Cost & Budget Guides · 5 min read
How Much Do Aluminium Windows Cost?
Aluminium windows typically cost £1,400–£2,600 per window supplied and installed. Here is what moves you up or down that range.
Why Are Aluminium Windows So Expensive?
Aluminium costs more because more of the cost sits in engineering than in extrusion: thermal breaks, tolerances, coating, hardware and glass that a slimmer frame forces you to get right.
4 min read
Written by Windows in the Lakes · A trading name of Home Glazing Ltd · Last reviewed 21 September 2026
Short answer
In short: an aluminium window is more expensive than a mass-market uPVC one because the frame is a precision-engineered composite of two aluminium shells bonded to an insulating core, powder coated to an architectural standard, fitted with heavier hardware and carrying larger panes of glass. Very little of the difference is the metal itself.
That also means the word 'aluminium' guarantees nothing. There is a wide spread of quality within the material, and a cheap aluminium window can perform worse than a good uPVC one. The useful question is not whether aluminium is expensive but which parts of the price are buying you something.
Where the money actually goes
Break an aluminium window into its parts and the cost lands in predictable places. Understanding the split makes quotations far easier to compare, because two suppliers can quote the same material and be selling quite different objects.
| Element | Why it costs | What a lower price usually means |
|---|---|---|
| Frame system | Multi-chamber extrusions, polyamide thermal break, tested as a system | A thinner, simpler profile with a smaller thermal break |
| Glass | Larger panes, coatings, warm-edge spacers, argon or triple units | Standard double glazing with a basic coating |
| Powder coating | Architectural-grade pretreatment and coating, often marine specification inland too | Standard coating, fewer colours, shorter coating warranty |
| Hardware | Heavier hinges and locking to carry bigger sashes | Lighter gear rated for smaller openings |
| Manufacture | Tight tolerances so slim sightlines stay square | Wider tolerances, more visible packing and adjustment |
| Installation | Survey, removal, fixing, sealing and making good | Fitting only, with making good excluded |
The thermal break is most of the engineering
Aluminium conducts heat well, which is exactly what you do not want in a window frame. A modern system solves this by making the frame in two halves — an outer shell and an inner shell — separated by polyamide strips that carry the structural load while interrupting the heat path. The depth and shape of that break, and how the chambers around it are arranged, is where the performance difference between systems lives.
Why the same window costs more in a bigger opening
Cost does not rise smoothly with area. Every system has a point where the sash becomes heavy enough to need a different hinge set, the glass needs to be laminated, the unit needs two people or a lifting frame to install, and the frame needs reinforcing. Crossing that threshold can cost more than the extra square metre.
- Large opening sashes need heavier gear and sometimes restrictors, which is a hardware cost rather than a glass cost.
- Glass above certain sizes changes from toughened to laminated, and larger units carry a handling premium.
- Anything that cannot be carried by hand needs access equipment, which appears in the installation line rather than the product line.
- Fixed glazing is almost always the cheapest way to buy glass area — a wall of opening sashes is an expensive way to get daylight.
When the aluminium premium is not worth paying
There are houses where aluminium earns its price immediately: large openings, slim sightlines against a lot of glass, contemporary extensions, exposed sites where a durable finish matters. There are also houses where it does not.
- Small cottage openings, where the frame is barely visible and a well-made flush timber-look alternative reads better and costs less.
- Period elevations where a heritage profile matters more than a slim one.
- Phased projects where the budget is better spent on getting the whole house done in one consistent specification.
We will say so when that is the case. Recommending a more expensive material into the wrong building is how projects end up looking wrong and costing more than they needed to.
Terms used in this guide
- Thermal break
- An insulating barrier inside an aluminium frame separating the inner and outer faces of metal, so heat is not conducted straight through the frame.
- Polyester powder coat
- The factory-applied paint finish used on aluminium frames, baked on for durability and specified by a RAL colour and gloss level.
- U-value
- The rate at which heat passes through a building element, in W/m²K. A lower number means less heat loss. Window U-values may be quoted for the glass alone or for the whole window; the whole-window figure is the comparable one.
Sources and further reading
Regulatory and technical points in this guide should be checked against the current published guidance below, and against the specific circumstances of your property.
Guidance last reviewed 21 September 2026 by Windows in the Lakes
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