5 min read
Both are good products. The right choice comes down to budget, the look you want and the size of the openings — not to which one a salesperson makes more margin on.
Cost
uPVC is the cheaper option, typically 40–60% less than the aluminium equivalent for the same opening. On a whole house that's often the difference between £5,000 and £8,000.
Looks and sightlines
Aluminium is stronger, so the frames can be much slimmer — more glass, less frame, and a sharper modern look. It also holds a powder-coated finish beautifully in colours like anthracite grey and matt black.
uPVC has improved enormously. Flush casement uPVC in heritage colours looks close to painted timber and suits older stone properties around Rochdale, Whitworth and Saddleworth very well.
Thermal performance
uPVC is naturally a poor conductor of heat, so it insulates well without help. Aluminium conducts heat, so quality aluminium windows use a polyamide thermal break between the inner and outer frame. With a decent thermal break and modern glass, both comfortably meet current requirements — a cheap aluminium window without a proper break does not.
Strength and large openings
For wide spans — big picture windows, large sliding doors, bi-folds — aluminium wins. It stays rigid where uPVC needs bulky reinforcement or additional mullions that spoil the view. This is why we only fit bi-folds in aluminium.
Lifespan and maintenance
Both are essentially maintenance-free beyond cleaning and occasional hinge lubrication. Good uPVC lasts 20–30 years; quality powder-coated aluminium often 30–40, and it won't discolour in strong sun the way cheap white uPVC can.
Our usual recommendation
uPVC for most whole-house replacements where budget matters. Aluminium for large openings, contemporary extensions, bi-folds and sliders, and commercial work. Plenty of our customers mix the two — uPVC on the bedrooms, aluminium across the back of the extension.
FAQs
Is aluminium colder than uPVC?
Not with a proper polyamide thermal break and modern glazing. Always check the thermal break exists — that's where cheap aluminium cuts corners.
Can I have grey outside and white inside?
Yes, dual-colour frames are available in both materials.
Which adds more value to a house?
Either, if fitted well. Aluminium tends to suit contemporary and high-value properties; heritage uPVC suits period homes.