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Community and Q&A

PVC vs. uPVC Windows

Michael Maines | Posted in General Questions on

I have often heard high-performance window manufacturers tout that their uPVC–unplasticized polyvinyl chloride–is a “greener” material than PVC–i.e., plasticized polyvinyl chloride. I understand the reasoning but can’t find proof that more typical North American window manufacturers use PVC and not uPVC. It doesn’t seem logical to use a flexible material when a more-rigid material can work. Exceptions might be vinyl-wrapped wood frames, such as Anderson 400 series, but for typical replacement windows and other low-cost vinyl windows, are the frames made from uPVC?

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  1. jonny_h | | #1

    My (non-expert) understanding is that PVC (or "vinyl") is just polyvinyl chloride -- not necessarily plasticized -- which may or may not have a variety of other additives depending on application. PVC drain pipes and electrical conduit aren't, I imagine, plasticized -- though some have added UV stabilizers and such. I think the uPVC thing is mostly marketing -- "Our PVC is better than the other guy's PVC because we call it something different" -- but it may be impossible to tell for sure without knowing the exact composition of the resin each manufacturer uses.

    Some manufacturers do use something a bit different -- REHAU RAU-FIPRO is a fiber-reinforced PVC, which is allegedly a stronger product halfway between fiberglass and plain PVC.

    1. Expert Member
      Michael Maines | | #4

      Thanks Jonny, good points about different additives other than plasticizers, and about fiber-reinforced PVC.

  2. oberon476 | | #2

    Vinyl, PVC, uPVC for windows are different descriptors for the same product; possibly excepting some hybrids as Jonny pointed out.

    I have never looked into it, but my impression is that it was certain European window companies (and their fans) who started the whole "my windows are better because we use uPVC and not vinyl" thing as a marketing tool since vinyl is more of a North American term and uPVC is more common elsewhere., and uPVC sounds cooler.

    But while standard vinyl windows may all use unplasticized material, that doesn’t mean all vinyl used in windows is created equal. There are other factors to consider, above snd beyond basic performance. The vinyl used in some windows is simply a lot better quality that the material used in others.

    1. Expert Member
      Michael Maines | | #3

      Greg, I appreciate your reply--I know that you know windows!

      Your thoughts on PVC vs uPVC match what I had surmised after some research. Good point that even among different windows, PVC (or uPVC) quality will vary.

  3. jackofalltrades777 | | #5

    I also wonder now with the 60+ ships waiting to doc & unload at the US ports. What are lead times with Euro windows like Zola? I was told by someone around 4-6 months due to port shipping issues.

    1. Expert Member
      Michael Maines | | #6

      We just ordered PVC windows from Europe--lead time 18-20 weeks, a recent change from 12-14 weeks.

  4. GBA Editor
    Martin Holladay | | #7

    Here's what I wrote on this issue back in 2015:
    "The terms "uPVC window," "PVC window," and "vinyl window" are all interchangeable. When manufacturers brag that their windows are made of "uPVC," they are muddying the waters rather than clarifying the issue. All vinyl window manufacturers use similar vinyl. It's all the same stuff."

    (The quote is from this Q&A thread.)

    1. Expert Member
      Michael Maines | | #8

      Thank you, Martin--I'm not sure why that didn't come up in my many searches here.

  5. Expert Member
    BILL WICHERS | | #9

    The way I usually explain it to people is that plasticizers modify the material to make it more flexible (more “plastic”) than it would be in its natural state. PVC wants to be pretty rigid, like PVC pipe and conduit (which aren’t plasticized). If you want to use PVC for something like an extension cord, which needs to be flexible, you have to add plasticizers to make it flexible. I don’t know why a rigid window frame would need to have plasticizers added to the PVC.

    Note that it’s usually the plasticizers that are least stable chemically in plastic compounds, and if/when they degrade or leech out that’s when the plastic gets hard and brittle, and usually starts to crack. That only applies to plastics that have plasticizers added though. This is why old PVC insulated extension cords tend to get hard. A lot of advancement has been done in regards to plasticizers though, so modern materials are much more stable and hold up better over time.

    There’s some explanation. I’m with Martin in regards to there probably be little if any difference in the materials the windows manufactures are actually using in their products. All those window companies are just buying the PVC resin from chemical companies like Dow or DuPont anyway — none of them make their own plastic resin, they just extrude it from raw materials they buy from their suppliers.


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