Steel vs uPVC: Why craftsmanship outlasts trends

• 19 May 2025
• News

The choice of a new window often involves weighing up three elements: looks, price and convenience. And while looks and price are undoubtedly important, it is convenience that is regularly king. We need the job doing, and we need it done quickly.

Which is why uPVC is a popular choice across the UK, largely thanks to its low cost and quick installation. But if you are weighing up steel vs uPVC windows for a premium property, heritage restoration or high-spec new build, price should not be your only consideration. The real question is: do you want a short-term solution, or something crafted to last?

The case for uPVC – and its limitations

Let’s begin with the benefits. uPVC is relatively inexpensive. It’s lightweight, low maintenance and available in a range of standard colours and window types, including bay windows and casement windows. For volume housebuilders, it often ticks the right boxes.

There are, however, clear drawbacks. While uPVC windows can offer a degree of insulation, they typically fall short on strength, design flexibility and, crucially, longevity. Over time, uPVC can discolour, warp or become brittle, especially when exposed to fluctuating temperatures and UV light. Frames may expand and contract with heat, affecting airtightness and increasing energy costs. In short, while uPVC suits short-term needs, it lacks the durability or elegance demanded by discerning homeowners and developers.

Why steel stands apart

In contrast, steel window frames have earned their reputation over many decades. Crittall Windows’s W20 TE system is the latest evolution in this story, offering modern functionality within a classic form. The frame’s steel core brings exceptional strength, allowing for slim sightlines and larger panes of glass that maximise natural light and improve ventilation. For projects that demand minimal visual disruption, including listed buildings, this is the best option.

What truly sets W20 TE apart is its thermal performance. Historically, steel windows were seen as ‘cold’. No longer. With UW and UD values of just 1.4 W/m²K, W20 TE competes directly with thermally broken aluminium frames and insulated wooden windows. It is fully compliant with Approved Document L, making it a standout for energy efficiency in heritage and new-build projects alike.

Unlike uPVC or even aluminium windows, steel will not warp, crack or rust when properly finished. W20 TE frames are galvanized and polyester powder coated for maximum weather resistance. This ensures excellent insulation and low maintenance, and contributes to a working life well beyond 60 years.

From a sustainability perspective, steel is also the more responsible choice. W20 TE is made from 100% recycled material and, unlike uPVC, it retains its integrity and function over the long term. That kind of durability translates into fewer replacements, less waste and reduced environmental impact.

If you are comparing steel vs uPVC windows, remember this: uPVC might follow trends, but steel defines them. Crittall’s steel windows offer strength, style and performance that not only meet modern standards but elevate the architectural integrity of any building – from listed townhouses to cutting-edge developments.

In the end, craftsmanship lasts. Plastics do not.

• For more information about Crittall’s windows and doors, contact us here.