Enter your zip to
find local pros.

Fiberglass Window Frames

Compare quotes from up to four local home service companies.
Where do you need the window installer?
Please enter a valid zip code

Free quotes. No obligation.

Fiberglass Replacement Windows

Fiberglass replacement windows are known for being durable and waterproof. They come with many of the benefits of wood or aluminum frames, but they’re budget friendly for homeowners who are looking to cut costs on window replacements. Here are some quick benefits of fiberglass windows:

    • Will not crack
    • Will not peel
    • Will not bend or warp
    • You can paint fiberglass windows
    • Wood window like profile
    • Available with wood clad interior
    • Energy efficient options
    • Will not get stuck due to expansion and contraction from heat or cold

best replacement windows chart


Benefits of Fiberglass Frames

  • Durability: Fiberglass is one of the most durable materials used to construct windows today. Frames don’t have to be thick to provide strength and stability. Fiberglass resists weathering effectively, and the material lasts for up to 80 years according to the Pultrusion Industry Council.
  • Design: Fiberglass can be painted at a factory location or in person by the homeowner or a contractor. This makes it simple to get fiberglass windows in any color.
  • Weather-resistant: Both fiberglass and glass expand and contract at a similar rate, making fiberglass an ideal material for window construction. Vinyl windows expand and contract about seven times as much as glass, and wood about three times. These are big differences that can lead to frame failures over time. Because fiberglass expands and contracts with glass, it helps protect the window from temperature changes over time.

Blue and red fiberglass frames

Fiberglass Window Frames are Energy Efficient

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 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, which prevents drafts.

Fiberglass is a Sustainable Window Product – Eco Friendly

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

Cons of Fiberglass Window Frames

  • Aesthetic: Some people think fiberglass frames lack the traditional charm of wood windows. To compensate, homeowners can install an interior wooden trim on the fiberglass frame.
  • Lacking energy efficiency: Most fiberglass window frames are hollow inside, which reduces their energy efficiency, but frames with foam insulation effectively increase the frame’s energy efficiency without being prohibitively expensive.

If you’re looking for a durable product that’s going to outlast vinyl—and possibly aluminum and wood windows—fiberglass frames are a good option to consider. The windows are strong, affordable, and designed to hold their seals effectively.

Fiberglass Replacement Window Brand Manufacturers List:

You may also be find these fiberglasswindow installation retailers helpful:

fiberglass windows

Are Fiberglass Windows the Best Replacement Window Option?

When shopping for fiberglass windows, it’s important to find what your priorities are when choosing a replacement window for your home. These window reviews may also be helpful in making your decision:

Here are some other helpful pages to help you through your replacement window project.

Cost for Window Replacement

Measuring Replacement Windows 

Standard Window Sizes

Types of Window Frames

When to Replace Windows 

Window Glass Repairs 

Window Rebates & Incentives 

Window Replacement Information

Let us help you decide what type of replacement window you should choose for your window installation project below: 


Compare All Types of Windows 

Ready to get free quotes from local contractors?