How Much Does It Cost to Install a Fiberglass Window?

Average range: $600 - $1,000
Average Cost
(Single-hung window with frame painting, installed)

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Reviewed by Sophia Fennessy. Written by

Fiberglass windows are manufactured using fibers and resin. These materials do not expand and contract with temperature fluctuations, so they are an all-around great window type for all seasons. Fiberglass windows can be an excellent choice because they provide many benefits over other windows and can be purchased at a reasonable cost. This window type is becoming popular due to increasing thermal performance and lowering energy bills.

A professional is recommended to install fiberglass windows, and the installation costs vary, depending on the window’s type and size. The national average cost range is $600 and $1,000 for fiberglass window installation, with most homeowners paying $750 for a single-hung window plus frame painting. A simple fixed window can be installed for $300, but an installed custom bay window with insulation can cost up to $3,000.

Fiberglass Window Prices

Fiberglass window installation costs
National average cost$750
Average range$600 - $1,000

Fiberglass Window Installation Cost by Project Range

Fixed window, installed
Average Cost
Single-hung window with frame painting, installed
Custom bay window with installation, installed

Fiberglass Window Cost by Type

There are many fiberglass windows to consider, and the type you choose can have a big impact on your project’s final costs. Some windows are basic in design and cannot be opened, such as fixed windows. Other types are more elaborate and can open in different ways, resulting in higher average costs. The table below shows common window types, complete with estimated material costs.

Fiberglass Window Cost by Type

Fiberglass Window Cost  by Type

Window TypeAverage Costs (Material Only)
Fixed$200 - $550
Single-Hung$280 - $875
Sliding$300 - $900
Double-Hung$450 - $1,600
Awning$500 - $1,275
Casement$535 - $1,575
Picture$550 - $1,700
Bay$750 - $2,500

Fixed Fiberglass Window

A fixed window remains in place. It cannot open, so it is not designed for ventilation. It only allows natural light in. It is the most affordable and simplest option, with average costs ranging from $200 to $550 per window.

Single-Hung Fiberglass Window

Single-hung fiberglass windows are a type of sash window with two separate panels or sashes - one upper and one lower. In single-hung windows, the upper sash is fixed in place, and only the lower sash is operational, moving up and down to open and close the window. The average costs for these windows range from $280 to $875 each.

Fiberglass Sliding Windows

A fiberglass slider window is opened by pulling the sash side to side or up and down. They usually remain within the window frame when opened. These are good for wide openings to provide an unobstructed view. Good locations for installation are in rooms where you want maximum ventilation, such as bathrooms, basements, and even kitchens. The average cost of a fiberglass sliding window is $300 to $900.

Double-Hung Fiberglass Window

Double-hung fiberglass windows are another kind of sash window like single-hung windows, except they allow both the sashes to move up and down. This gives you more freedom to open and close the window, and some of them even allow the sashes to swing or tilt inwards. These windows are very popular in modern homes, and average costs range from $450 to $1,600.

Fiberglass Awning Window

Fiberglass awning windows are hinged on top and open outward. They are designed to maximize light and air inside. The best location to install these windows is in a bedroom or other area where light, air, and privacy are important. Awning windows are also often installed near other windows or above patio doors to create additional light in an entrance. The average cost for a fiberglass awning window is $500 to $1,275.

Fiberglass Casement Window

Fiberglass casement windows are compression-sealing windows that open 90 degrees for good ventilation, easy cleaning, airflow, and are watertight when closed. They are one of the most popular window styles around the world. Fiberglass casement windows are good for areas with a view. They are often installed in bedrooms, dining rooms, and spare rooms. Their average cost is $535 to $1,575.

Picture Fiberglass Window

A picture window is like a fixed window because it remains in place and cannot be opened or closed. Unlike other fixed windows, picture windows are typically large to offer a picture of the outside and let in as much light as possible. They are often found in living rooms, and their large size makes them quite expensive, with average costs ranging from $550 to $1,600.

Bay Fiberglass Window

Bay windows are among the most expensive types and aesthetically impressive. They consist of a large fixed-frame central window with two smaller ones, jutting out to provide additional space and add style and sophistication to your property’s exterior. They can take a long time to install and are costly, ranging from $750 to $2,500.

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Fiberglass Window Prices by Brand

You also have a choice between brands. Some of the leading brands include Pella and Milgard, and each brand has its own prices, specialties, and advantages. The table below shows some of the most popular fiberglass windows and their average costs:

Fiberglass Window Prices by Brand

Fiberglass Window Prices by Brand

BrandAverage Costs (Material Only)
Pella$200 - $1,000
Marvin$200 - $1,500
Andersen$250 - $2,000
Milgard$300 - $1,750

Pella Fiberglass Windows Cost

Pella is regarded as one of the industry’s top manufacturers of fiberglass windows and one of the most affordable. It offers many strong and sturdy designs, engineered for durability and longevity. It sells a range of types in the Impervia line like awning, double-hung, and casement windows to choose from. Prices range from $200 to $1,000.

