Aluminium Windows Installation and Replacement Cost Calculator

How this calculator works

This calculator estimates a realistic price range rather than a single figure, because real-world quotes genuinely vary that much. It starts from typical UK supplied-and-fitted price ranges drawn from published 2026 industry cost guides, then multiplies them by the number of units you enter and by adjustment factors for each choice you make below. The result is a low-to-high band that a fair quote is likely to fall within, not a promise of the exact price you will pay.

Aluminium casement windows typically cost around to supplied and fitted in 2026, roughly 1.5 to 2 times the price of equivalent uPVC. In return you get slimmer frames, larger possible glass areas, powder coated finishes with 25-year guarantees on quality systems, and expected lifespans of 45 to 60 years, roughly double that of uPVC.

Number of aluminium windows

Enter how many aluminium windows you want installed or replaced. Aluminium suits large glazed openings particularly well because its strength allows bigger panes with slimmer frames than uPVC can manage.

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.

Finish

Aluminium frames are powder coated and can be finished in virtually any RAL colour. Standard whites, greys and blacks are usually stocked and cheapest, while special colours and dual-colour frames, with a different finish inside and out, typically add 10 to 20 percent and can extend lead times.

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

The key technical point with aluminium is the thermal break, the insulating barrier within the frame that stops the metal conducting heat out of the house. Quality thermally broken systems comfortably meet current building regulations; older or budget systems without effective breaks perform far worse. Heritage steel-look aluminium, designed to mimic slim Crittall-style frames at a lower cost than genuine steel, sits at the top of the aluminium price range. As with all windows, larger sizes, more openers and difficult access all increase quotes.

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.