the windows are thoroughly cleaned to prevent dust from piling.

Also, it’s a good idea to cover window frames with a proper coating to minimize UV ray damage. When the fiberglass window is exposed to UV rays for a long time, the color fades and will likely start deteriorating over time.

Once the fiberglass window starts fading, it’s a sign of aging. However, you can always get a way to turn around the situation by coating it. Coating the fiberglass window improves its longevity and the value of your home.

Pro Tip. The window frame is a crucial component of a fiberglass window. Aside from keeping the glass in place, it also ensures that the window is energy efficient, keeping outside temperatures where they belong – outside.

What Colors Do Fiberglass Windows Come In?

Fiberglass windows come in different colors, such as brown, black, and white. There are also dual-color frames that you can choose to match the colors of your siding.

The dual-color frames are what they sound like, whereby you can have one color on the interior and do a different option on the outside.

When going for a dual-color window frame, you can opt for a black interior frame and a brown or white exterior, depending on the design of your home. Also, there are solid color frames with the same color on the interior and exterior.

Applying a solid color with a powder coat finish can complement your home.

In addition, other manufacturers produce fiberglass windows with metallic shades such as gold and silver. Remember that you can also give suggestions based on your needs to match your home’s aesthetics.

Do Fiberglass Windows Fade?

Yes. Fiberglass windows fade over time, especially when exposed to UV rays for a long time. Even though most manufacturers claim that their fiberglass windows do not fade, the weather in your local area will be the ultimate decider. For example, if you tend to experience long seasons of sunshine, the windows are likely to fade.

Also, applying a powder coating on the fiberglass window enables it to withstand all weather conditions, including fading.

Can Fiberglass Windows Be Painted?

Fiberglass windows can be painted, although new windows do not need the paint since the color is still intact. When you want to switch the color by painting, you need to refinish the frames and apply a coat of paint just as you do on wood.

Is Fiberglass a Good Material for Windows?

Fiberglass is a quality material for windows that offers excellent benefits like durability, low maintenance, and energy efficiency. It’s also an eco-friendly material that can help keep your heating and cooling bills low.

Moreover, the manufacturing process to make fiberglass windows prevents them from developing seal-related complications. As a result, they can serve you for over 50 years and more.

Make Fiberglass Windows a Part of Your Home

Fiberglass is a reputable window material that has transformed the creation of quality home windows.

This is an excellent option for anybody that wants durable windows that will serve them for at least half a century.

Although this window option can be pricier than others, the investment is worth it in the long run.

Typical Cost To Install 10 Windows Price Range: $3,150 - $6,570
See costs in your area

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