uPVC vs Aluminium Windows: Which Is Right for Your Home?

If you're replacing windows, the uPVC vs aluminium question is usually the first big decision you'll face — and the honest answer is that neither one is "better" outright. They're suited to different priorities. Here's how they actually compare.

Cost

uPVC is the more budget-friendly option, typically 20–40% cheaper than aluminium for a comparable window. That gap comes down to raw material and manufacturing cost — aluminium requires more complex extrusion and a thermal break to stop heat transfer through the frame, both of which add cost.

If budget is the primary driver, uPVC will almost always win. If you're working with a supplier who imports direct from the manufacturer rather than through several layers of distribution, that price gap on aluminium narrows considerably — worth asking your supplier where their stock actually comes from.

Thermal Performance

uPVC is a naturally poor conductor of heat, which makes it easier to hit strong U-values (a measure of heat loss — lower is better) without much engineering. Well-specified uPVC windows regularly achieve U-values around 0.8–1.0 W/m²K.

Aluminium conducts heat far more readily, so it depends entirely on the quality of the thermal break built into the frame. A cheap aluminium window will underperform uPVC on insulation. A well-engineered one, with a proper polyamide thermal break, can match or beat it. This is the single biggest thing to check if you're comparing aluminium options — ask for the U-value, not just the frame material.

Maintenance & Lifespan

uPVC needs almost no maintenance beyond an occasional wipe down — it won't rust, rot, or need repainting. It does have a practical lifespan (typically 20–30 years) after which it can look tired even if it's still functioning.

Aluminium is more durable long-term and resistant to warping, making it a better fit if you want a 30–40+ year window and don't mind the higher upfront cost. It also holds paint finishes better if you ever want to change the colour down the line.

Style & Sightlines

This is where aluminium has a clear edge. Because it's structurally stronger, aluminium frames can be made much slimmer than uPVC for the same size of window — meaning more glass, less frame, and a cleaner, more contemporary look. This matters most for larger openings, bifold doors, and anywhere you want an unbroken view.

uPVC frames are inherently chunkier because the material needs more bulk to achieve the same structural strength. For traditional or period-style properties this often isn't a downside, but for modern extensions or large glazed areas, it's worth seeing both in person before deciding.

Which Should You Choose?

• Budget is the priority, or the property is more traditional in style → uPVC
• You want the slimmest possible sightlines, a longer lifespan, or you're on a large modern glazing project → aluminium, provided the thermal break is properly specified
• You're not sure → ask to see U-values and BFRC ratings side by side rather than relying on the frame material alone — that's the number that actually tells you how the window will perform

A Note on Where Your Windows Come From

Most of the price difference between suppliers isn't the window itself — it's how many hands it passes through before it reaches you. Window Supply sources directly from Drutex, one of Europe's largest window manufacturers, cutting out the import middlemen that inflate typical UK pricing. That's true whether you're going uPVC or aluminium.

Want a straight comparison for your specific project? Get a quote and we'll give you real U-values and pricing for both options side by side.