PVC vs aluminium windows and doors: the honest comparison, point by point

PVC or aluminium? It’s the question we’re asked most. Short answer: it depends. Useful answer: it depends on these five variables set out below.

Thermal insulation

Winner: PVC, by a narrow margin.

PVC is naturally insulating. Aluminium is a conductor: to make it thermally comparable it needs a thermal break, a strip of insulating polyamide inserted into the profile — we explain exactly how this works in detail here. With a modern thermal break, premium aluminium reaches Uw 1.0-1.2 W/m²K. Top-of-range PVC gets down to 0.9. For equivalent glazing and quality, PVC always insulates a touch better than aluminium, but the gap has narrowed considerably over the last 10 years.

Acoustic insulation

A draw. Acoustic insulation is mainly a function of the glazing (asymmetry, lamination, thickness) and the perimeter gaskets. Both materials, with multiple gaskets and 44.2/44.1 laminated glass, reach Rw 42-45 dB.

Durability

Winner: aluminium.

Aluminium is practically everlasting. It doesn’t warp, doesn’t rot, and Qualicoat powder coating withstands salt spray, pollution and UV for decades. Quality PVC lasts 40-50 years with no problems, but is more sensitive to extreme temperatures (very sunny areas with direct exposure) — less of an issue today thanks to UV additives.

Design and frames

Clear winner: aluminium.

Aluminium allows frames as slim as 70-80 mm, with a visible face of as little as 90 mm. PVC has bulkier sections (130-150 mm of visible frame plus sash). For large glazed walls, wide sliding doors and contemporary minimalist design, aluminium is the choice.

Price

Winner: PVC.

For equivalent performance, PVC costs 20-30% less than aluminium. Real-world example: a 120×140 PVC Salamander 76 window with double glazing costs around €500-600 installed (market reference); the same window in LMT 70 thermal-break aluminium, €700-800.

Colour customisation

Winner: aluminium.

Qualicoat powder coating in any RAL shade, even bi-colour (one colour outside, another inside) at no extra cost. Anodised, stainless-steel and Corten-style finishes are available. PVC has more limited availability — white, a few greys, woodgrain finishes via films; the film can deteriorate over time if exposed directly to strong sun (although modern films are much improved).

Maintenance

Winner: both PVC and aluminium, over timber.

Neither PVC nor aluminium requires painting or treatment. Periodic cleaning with water and a neutral detergent is all that’s needed.

Sustainability

A draw.

Aluminium is 100% infinitely recyclable, and most of the aluminium in circulation is already recycled. PVC is recyclable too, although in practice PVC recycling is more complex. Both materials last decades and so have their environmental impact amortised over a long timeframe.

When to choose PVC

• Modest budget with high performance
• Standard replacement in a flat or house with normal-sized windows
• Cold climate zones (maximum insulation for the price)
• When frame design isn’t a critical factor

When to choose aluminium

• Large glazed walls, very wide French doors, wide sliding doors
• Contemporary architectural design, slim frames
• Direct marine exposure with strong salt spray
• When a lifespan beyond 50 years is the priority (e.g. restored period properties, high-value buildings)
• Significant colour customisation (bi-colour, specific RAL shades)

The hybrid solution: timber-aluminium

It’s worth considering a third option: timber-aluminium windows combine timber on the inside (warm aesthetics, insulation) with aluminium on the outside (weather resistance, zero external maintenance). Higher cost (30-50% more than top-tier PVC), but for high-value residential projects it’s the solution that wins on every front.

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For your specific case — dimensions, exposure, budget, climate zone — the fastest way to find the right choice is a free quote. Request one here and within 24 hours you’ll have a detailed quote comparing the alternatives.