Aluminium vs uPVC Windows

Choosing between aluminium and uPVC windows is one of the most common decisions homeowners face during a renovation. Both materials have improved significantly over the past decade, but they still have distinct strengths and trade-offs. This guide compares them across the factors that matter most — appearance, thermal performance, security, durability and cost — so you can make a confident choice.

Appearance

Aluminium frames are significantly slimmer than uPVC, which means more glass and a cleaner, more contemporary look. A typical aluminium frame is around 50-65mm wide, while a uPVC frame is usually 70-80mm or more. This difference might sound small on paper, but it's noticeable in person — especially on larger windows or floor-to-ceiling glazing.

Aluminium is available in virtually any RAL colour and can be finished in matt, satin or gloss. Dual-colour options are common, allowing a different colour inside and out. uPVC has improved in recent years with foiled finishes that mimic wood or anthracite grey, but the range is still more limited and the finish can look less refined up close.

Thermal Performance

Modern aluminium windows use thermally broken profiles — an insulating barrier within the frame that prevents cold transfer. This means they now achieve U-values comparable to uPVC, typically around 1.2-1.4 W/m2K with double glazing. uPVC windows have always been good insulators due to the material's low conductivity, and they achieve similar U-values at a lower price point.

With triple glazing, both materials can achieve U-values below 1.0 W/m2K. In practice, the thermal performance difference between a quality aluminium and uPVC window is negligible — it comes down to the glazing specification and the quality of installation rather than the frame material alone.

Security

Aluminium is inherently stronger than uPVC, which gives it a natural advantage in terms of forced-entry resistance. Most aluminium window systems are PAS 24 certified as standard. uPVC windows can also achieve PAS 24, but they often require steel reinforcement within the frames to do so. Both materials are available with multi-point locking systems and laminated glass options.

Durability and Lifespan

This is where aluminium pulls clearly ahead. Aluminium windows have an expected lifespan of 40-50 years. The powder-coated finish is UV-stable, scratch-resistant and won't peel, flake or discolour. uPVC windows last around 25-30 years. While they're low-maintenance, they can yellow, warp or become brittle over time, especially in south-facing positions with prolonged sun exposure.

Cost

Aluminium windows cost approximately 20-40% more than uPVC. For a standard three-bedroom semi, a full set of uPVC windows might cost £4,000-£6,000 installed, while the equivalent in aluminium would be £6,000-£9,000. The premium reflects the material cost, the precision manufacturing involved, and the longer-lasting finish.

When you factor in the longer lifespan and virtually zero maintenance, the cost per year of ownership is often comparable. Many homeowners find that aluminium represents better value over a 30-40 year period, even with the higher upfront cost.

Which Is Right for You?

If your priority is kerb appeal, longevity and a premium finish, aluminium is the clear choice. It suits modern builds, extensions, and any project where slim frames and maximum glass area matter. If you're working to a tighter budget and need solid performance without the premium price tag, uPVC remains an excellent option — especially for like-for-like replacements in traditional properties.

At Vitrum Solutions we install both aluminium and uPVC windows and are happy to advise on the best option for your home, style and budget. There's no pressure to go one way or the other — we want the right product in the right place.

Frequently Asked Questions