Marvin Fiberglass Windows Cost

Marvin is another leading provider of high-quality fiberglass windows, with a wide range of models to choose from throughout its Essential and Elevate ranges. You can find small, simple fixed windows from this brand and grand bay windows with beautiful signature designs. The average costs for Marvin fiberglass windows are between $200 and $1,500.

Andersen Fiberglass Windows

Andersen is a popular provider of windows and doors, using various materials in its designs, including fiberglass. Some popular Andersen fiberglass windows can be found throughout the brand’s A-Series lineup, including sash, picture, awning, and casement. Prices for this brand range from $250 to $2,000.

Milgard Fiberglass Windows Cost

Milgard is a provider of very strong, low-maintenance fiberglass windows in many sizes and styles. Designed to work in any climate, these windows are very well-made, with many models to choose from in Milgard’s Ultra Series. However, they are more expensive than other brands, with average prices costing from $300 to $1,750.

Fiberglass Window Glass

When choosing a window, consider the materials, frame type, size, and glass type. Many types of glass can be used in windows, each with pros and cons.

Some types like single-pane are quite simple and affordable but do not provide much insulation. Other types, such as Low-E and triple-pane, can lower your energy bills by trapping heat inside the home in the winter months and reduce the amount of outside noise.

Start by selecting the number of panes, which ranges from single to triple. The more panes you have, the stronger and more energy-efficient your windows are, but additional panes cost more.

After deciding on the number of panes, select between different coatings and add-ons for your windows. Low-E, for example, works to block harmful UV rays that might cause furniture in your home to fade over time and improve energy efficiency. Spectrally selective coatings can block heat while allowing the maximum amount of light into the home, ideally for warm and sunny places.

In general, those who want the most affordable upfront option can opt for simple single-pane windows. You save money over time by choosing at least double-pane windows, and most modern windows are double-pane, typically with a Low-E coating. The table below shows some glass types and average costs:

Fiberglass Window Glass

Fiberglass Window Glass

Type of GlassAverage Cost
Single-Pane$100 - $400
Double-Pane$150 - $600
Reflective Coating$225 - $550
Low-E Coating$350 - $840
Spectrally Selective Coating$350 - $850
Argon Gas$375 - $850
Triple-Pane$400 - $950

Fiberglass Window Installation Cost

Installing a window can be a complicated job, requiring a lot of skill and know-how. Therefore, do not DIY unless you have professional experience with windows. It is best to contact an installer.

They can safely detach and remove the old window, clean and repair the wall and frame for the new installation, and fit the new window in place. They may also have to paint the frame and finish the trim once the window is set.

The time and effort involved in installing a window vary from one job to the next. For example, fitting a small fixed window in place is not as complicated as installing an entire bay window with frame painting and insulation.

This is why costs vary, and it is worth contacting an installer and getting a quote before proceeding. Some charge a flat rate for the entire job, while others charge per hour, at a rate of around $40 to $75 per hour. Many professionals charge a minimum fee of around $150.

Some windows can be fitted in under 2 hours, but others take much longer. In general, fiberglass window installation costs range from $150 to $500 per window, but costs may rise to $1,000 for the biggest jobs like custom bay windows.

Kitchen sink next to new sash windows

Fiberglass Window Insulation

Properly insulating a fiberglass window prevents debris, such as dirt and water, from entering the house. It also keeps air from coming into the house through cracks during winter. Fiberglass windows have great insulation properties. They are manufactured using fibers and resin, two materials that do not expand or contract with temperature changes. This makes them a good insulation window for all seasons. Around the window, a contractor uses an insulation film to ensure there are no cracks between the window and the house. Window insulation film costs $30-$60 per window, including materials used. You can also hire a professional to install a special insulation foam in and around the frame of your fiberglass window, with costs ranging from $50 to $300 for this job, materials not included.

Fiberglass Replacement Windows Cost

In most cases, homeowners have existing windows in place and need them replaced with new fiberglass models. Replacing an existing window is often cheaper than fitting an entirely new one because the hole and frame already exist and do not need to be created. However, the job specifics and amount of work depend on how much cleaning and maintenance is required and how difficult it is to remove the old window and fit the new one. Expect to pay anywhere from $100 to $300 to replace an existing fiberglass window.

Vinyl vs Fiberglass Windows

Many people hesitate between vinyl and fiberglass for a new window. These materials have much in common, such as durability and color and style ranges. However, there are key differences between them.

Fiberglass windows have slimmer frames and wider panes of glass, letting more light into the home and giving you a broader view. They are also more aesthetically pleasing and have slightly better insulation. They are also more durable, able to last for up to 50 years before needing replacement, and do not bend or warp in extreme conditions. However, they are tougher to install, more expensive, and can fade over time.

