Comparison

Aluminium vs timber windows and doors

By Paul Fradley, Founder and Technical Lead · Updated June 2026

Aluminium wins where the brief is slim sightlines, large spans and a finish that never needs repainting; timber wins on conservation and heritage work where a natural material and traditional detailing are required. Both reach strong thermal and weather performance when specified correctly. We fabricate aluminium for the trade and quote the right system per opening, so this page sets out where each material wins on a like-for-like basis. Tell us the opening and target spec and we will quote the aluminium route.

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Aluminium vs timber windows and doors, aluminium by VitrineAlu

No repaintingPowder-coated aluminium holds colour with routine cleaning only; timber needs a recoat cycle

Slimmer sightlinesAluminium frames carry more glass per opening; timber sections sit heavier for the same span

Larger spansAluminium sliding sashes to 2.2x2.87m at 420kg per panel where specified

Which is more thermally efficient, aluminium or timber?

Both materials reach low whole-unit U-values when specified for it, and the achievable figures now overlap. Timber is naturally low-conductivity, so older comparisons favoured it; modern aluminium uses polyamide thermal breaks to close that gap.

On our aluminium systems, casement reaches Uw from 0.85, bifold from 0.9, sliding from 1.0 and the high-insulation tilt-turn route from 0.66, all where specified and with the glazing spec to match. Glazing runs 22 to 58mm depending on system. Timber can match these figures with the right build-up. Confirm the whole-unit Uw against your target at quote, because frame mix, glass and opening size all move it. See our U-values guide for the detail.

Aluminium casement: Uw from 0.85 where specified
Aluminium bifold: Uw from 0.9 where specified
Aluminium tilt-turn: from 0.66 on the high-insulation route
Timber: comparable figures achievable with the right glazing build-up
Whole-unit Uw confirmed at quote for both materials

How does maintenance compare over the life of the unit?

Aluminium needs no repainting. A powder-coated frame is cleaned with mild detergent and the moving parts are lubricated periodically; that is the routine. Timber needs an ongoing recoat cycle to keep the seal and the finish, and exposed elevations need it more often.

For the trade this is the clearest practical split. Aluminium removes a recurring maintenance task and the callbacks that come with it. Timber keeps it, in exchange for the look and the ability to refinish or change colour on site later. Aluminium finishes cover full RAL, dual-colour, anodised-style and matt, satin, gloss or textured architectural powder coat.

Aluminium: clean and lubricate; no repainting
Timber: periodic recoat to maintain seal and finish
Aluminium colour is factory-applied; timber can be refinished on site
Exposed elevations increase the timber recoat frequency

Which material lasts longer?

Both are long-life materials when maintained to their respective regimes. Aluminium does not rot, warp or corrode in normal use and the powder-coat finish holds colour for the long term with cleaning only. Timber lasts equally well when the recoat cycle is kept up, but it depends on that upkeep to stay sealed against moisture.

The difference is dependence, not headline lifespan. Aluminium performance is largely independent of maintenance; timber performance is tied to it.

Which gives slimmer sightlines and more glass?

Aluminium carries more glass per opening because its strength lets frame sections stay slim. Timber needs a deeper section for the same structural job, so the visible frame sits heavier and the glass area is smaller for a given hole.

Where the brief is maximum daylight or a minimal modern look, aluminium wins on sightline. Where the brief is a traditional putty-line or heritage profile, timber suits the aesthetic, and our heritage aluminium route covers projects that want the slim look with the heritage detailing. Browse the range on products.

Aluminium: slim sections, more glass per opening
Timber: deeper sections for the same span
Heritage aluminium to 1.8x1.8m at 100kg, from 1.0, for slim traditional looks
Curtain walling units to 1.5x3.6m at 350kg, 66mm sightline, Ucw from 0.6

What spans and weights can each carry?

Aluminium handles large, heavy openings without the section growing unworkable. Our verified maximums where specified: bifold leaves to 1.2x3.0m at 130kg and up to 14 leaves; sliding sashes to 2.2x2.87m at 420kg with a 35mm interlock; casement to 1.3x2.4m at 160kg; entrance doors to 1.2x2.4m.

