Aluminium vs uPVC Windows Cost Difference Calculator

How this calculator works

This calculator compares typical UK supplied-and-fitted price ranges for the two options, drawn from published 2026 industry cost guides. Your inputs scale those base ranges: the calculator multiplies the per-unit range for each option by the number of units and by adjustment factors for the choices you make below, then shows both totals side by side along with the estimated difference between them. Because real quotes vary, everything is expressed as a range from a realistic low to a realistic high rather than a single figure.

Aluminium windows typically cost 1.5 to 2 times as much as uPVC, so in 2026 a standard aluminium casement runs roughly to fitted against to for uPVC. Across a full house of 10 to 12 windows that is commonly a difference of or more, which is why the choice deserves a proper look at what each material offers.

Number of windows

Enter how many windows you are comparing prices for. The difference between the two options scales with the number of windows, so a premium that looks small per window can become significant across a whole house.

Window size

Size is one of the biggest cost drivers for any glazed unit. A larger opening needs more frame material and a bigger, heavier sealed glass unit, and it usually takes longer to fit. The calculator uses three broad size bands based on common UK window dimensions: choosing the small band reduces the typical range by around 20 percent, while the large band increases it by around 40 percent. If your windows vary in size, run the calculator once per size band and add the results together.

Specification level

Two windows that look similar from the street can sit at very different price points. Budget products use simpler profiles, standard hardware and basic glass. Mid-range covers the typical A-rated units most UK installers quote by default. Premium covers high-end systems with upgraded security hardware, better thermal performance, special finishes or designer profiles, and typically adds around 30 percent to the price.

Where you live

Labour rates are not uniform across the UK. Published cost guides consistently show installation prices in London and the South East running roughly 20 to 30 percent above the national average, driven by higher labour costs, travel, parking and congestion charges. The calculator applies an uplift of around 20 percent if you select London and the South East. Product prices themselves are broadly similar nationwide, so the difference mostly reflects fitting costs.

What else affects the price

uPVC wins on price and thermal performance per pound, and quality systems now last 20 to 35 years with minimal care. Aluminium justifies its premium through slimmer sightlines that allow more glass, powder coated finishes in any colour with 25 year guarantees, greater strength for large openings, and lifespans of 45 to 60 years, roughly double uPVC. Aluminium frames must be thermally broken to match uPVC insulation. A common middle path is mixing materials: aluminium on large feature openings where the slim frames earn their keep, and uPVC elsewhere.

Planning permission, building regulations and certification

Like-for-like window replacement on most houses does not need planning permission, but listed buildings always require consent and conservation areas often restrict materials and styles on visible elevations, so check with your local planning authority if either applies. Building regulations apply to every replacement window in a dwelling, setting minimum energy performance and safety glazing standards. Installers registered with a competent person scheme, such as FENSA or Certass, can self-certify compliance and issue a certificate after completion; otherwise you must arrange building control sign-off separately. Keep the certificate safe, as buyers’ solicitors routinely ask for it when you sell.