Forum discussion

uPVC Polymer Windows

Hey everyone, HNY!

I'm looking for help in vetting the sustainability cred of uPVC polymer window systems, specifically as an altnerative to traditional PVC vinyl frames. We recenly had a presentation from Intus Windows, who claim that their uPVC frame systems have a low-toxicity profile and excels in performance for thermal efficiency, air infiltration, noise reduction, are low carbon and recycleable --  all while being cost competitve and affordable on mid and high rise applications. They provide EPDs, HPDs, and claim their products are made with low-emitting materials, are free of phthalates, lead, BPA, and have no off-gassing. Instead of using paint, they use high-quality laminates with low VOC emissions.

Does anyone have experience with uPVC as a window frame material? I believe it's common in Europe. One question I have is whether uPVC, which is absent of platicizers (or unplasticized polyvinul chloride/rigid PVC) still emits dioxin during manufacturing or combustion.

Of course, welcome any and all input beyond material health questions -- such as durability, embodied carbon, PHIUS claims, end of life, etc.

Much appreciated. 

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Wed, 01/10/2024 - 02:46

Hi Hilary, These claims have been around for a while but, unfortunately, in terms of the material itself there is no difference between vinyl windows and uPVC windows. It's just a slick attempt at rebranding the material. Plasticizers are never added to vinyl windows, because they need to be rigid. All the fundamental supply chain concerns with PVC are no different. Our article from 2014 is still right on in terms of what those concerns are (and are not)--not much has changed since then, except that we're now more aware of PVC's forced labor issues, and a train derailed in Ohio last winter releasing a lot of vinyl chloride (the highly hazardous monomer that's polymerized to make PVC). That accident helped put vinyl chloride on EPA's hot list for potential TSCA action. Having said that, there are different ways to make a window with PVC, and Intus makes a high quality window. They've dealt with the thermal expansion/contraction issues that cause cheaper windows to deteriorate, and they have great air seals and thermal performance. It's hard to get comparable thermal performance in any other material at the price of vinyl windows, so it's possible that the trade-off is worth considering. I'd love to hear what others think about this dilemma.

Wed, 01/10/2024 - 02:53

Hi Hilary, uPVC has the same chlorine, lifecycle, and social justice concerns (depending on manufacturer) as PVC only without plasticizers. Rigid uPVC requires stabilizers during the extruding process, however, and those aren’t great either. Tough to win with PVC. And their claims about recycling should be taken with a grain of salt (a nod to old PVC marketing!). PVC is a thermoplastic and very recyclable, but it’s complicated.  Europe probably manages that process better than here. Unless the company says they will take them back at end of life, it is very unlikely an old PVC window is going to be recycled in the U.S. With all that said, a PHIUS uPVC window does offer impressive performance for the cost. I understand why people choose them. Brent From

Wed, 01/10/2024 - 14:57

I don't believe it is ethical to use a material that is "cost competitive" because it uses forced or slave labor and causes cancer to marginalized black and brown communities (see many articles written about "Cancer Alley ") no matter how much energy it saves. At the Design for Freedom summit, they asked architects if we are still willing to take the "slavery discount." Having said that, I understand that it may be oversimplifying to assert that ALL vinyl products do this. But, I would place the burdern of proof that they are NOT engaged in these unethical practices upon your manufacturers, before you select any vinyl products. Don't get me started on microplastics in our watersheds/oceans. You may have guessed that I am firmly against PVC or uPVC windows, the more I read about them, the more I am convinced that they have got to go.

Wed, 01/10/2024 - 16:52

Appreciate the input. Our firm as a whole aims to eliminte PVC in our projects and I've personally been on a mission to strike it out for many years, but alas, it comes down to owner decision making. When vinyl windows are the basis of design for a good number of affordable housing developers due to immense scrutiny over cost containment, the sustainability moves are often incrementally towards 'less bad' -- thus my curiosity about the science behind Intus' claims. Thanks for the clarification, Brent and Nadav, about the consituetive ingredients and essential 'rebranding'. That was my gut sense.  Douglas, 100%. The numerous social-environmental injustice aspects would seem to resonate and convince most affordable housing developers, but that's not been my experience to date having sat on both sides of the table.

Wed, 01/10/2024 - 17:02

We have used UPVC windows on a number of projects, most of them Passive House.  From an energy/cost perspective they are great, and since out projects are affordable housing with tight budgets, we probably could not do Passive House without them.  I cannot comment on the health manufacturing issues.  I would note that a bonus (probably small) is that Intus plants a tree for every window installed.

Wed, 01/10/2024 - 17:23

Yeah, we are certainly no apologists for PVC! BG has covered these repeatedly over the years (most recently here). Our petrochemical plastic world is a complicated mess, and fenceline petrochemical impacts come from more than PVC (though that industry has had more than its share of issues!). Our entire material lifecycle is hard to untangle. Phones, computers, batteries, PV. All huge energy and material health problems that come with tradeoffs, including serious social justice concerns. With PVC that complication is sodium hydroxide, which is used to make almost everything in the consumer and built environment (metals especially). Chlorine is a direct byproduct of sodium hydroxide production (think separating NaCl). And the world uses a lot of sodium hydroxide. Hence, there is a lot of chlorine and a lot of PVC. I’m not saying that is a good thing or that PVC is the right “sink” for excess chlorine. We’ve long recommended against the use of PVC and looked for alternatives, but the brutal truth is our banning of PVC is unlikely to change the sodium hydroxide/chlorine production world. We can, however, try to hold manufacturers responsible, as we have done with getting phthalates out of vinyl and reducing fenceline emissions from the early days of PVC. It's a mess, and there are no perfect materials/products, but we’ve already had a positive impact on the vinyl world, so keep fighting the good fight! Brent From: Hil

Wed, 01/10/2024 - 21:05

I understand that once we start looking into the supply chain, it can be discouraging that there are no good options. I agree that it is important that we strive for better, when we can't get perfect. But when forced labor is a possibility, I think we have a duty to investigate and ask questions as much as possible. When PVC is cheap and suppliers can't tell us why, there is likely a reason that we won't like. For now, I am still specifying PVC when it is absolutely required by a use or a client, but I am no longer using it when it is just convienent. I also try to educate clients about the health and social justice risks of PVC. We know that PVC with phthalates cause liver damage, cancer, endocrine damage in humans, but as far as I can tell, the jury is still out on whether non-phthalate vinyl windows leach toxic chemicals into homes. Hopefully the recently initiated EPA study will tell us more. 
https://www.epa.gov/newsreleases/epa-begins-process-prioritize-five-chemicals-risk-evaluation-under-toxic-substances    

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