uPVC and aluminium are the two materials most UK homeowners actually choose between in 2026 (timber sits apart as a heritage option). The short version: uPVC is the value pick at £400 to £1,000 per window fitted, while aluminium runs £550 to £1,300, roughly 30 to 40% more, and buys you slimmer frames and a longer life. Below we compare them across five dimensions that matter, then give a verdict. If you already know which way you are leaning, the uPVC window calculator and the aluminium window calculator will price your own house.
The headline comparison
Before the detail, here is the side-by-side picture. The figures are fitted, per-window ranges for a standard casement, the style most homes use.
| Dimension | uPVC | Aluminium |
|---|---|---|
| Cost per window (fitted) | £400–£1,000 | £550–£1,300 |
| Price vs uPVC | Baseline | Around +30 to 40% |
| Lifespan | 20 to 25 years | 30 to 40 years |
| Frame sightlines | Chunkier | Slim, more glass |
| Maintenance | None | None |
| Thermal performance | 1.0 to 1.4 W/m²K | 1.0 to 1.4 W/m²K |
Source: DGCC 2026 dataset (Checkatrade, StayWarm). Aluminium uplift around 30 to 40% vs uPVC.
Cost
Cost is the clearest difference. A fitted uPVC casement sits in the £400 to £1,000 band, while the same window in aluminium is £550 to £1,300, an uplift of around 30 to 40%. On a ten-window house that gap can mean several thousand pounds, so aluminium has to earn its premium on looks or longevity rather than performance alone. uPVC remains the entry point to A-rated glazing.
Best Buy uPVC for cost. Nothing else gets you A-rated windows for less.
Looks and sightlines
This is where aluminium repays its premium. Because the metal is far stronger than plastic, the frames can be much slimmer while holding the same pane of glass. The result is more glass, more daylight and the crisp, minimal sightlines that suit modern extensions, large openings and bi-fold doors. uPVC frames are necessarily chunkier, which looks perfectly fine on a typical semi but can dominate a big picture window.
Worth it Aluminium for looks, especially on large or feature windows.
Lifespan
Aluminium lasts longer: around 30 to 40 years against uPVC's 20 to 25 years. Neither needs painting or real upkeep. In practice the sealed glass unit (15 to 20 years before any misting) often ages out before either frame does, so the longer aluminium life only really counts if you plan to stay put for decades. For more on how the frame and the glass age separately, see our guide to how long double glazing lasts.
Worth it Aluminium edges it on raw lifespan.
Thermal performance
Plastic conducts less heat than metal, so uPVC has a small natural thermal advantage. Modern aluminium closes nearly all of it with a polyamide thermal break running through the frame. In 2026 both materials comfortably reach the A-rated standard of 1.0 to 1.4 W/m²K that Part L of the Building Regulations requires for replacement windows, so for most homes thermal performance is effectively a draw. The glass spec matters more here than the frame.
It depends A draw in practice; uPVC has a slight edge on paper.
Maintenance
Both are genuinely fit-and-forget. uPVC needs nothing more than an occasional wipe, and powder-coated aluminium is just as undemanding, holding its colour for decades. Neither rots, neither needs painting. This is the one dimension where the two materials are simply level, and it is a big reason both have pushed timber to a niche.
Best Buy Tie. Both are essentially maintenance-free.
Nine times out of ten I fit uPVC and the customer never thinks about it again. Where I push people towards aluminium is big openings and modern extensions, where those slim frames genuinely change how the room feels. Do not pay the aluminium premium on a back bedroom nobody looks at.
Tom Bradley, FENSA-registered installer
The verdict
For most UK homes, uPVC is the Best Buy: it delivers A-rated performance at the lowest price with zero maintenance, and a 20 to 25 year life is plenty for the majority of owners. Choose aluminium where the look earns its keep, on large windows, bi-folds and contemporary extensions where slim sightlines transform the space and the longer life suits a long-term home. If you are still weighing the glazing spec itself, our comparison of double versus triple glazing covers when the extra pane is worth paying for.
Frequently asked questions
Yes. A uPVC casement window costs roughly £400 to £1,000 fitted, while the same window in aluminium costs around £550 to £1,300, about 30 to 40% more. The gap comes from the metal frame, the thermal break inside it and the more precise fabrication aluminium needs.
They do. Aluminium frames last around 30 to 40 years, against 20 to 25 years for uPVC. Both are essentially maintenance-free. Over a very long ownership the longer aluminium life can offset some of the higher upfront cost, but for most owners the difference is academic.
uPVC is naturally a slightly better insulator because plastic conducts less heat than metal. Modern aluminium frames close most of the gap with a polyamide thermal break, and both materials reach the A-rated, Part L compliant standard of 1.0 to 1.4 W/m2K when fitted with good glass.
Yes, and this is aluminium's main selling point. The metal is stronger than plastic, so the frames can be much thinner while carrying the same glass. That means more glass, more light and cleaner sightlines, which suits large windows, bi-folds and modern extensions.