Vinyl windows are cheaper to buy but can be more costly in the long-term because they are prone to warping and do not last as long, with an estimated lifespan of only around 30 years. They do not need to be painted, are very low-maintenance, and are readily available and easier to fit in place, but they are less effective insulators.

Wood vs Fiberglass Windows

You may also find yourself hesitating between wood and fiberglass windows. There are pros and cons on both sides, and it is important to understand the differences between each type of window.

In terms of costs, fiberglass and wood windows are similar. You can find them at around the same price ranges. At the high end, there are very expensive, elegant wooden windows that are more costly than the most expensive fiberglass models.

Wood may be pricey, but it has the advantage of aesthetics. Many homeowners like the unique look and feel of wooden frames, and you can choose from a wide range of wood types and colors and easily paint and stain them. They can increase your home’s value, but they require more maintenance. Wood is prone to cracks, rot, and other issues that may need repairing.

Fiberglass is more durable and lower-maintenance. You do not need to worry about as many things going wrong with fiberglass as with wood. Fiberglass frames may be better suited to modern, minimalistic homes with their slim frames, whereas wood windows tend to be quite chunky. Fiberglass also lasts longer, with wooden windows often needing replacement in 15-20 years.

Talk to local pros to get quotes for your fiberglass window installation

Enhancement and Improvement Costs

Outdoor Frame Painting

Applying a fresh coat of paint on your window frame makes a great improvement to the appearance. The outside of the frame does not have to be the same color as the inside of the frame. The outdoor frame painting starts with removing the old paint. This can be done with a paint remover solution or sander. Next, apply a primer to the wood and a coat of paint. The average cost of outdoor frame painting is $20-$35 per window. The painting materials cost $40, including a brush, solution or sander, 1 can of primer, and 1 can of paint, and labor fees of $25 per hour for 3 hours.

Old Window Removal

If you already have an existing window and want it replaced with a fiberglass one, you have to have the old one removed first. In many cases, the costs for this are included in the regular labor fee, but you may have to pay a nominal charge of around $20 for the disposal of the old window.

Storm Windows

Storm windows could be an option to consider when having old windows replaced with stronger and more energy-efficient alternatives. A storm window is designed to protect your existing window while also keeping heat inside the home and reducing noise. Costs for storm windows range from $2,000 to $5,000 on average.

Window Screens

Window screens let you open your windows and enjoy fresh air without worrying about bugs. Costs for window screens range from as low as $90 up to $2,000 or more, depending on their size, thickness, and material.

Additional Considerations and Costs

  • Due to the properties of a fiberglass window, expect them to last for up to 50 years.
  • Fiberglass windows are a great option when looking for energy efficiency. The glass fibers in the window do not expand or contract or conduct heat or cold. The frames are also very energy-efficient compared to aluminum and vinyl.
  • Maintenance for fiberglass windows is low. The only maintenance that you may have to provide is repainting. Fiberglass windows may fade or peel over time.
  • In a fire, fiberglass windows have self-extinguishing properties that prevent them from emitting toxic fumes.
  • Fiberglass windows are an eco-friendly choice due to their insulating properties. They help prevent heat loss, so you may not need as much gas or electricity for heating.
  • It is important to get several quotes when looking for fiberglass windows to ensure you are getting the best value because material prices vary from brand to brand. Labor costs also vary depending on who you contact.
  • Fiberglass windows are not at risk of warping or expanding in extreme temperatures like vinyl and wood windows.
  • It is a good idea to get pricing to install fiberglass windows during a contractor’s down season. This is usually during the late fall and early winter. At this time, you may receive considerable discounts.


  • What is a fiberglass window?

Fiberglass windows are windows composed of fibers and resin, materials that do not expand or contract with temperature fluctuations. Fiberglass windows are very popular in the market today due to their many benefits. They increase thermal performance by lowering your energy bills and provide strength, durability, and a beautiful appearance.

  • Are fiberglass windows better than wood?

This depends on your needs and preferences because both wooden and fiberglass windows have their advantages. Wooden windows are more attractive in the eyes of many people, but fiberglass windows last longer and require less maintenance.

  • Do fiberglass windows fade?

Yes, fiberglass windows may fade over time. Repainting these windows may be necessary.

  • Are fiberglass windows energy-efficient?

Yes, fiberglass windows are rated as some of the most energy-efficient windows. They have strong insulating properties and can help keep heat inside the home.

  • Does Pella make fiberglass windows?

Yes, Pella, among other brands, creates and sells a range of fiberglass windows in different types and sizes

Cost to install a fiberglass window varies greatly by region (and even by zip code). To get free estimates from local contractors, please indicate yours.

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