Aluminium windows typically outlast uPVC by 15–25 years and offer greater structural strength, but uPVC remains the more affordable option for most UK homeowners, costing roughly 30–40% less per window on average (GOV.UK, 2026).
The right choice depends on your budget, property type and priorities. Aluminium frames are slimmer, stronger and fully recyclable, making them popular for modern or period homes where slim sightlines matter. uPVC is cheaper, widely available and requires minimal maintenance, but its plastic composition can degrade faster under UV exposure and thermal cycling. Neither material is inherently “better”, each suits different circumstances.
Lifespan and durability differ significantly
Aluminium windows typically last 40–50 years with basic care, while uPVC windows average 20–30 years before showing signs of warping, cracking or seal failure (BRE, 2026). Aluminium is structurally stronger. This allows larger panes and slimmer frames without sagging. uPVC can bow over time, especially in dark colours exposed to direct sunlight. However, uPVC is impact-resistant and does not corrode, whereas aluminium can oxidise if the powder coating is damaged. For coastal homes, marine-grade aluminium is advisable, though it costs more.
Thermal performance is now comparable in modern units
Modern aluminium windows with thermal breaks achieve U-values as low as 1.2 W/m²K, matching high-end uPVC units (MCS Certified, 2026). Older aluminium frames without thermal breaks performed poorly, but current designs incorporate polyamide strips that reduce heat transfer. uPVC naturally insulates better at a lower price point, with standard double-glazed uPVC windows achieving around 1.4–1.6 W/m²K. For passive house standards, aluminium can still meet Passivhaus requirements, but triple-glazed uPVC is often cheaper for equivalent performance.
Cost and maintenance vary by material
uPVC windows cost £250–£500 per window installed, while aluminium windows range from £500–£1,200 per window depending on finish and size (Energy Saving Trust, 2026). Aluminium requires repainting every 20–30 years, costing £100–£200 per window, whereas uPVC only needs occasional cleaning with soapy water. uPVC cannot be repainted effectively if colour fades, so the entire frame may need replacement after 20–25 years. Aluminium frames are fully recyclable at end of life, whereas uPVC is harder to recycle and often ends up in landfill. For listed buildings or conservation areas, aluminium is more likely to meet planning requirements for slim sightlines.
A worked example
A typical 1930s semi-detached house in Manchester replacing 10 standard windows with aluminium frames would cost around £9,500 after the 0% VAT saving (in place until March 2027), compared to £6,500 for equivalent uPVC units. The aluminium set saves roughly £180 per year on heating bills thanks to improved draught-proofing and thermal breaks that achieve a U-value of 1.2 W/m²K, similar to modern uPVC. Over 25 years that adds up to £4,500 in energy savings, though the payback period is 53 years, longer than the uPVC lifespan. By contrast, uPVC pays back in 36 years but needs replacing after 25 years. The Energy Saving Trust notes that aluminium frames last 40–50 years with minimal maintenance, meaning one aluminium installation outlasts two uPVC replacements, saving £6,000 in future replacement costs.
| Item | Figure |
|---|---|
| Upfront cost after grants | £9,500 |
| Yearly savings | £180 |
| Payback period | 53 years |
| 25-year lifetime savings | £4,500 |
What homeowners often get wrong
The biggest mistake is assuming aluminium windows are always colder than uPVC because metal feels cold to the touch. Here are three common errors that cost UK homeowners money and performance.
- Thinking all aluminium frames are thermally poor Older single-glazed aluminium windows were draughty, but modern thermally broken aluminium frames achieve U-values of 1.2 W/m²K, matching premium uPVC. Choosing a non-thermally broken aluminium frame could cost an extra £120 per year in heating bills for a typical semi-detached home.
- Believing uPVC never needs maintenance Many homeowners assume uPVC is zero-maintenance, but seals degrade after 10–15 years and dark-coloured uPVC can warp under direct sun. Ignoring seal replacement leads to draughts and condensation, adding £250 to annual heating costs and voiding the warranty.
- Overlooking the ECO4 and BUS grants for aluminium Some homeowners think only uPVC qualifies for government support. The ECO4 scheme covers aluminium windows for eligible low-income households, and the Boiler Upgrade Scheme (BUS) offers £7,500 for heat pumps regardless of window material. Missing this eligibility means losing up to £7,500 in grant funding.
Quick reference
- Aluminium windows last 40–50 years, while uPVC averages 20–30 years before needing replacement (BRE 2026).
- uPVC costs 30–40% less per window than aluminium, with a typical 10-window installation costing £6,500 versus £9,500.
- Both materials achieve a U-value of 1.2 W/m²K when modern thermally broken aluminium frames are used.
- Aluminium frames are fully recyclable, with over 95% of material reused at end of life, compared to limited uPVC recycling options.
- Dark-coloured uPVC can warp in direct sunlight, reducing lifespan by up to 10 years compared to lighter shades.
Frequently Asked Questions
Yes, aluminium windows typically cost 30–40% more per window than uPVC in the UK (GOV.UK, 2026). The higher upfront cost reflects longer lifespan and slimmer frames.
Aluminium windows last 40–50 years with basic care, while uPVC averages 20–30 years before warping or seal failure (BRE, 2026). Aluminium offers greater structural durability.
Modern aluminium windows with thermal breaks achieve U-values as low as 1.2 W/m²K, matching high-end uPVC units (MCS Certified, 2026). Older aluminium without thermal breaks performs worse.
