Fiberglass vs Vinyl – Which Type of Window is Better?

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The best thing about answering this question is that it’s pretty much a win-win. It’s like asking, “Which is better? A warm, sunny day, or a beautiful sunset?” You just can’t go wrong with either! Let’s compare and contrast fiberglass and vinyl windows in order to help you better decide for yourself.


For reasons that will be detailed below, fiberglass windows can cost as much as 30% more than vinyl windows, installed. First, fiberglass material costs more than vinyl material. In addition, the installation costs of fiberglass are normally higher than the installation costs of vinyl windows. The reason for this is that fiberglass material is less flexible than vinyl, and it takes more time and labor to fit the windows into the framing.


Fiberglass wins this contest, hands down, being around eight times stronger than vinyl. Fiberglass, by definition, has glass fibers embedded in the plastic resin. This adds strength and durability to the frame. While you can expect new vinyl windows to last up to 30 years, you can expect fiberglass windows to last up to 50 years! That difference is significant. But also ask yourself if you expect to be in your home 30 years from now.

Energy Efficiency

Once again, fiberglass wins this contest. Fiberglass does not conduct heat or cold, making it overall a better insulator than vinyl. Also, since fiberglass is stiffer and more durable, it will not warp (due to excess heat) or expand and contract like vinyl windows. This expansion and contraction and/or warping of vinyl can, over time, lead to poor air seals. For these same reasons, fiberglass windows offer better insulation against noise than vinyl windows.

Color Availability/Appearance

Both vinyl windows and fiberglass are available in many pre-baked colors. The color runs throughout the entire material. The one difference is that vinyl window frames cannot be painted, if you choose to change your color schemes. Fiberglass, on the other hand, can be painted over. One other thing to note is that fiberglass windows are closer in appearance to wood, while vinyl is “plain” or smooth.


Both vinyl and fiberglass windows are essentially maintenance free. They can be easily wiped down with a damp rag. But do keep in mind that if you buy fiberglass windows and paint them, you will likely need to eventually scrape and repaint them.


The return on investment for vinyl windows is around 75%, which is amazing! Fiberglass windows likely come in with a higher ROI, but there is not a lot of data that gives us this information yet.

The reality is that for most people, vinyl wins. Vinyl windows are more affordable, for sure. Yes, vinyl can expand and contract and/or warp unlike fiberglass, but when fitted right, such issues are greatly minimized. And what about the better energy efficiency afforded by fiberglass windows? While the difference in energy efficiency between fiberglass and vinyl windows is not meaningless, it is negligible.

Compare for yourself! It is a win-win choice – like choosing between a sunny day or a beautiful sunset.