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Replacing Fiberglass Windows

Average cost range:

$588 - $950

The average cost to install a standard double hung fiberglass window ranges from $588 to $720 per window. Replacement costs can go up to $950 for higher end window styles, including the cost of installation. Fiberglass windows are usually more expensive than vinyl windows (which average $350 to $585 per window).

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Fiberglass Replacement Windows

Fiberglass replacement windows are known for being durable and waterproof. They come with many of the benefits of wood or aluminum frame replacement windows, but they are more affordable for homeowners who are looking to cut costs on their window replacement project. Fiberglass replacement windows will not crack, peel, bend, or warp. Fiberglass windows are a great option if you are looking for energy efficient replacement windows. Unlike wooden windows, fiberglass windows don’t deal with getting stuck due to heat expansion and contraction like aluminum windows.

fiberglass bedroom windows

Benefits of Fiberglass Windows

  •  Fiberglass is one of the most durable window materials used to construct frames today. These window frames do not have to be thick to provide strength and stability. Fiberglass frames resist weathering effectively, and the framing material lasts for up to 80 years.
  • Fiberglass window frames can be painted at a factory location before installed or in person by the homeowner or a window contractor. This makes it simple to get fiberglass windows in any color to fit your needs.
  • Fiberglass windows and glass panes expand and contract with heat at a similar rate, which makes them an ideal material for window construction. A vinyl window expands and contracts about seven times as much as glass, and replacement wood windows contract about 3 times as much. These are big differences that can lead to window frame failures over time. Since fiberglass frames expand and contracts with glass, it helps protect the window from temperature changes over time.

What to Consider Before Installing Fiberglass Windows 

  • Some homeowners prefer the look and charm of new wooden windows in comparison to fiberglass frames. In that case, a homeowner could install an interior wood trim on top of the fiberglass frames to combine strength and aesthetics into one with a replacement clad wood window.
  • Most fiberglass window frames are hollow inside, which reduces their energy efficiency. However, frames with foam insulation effectively increase the frame’s energy efficiency without being prohibitively expensive. You may want to discuss with your window installation contractor if you can get your fiberglass window with foam insulation.


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Best Brands for Fiberglass Windows

Most of the top window brands offer fiberglass replacement windows as they are one of the top choices for window installation amongst homeowners as well as vinyl and aluminum window installation.

Choosing the right brand for your window replacement is an important part of buying new fiberglass window. A great brand will offer you quality options when it comes to window framing materials, the best warranties, and stylish fiberglass window designs that can’t be found elsewhere.

Check out our list of the best window brands to help you find replacement fiberglass windows in your area and the cost for window replacement associated with them.

Fiberglass Windows vs. Vinyl Windows

Fiberglass windows are arguably more sustainable than any other window frame on the market. After all, more trees can be grown and harvested for wood window frames. However, when demand is high, it’s much easier to simply convert sand to fiberglass.

best replacement windows chart

However, fiberglass windows look very similar and cost more than vinyl windows.  Fiberglass windows are eco friendly and it also takes less energy to create than aluminum, wood, or vinyl window frames. These days, fiberglass is being recycled. This makes the waste from the windows less of an issue, since it can be used in cements and other applications.

fiberglass windows

Energy Efficient Fiberglass Windows

Fiberglass is an excellent insulator, which is why so many homeowners use fiberglass insulation in their homes. This same insulator quality is what makes fiberglass windows so energy-efficient. Fiberglass windows can be foam filled for even higher levels of insulation. They’re known for expanding and contracting at the same rate as the glass they hold. This prevents drafts and saves you money on utility bills in the long run.