Fibrex vs Vinyl Windows

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When it comes to fibrex vs vinyl windows, there are a number of factors to consider. First off, let’s discuss what these materials are. Fibrex is the name of the frame used by Renewal by Andersen and the Anderson 100 series window. Essentially, fibrex is a composite material, which is a combination of vinyl and wood. In terms of the wood, fibrex is essentially wood shavings that are integrated into the vinyl extrusions. The result, according to Anderson, is a more durable and stronger window frame. How much stronger? I think this is a matter of debate.

On the other hand, vinyl is made from PVC or polyvinyl chloride (that's a mouthful, right?). PVC has been around for a long time. In terms of the fenestration industry, vinyl has been used to make windows for over three decades. When it first came out, there were issues with the overall strength of the material. The transition from PVC to uPVC (unplasticized PVC) did alot to change that and strengthen the material. Additionally, vinyl windows don't rot or mildew, and do not conduct (much) heat or cold. Over the past several decades, manufacturers have continued to make advances that make vinyl ideal for replacement and new construction windows and doors.

Review By John M. - Site Editor - Updated In 2025

Vinyl Windows Cost vs Fibrex

Pound for pound, vinyl windows cost are less than fibrex prices. However, this does need some clarification. For instance, the Andersen 100 series, which uses the fibrex frame and is sold through Home Depot stores, will cost less than say the Okna 800 series or the Vytex Fortis window. Having said that, there aren't a ton of vinyl windows out there that are more expensive than even the Andersen 100.

Furthermore, there are no vinyl windows that are more expensive than Renewal By Andersen prices. In fact, Renewal pricing is some of the most expensive in the industry, rivaling and beating many wood clad windows like Andersen Windows 400 Series prices and Marvin wood windows. Fibrex should be thought of as more expensive than vinyl.

History Of Fibrex vs Vinyl Windows

Vinyl's first advance was the transition from PVC to uPVC. UPVC differs from PVC in that it does not contain plasticizers, making it less flexible, stronger and more resilient - in a word, ideal for window frames. Another advance over the past two decades, has been the addition of different materials to the vinyl in order to strengthen the final product. In some sense, what happened in the vinyl window market is nearly identical to the Andersen windows using wood to strengthen their window frames. More of less just a different name.

Fibrex is a proprietary name that goes under the general heading of a composite window frame. Other manufacturers call their window frames engineered vinyl. Really there’s no difference between the two, although what is used in conjunction with that you PVC or vinyl is different. For instance, Anlin Windows And Doors uses small flecks of titanium to create a frame that is stronger than simply using straight uPVC.

Aesthetics And Performance

When looking at fibrex vs vinyl, I think the thickness of the window wall or frame is the more important issue that most manufacturers would like to minimize. Fibrex is often thinner than vinyl and is therefor a very nice looking material. Fibrex is clearly the window in terms of the overall aesthetics.

However, when you look at the performance data of the Renewal By Andersen or the Anderson 100 series, both of which are made from fibrex, they can’t touch the top 30 vinyl windows in terms of performance data. This means that top vinyl windows will get lower air infiltration rating, lower U-values, and better DP or design pressure ratings. Vinyl is clearly the winner over fibrex in terms of energy efficiency.

Fibrex vs Vinyl Windows On Strength

So which is stronger, fibrex or vinyl? I would say that fibrex is the stronger material over a vinyl that has no other additives. And this is an important point because many top-tier vinyl manufactures have ways to create a stronger mainframe. So, in the cases of additives, it’s unclear which material is going to be the strongest.

Let me be clear on one point; in the residential market, this is kind of a moot point. Here’s the reason. Any mid range or top tier vinyl window is plenty strong for 95% of all window openings. Windows are not loadbearing. Instead, they are placed inside of an opening in the wall that is surrounded on all four sides by a wood frame. It is this frame that is bearing the load and not the window itself.

Now, I said in 95% of all cases. In the remaining 5%, we might be talking about a very wide opening in which cheap vinyl windows could bow overtime if the window can’t support its own weight. This is where a good window wrap or installation team comes in quite handy. Anyone worth their salt would advise that they use two windows side by side to handle the span. This would provide a long-term solution that wouldn’t end up causing big problems.