Does Acrylic Block UV Light?

Yes, to a meaningful degree: Retro Panes improve the UV-blocking performance of your windows, though it's worth understanding exactly what that does and doesn't mean before you rely on it.

A Quick Primer on UV

Ultraviolet light is generally split into three bands: UV-A (the longest wavelength, closest to visible light, and the main contributor to long-term fading), UV-B (shorter wavelength, higher energy, and the more aggressive of the two when it comes to breaking down materials), and UV-C (the shortest and most energetic, but almost entirely filtered out by the atmosphere before it reaches ground level, so it's rarely a practical concern for home glazing).

When people talk about a window "blocking UV," they usually mean UV-A and UV-B specifically, since those are the two bands that actually reach your living room and do the damage to furniture, flooring, and fabrics over months and years of exposure.

What AKRYLON® Actually Blocks

Our Retro Panes are made from acrylic (PMMA), branded AKRYLON®, manufactured in Slovakia by 3A Composites. PMMA's molecular structure naturally absorbs a significant portion of UV-B radiation without needing any special additives; this is a property of the material itself, not a coating that can wear off or need reapplying.

This matters day-to-day because UV-B is one of the main drivers of fading in furniture, flooring, and fabrics that sit near a window. A sofa, rug, or set of curtains that spends years in direct or indirect sunlight is constantly absorbing UV energy, and it's this energy that gradually breaks down dyes and pigments, leading to that washed-out, faded look.

Industry sources on acrylic performance commonly describe this as an advantage over ordinary glass specifically on UV-B: even standard-thickness acrylic tends to block the majority of UV-B rays through its chemical structure alone, whereas standard, untreated glass is generally described as a comparatively weaker UV-B barrier. We'd flag this as a widely-repeated industry comparison rather than something we've independently tested on our own panes. If you want a guaranteed, certified transmission figure for your specific project, that's worth asking us for directly rather than assuming a generic industry number applies exactly to AKRYLON®.

What It Doesn't Fully Block

Here's the honest picture: while standard AKRYLON®, still blocks a solid amount of UV overall, it isn't a specialised UV filtering product, so it won't offer the near-total protection that dedicated UV-filtering glass provides. For everyday furniture, flooring and fabrics, that level is more than sufficient, but if you're protecting something genuinely high value, like original artworks, museum-grade prints, we'd always recommend pairing Retro Panes with a dedicated UV-filtering solution rather than relying on standard acrylic alone.

How This Compares to Other Options

It's worth knowing where standard acrylic like ours sits relative to the alternatives, since "UV-blocking" products vary a lot:

•    Standard window glass: Generally blocks a good portion of UV-B, but is often a comparatively weaker barrier overall, and quality varies significantly by glass type.

•    Acrylic: Blocks a meaningful portion of UV-B through the material's own chemistry, but still allows a notable amount of UV-A through.

This spectrum matters because it shows that "acrylic" isn't one single answer to UV protection; it depends entirely on the specific formulation. Retro Panes sit in the middle: a genuine, natural improvement over no secondary glazing at all, without being a specialist UV-filtering product.

UV Blocking is a Different Question From UV Stability

It's worth being clear that UV blocking (how much UV passes through) and UV stability (whether the material itself degrades from UV exposure) are two entirely different properties. AKRYLON® is UV-stable: it won't discolour or become brittle from continued sun exposure, regardless of the UV-blocking discussion above. We've written a full breakdown of that separately, including why older acrylic used to yellow and why modern AKRYLON® doesn't.

Read the full explanation: Does Acrylic Yellow Over Time?

A Note on How UV Claims Are Usually Tested

For readers who want to understand the underlying testing methods rather than just take manufacturer claims at face value: UV transmission is typically measured using a spectrophotometer, which passes light of specific wavelengths through a sample and records exactly how much energy makes it through versus how much is absorbed. This produces a transmission curve across the UV-A, UV-B, and visible spectrum, rather than a single blanket percentage. Reputable manufacturers of dedicated UV-filtering products will usually be able to show this kind of curve on request, which is a good way to sanity-check any UV claim, including the general industry comparisons referenced on this page.

The Short Answer

Retro Panes give you genuine, natural UV-B reduction as a property of the acrylic itself, plus real insulation and noise benefits. But for guaranteed, fully-tested UV-A protection, such as for valuable or irreplaceable items, pair them with a dedicated UV-filtering solution rather than relying on the panes alone.

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