Timber can be built large too, but at scale the section depth and weight climb and the practicalities tighten. For wide spans and big moving panels, aluminium is the more straightforward route. Confirm leaf sizes and configurations at quote.

Bifold: to 1.2x3.0m at 130kg, up to 14 leaves
Sliding: to 2.2x2.87m at 420kg, 35mm interlock
Casement: to 1.3x2.4m at 160kg
Entrance: to 1.2x2.4m, from 0.77

How does weather, security and acoustic performance compare?

Aluminium tests to the top weather classes where specified: air permeability Class 4 (EN 12207), watertightness to Class 9A (EN 12208) and wind resistance to Class C5 (EN 12210). Acoustic reaches Rw 46 dB and security meets PAS 24, including PAS 24:2025. Timber can be specified to high weather and security standards as well; the classes depend on the system and the build.

For exposed elevations and security-led briefs, ask for the target class up front and we will confirm what the specified aluminium system meets. See our security and energy efficiency pages for the detail, and the acoustic guide for noise-led specs.

Air permeability Class 4 (EN 12207) where specified
Watertightness to Class 9A (EN 12208)
Wind resistance to Class C5 (EN 12210)
Acoustic to Rw 46 dB; security to PAS 24 incl PAS 24:2025

What about cost and sustainability?

On cost, neither material is automatically cheaper across the board; it turns on system, size, glazing and finish. Timber carries a recurring recoat cost that aluminium does not, so whole-life cost can favour aluminium even where first cost is close. Price both against the actual spec rather than the material label.

On sustainability, aluminium is highly recyclable and recycles repeatedly without losing properties, which supports end-of-life recovery. Timber is a renewable material when responsibly sourced. Both have a credible sustainability case; the right call depends on the project's priorities and the spec in front of you. Send the opening and we will quote the aluminium system to match.

Common questions

Is aluminium better than timber for windows and doors?

Neither is better outright. Aluminium suits slim sightlines, large spans and a no-repainting finish; timber suits conservation and heritage work where a natural material and traditional detailing matter. Both reach strong thermal and weather performance when specified for it. Choose by the brief: maximum glass and low maintenance point to aluminium, conservation aesthetics point to timber.

Does aluminium need repainting like timber?

No. Powder-coated aluminium needs cleaning with mild detergent and periodic lubrication of moving parts only; the colour holds long term without repainting. Timber needs an ongoing recoat cycle to keep the seal and finish, more often on exposed elevations. This is the clearest practical difference between the two for the trade.

Can aluminium match timber on thermal performance?

Yes, where specified. Modern aluminium uses polyamide thermal breaks, so achievable U-values now overlap with timber. Our aluminium reaches casement Uw from 0.85, bifold from 0.9 and the high-insulation tilt-turn route from 0.66. Confirm the whole-unit Uw against your target at quote, as glazing, frame mix and opening size all affect it.

Which gives slimmer frames and more glass?

Aluminium. Its strength lets frame sections stay slim, so it carries more glass per opening than timber, which needs deeper sections for the same span. For maximum daylight or a minimal modern look, aluminium wins on sightline. For a traditional profile our heritage aluminium route delivers the slim look with heritage detailing, to 1.8x1.8m at 100kg, from 1.0.

When should I choose timber over aluminium?

Choose timber for conservation areas and heritage properties where a natural material and traditional detailing are required or preferred, and where the client accepts the recoat maintenance cycle. Choose aluminium for slim sightlines, large or heavy spans, top weather and security classes, and a finish that needs no repainting. Tell us the opening and target spec and we will quote the right aluminium system, or route a homeowner to a vetted installer via find an installer.

Completed North West new build with VitrineAlu anthracite aluminium bifold doors, windows and dormers — The frame disappears, the view does the talking.

Proof, not promises

Specified and made by people who have fitted it

Paul Fradley, Founder and Technical Lead, has worked almost every role in windows and doors across more than twenty years: surveyed, fabricated on the floor, fitted on site, then ran the technical and operations side. He leads the spec on every project, so what we quote is what we fabricate.

4.5 / 5 from 20 Google reviews. Council for Aluminium in Building member. Tested to BS EN 14351-1 and BS EN 13830 where specified.

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