How long do aluminium windows last?

What fails, and when

• Sealed units — 15 to 25 yearsThe edge seal degrades and the unit mists. Replaceable in the existing frame for £75–£190.
• Friction hinges — 10 to 20 yearsThe arms wear and the sash drops. £55–£110 to replace.
• Gaskets and seals — 15 to 25 yearsThey harden and stop compressing. Renewable.
• Handles and locks — 10 to 20 yearsMechanical wear. Cheap to replace.
• The frame — 30 to 50 yearsAnd it will still be structurally sound when everything above has been replaced twice.

Coastal exposure changes the answer

Within a mile or two of salt water, a standard powder coat will chalk, pit and eventually fail far sooner than 25 years. Specify Qualicoat Seaside grade, which uses a heavier pre-treatment specifically for marine environments — and rinse the frames with fresh water a few times a year. On an exposed seafront elevation, that maintenance genuinely doubles the life of the finish.

The comparison that matters

uPVC: 20–25 years, and the colour cannot be restored once the foil lifts or the white yellows. Timber: indefinite if maintained, a decade if not. Aluminium: 30–50 years with essentially no maintenance.

Over a 40-year horizon you will normally buy uPVC windows twice and aluminium windows once. That is the real cost comparison, and it is the one that almost nobody makes at the point of sale.