Two premium specifications that photograph similarly and behave differently. The choice comes down to sightline, internal material and where the money should sit.
Almost every architect-led project we price reaches this fork. Both systems are properly engineered, both will outlast the mortgage, and both are a considerable step up from a volume uPVC package. They are not, however, interchangeable.
The honest summary: aluminium wins on sightline, aluclad wins on the room. Everything below is detail on that sentence.
| Thermally broken aluminium | Aluclad timber | |
|---|---|---|
| Internal face | Coated aluminium | Engineered timber, lacquered or painted |
| Sightlines | Slimmest available | Deeper frame sections |
| Whole-window U-value | Typically 1.2–1.5 W/m²K | From 1.2 double, from 0.8 triple |
| Maximum panel size | Very large — minimal-frame sliders | Large, governed by timber section and weight |
| External maintenance | Washing only | Washing only |
| Internal maintenance | None | Occasional re-finishing, indoors |
| Investment position | High | Higher |
| Best for | Minimal glazing, large openings | Rooms where the frame is seen and touched |
Aluminium is stronger per millimetre than timber, so it can hold a large pane in a much narrower frame. On a minimal-frame slider, that difference is the entire point of the product: interlocks around 25mm, glazed area above 90%, and a screen that reads as glass rather than as a door.
If the brief is a wall of glass onto a view, aluminium is the correct answer and aluclad is the wrong one. No amount of engineering makes a timber section as slender.
Stand at a window in February with your hand on the frame. Aluminium is cool and hard; timber is warm and soft. In a bedroom, a kitchen, a barn conversion with exposed structural oak, or any room where materials have been chosen carefully, that difference is not sentimental — it is the reason the specification exists.
Triple glazed, aluclad also generally out-performs aluminium thermally, because the deep timber section is a far better insulator than an aluminium profile with a polyamide break through the middle. On a low-energy or Passivhaus-adjacent project, this usually decides it.
This is more common than people expect and it is not a compromise. Aluclad windows and French doors across the principal rooms, with a minimal-frame aluminium slider across the rear opening where the sightline matters most. Colour-match the external RAL and the elevation reads as one scheme.
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Flagship guide · 5 min read
Aluclad is a solid engineered timber window wearing an aluminium coat. It is the standard specification across Scandinavia, and increasingly the answer for exposed British sites where timber is wanted but repainting is not.
Buying Guides · 3 min read
On a self build the glazing decision is made twelve to eighteen months before anyone looks through the glass. Getting aluclad right is mostly about sequencing.
Flagship guide · 7 min read
Aluminium and modern timber-look uPVC are both good materials. The right choice depends on the age and style of your house, your budget, and how the frames will be used, not on which one is fashionable.
Product Comparisons · 3 min read
The Residence Collection and aluminium sit either side of a genuine style and budget decision. This guide narrows that decision down to the details that actually matter for your house.
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