Composite vs Fiberglass Windows

Replacement Windows Reviews

Home : Recommendations : Composite vs. Fiberglass Windows

Composite vs Fiberglass Windows

Let's compare composite vs fiberglass windows in four key areas: overall strength, aesthetics, energy efficiency, and costs. By comparing and contrasting, hopefully you will have a better understanding of which frame material might be right for your window replacement project.

Bottom Line: The bottom line on composite vs fiberglass windows is that it's extremely dfficult to make generalizations because each composite is very specific to the company that manufacturers the windows. See our page on the best composite windows for pricing on some of the top models.

Dane - Site Editor - - Page Last Updated: March 14, 2024

Connect with Local Window Companies

Marvin Elevate Cost: $$$$$
(5 out of 5)

Get Our Recommended Window List

Also please consider filling out the free form on our site for 3 quality window price quotes — it’s how we afford to provide free consumer information. We’re not incentivized by ANY company and will help you with ANY questions you might have, and help you navigate ANY bids you receive. That’s our guarantee to you!


On the strength front, composite materials and fiberglass windows will be quite similar. Fiberglass composites will be a bit stronger than a vinyl composite. The best answer is that it will depend on the model and upgrades selected for that particular window.

Andersen 100 window


The overall look of fiberglass is an upgrade over vinyl, but is pretty similar to many composites. For instance, the Marvin Infinity is regarded as a very best looking fberglass windows, while the Pella Impervia does not get good marks for how it looks. The Andersen 100 composite and Starmark from Okna are regarded as nice looking windows, while the Amsco Renaissance is a cheaper model and can't really compete against these other models.

Energy Efficiency

Fiberglass is going to be more energy efficient over many composites. However, top performers like the Okna Starmark offers excellent performance numbers, which you will pay for. In the long term, fiberglass windows will be a better performing for your home and energy bills.

Costs & Value

Fiberglass will typically be a bit higher than composites - see our page on the best fiberglass windows to see some of the costs and prices for many of these models. Composites have a wider cost range that starts lower than their fiberglass counterparts.

Renewal By Andersen Reviews

Back To Quick Links ˆ

Related Topics: Composite vs Wood

Vinyl vs Fiberglass Windows

Private Policy