uPVC vs aluminium windows

uPVC and aluminium are the two most common frame materials for modern replacement windows, and homeowners often weigh one against the other. The honest answer is that neither is simply "better" — they suit different priorities. uPVC wins on price and insulation; aluminium wins on slim sightlines and a contemporary look. This guide compares the two fairly on the points that matter, so you can decide which is right for your home and budget.

Cost

Cost is usually the deciding factor. uPVC is significantly cheaper — a standard white casement typically costs £350 to £650 fitted, whereas an equivalent aluminium window commonly costs anywhere from 40% to 100% more. For a whole house, that difference adds up quickly. Our uPVC window prices guide sets out the uPVC ranges in full so you can see where the savings sit.

Looks and sightlines

Aluminium is strong, so its frames can be much slimmer than uPVC while still holding large panes of glass. That gives more glass, more light and a sharp, minimal look that suits contemporary extensions and rendered homes. uPVC frames are chunkier, though modern flush-casement profiles have narrowed the gap. If a crisp, industrial aesthetic is your goal, aluminium has the edge; if you want a traditional or budget-friendly finish, uPVC delivers — see the range in our window styles guide.

Insulation and energy efficiency

uPVC is naturally a good insulator, thanks to the air trapped in its multi-chamber profiles. Aluminium conducts heat, so quality aluminium windows use a "thermal break" — an insulating barrier between the inner and outer frame — to close the gap. Both materials can achieve strong Window Energy Ratings when specified well, but uPVC tends to reach a good rating at a lower cost. Our energy ratings guide explains what to look for.

Lifespan and maintenance

Both materials are low-maintenance and long-lasting. Quality uPVC windows typically last 20 to 35 years, and aluminium can last even longer thanks to its rigidity and powder-coated finish. Neither needs repainting; an occasional clean keeps both looking good. Our maintenance and lifespan guide covers how to get the most years from uPVC.

At a glance

Factor	uPVC	Aluminium
Cost	Lower	Higher
Frame slimness	Chunkier	Very slim
Insulation	Excellent	Good (with thermal break)
Lifespan	20–35 years	30+ years
Maintenance	Very low	Very low

Which should you choose?

If budget and warmth are your priorities, uPVC is hard to beat and remains the most popular choice in the UK. If you want the slimmest frames and a modern look and have the budget for it, aluminium is worth the premium. Many homeowners find uPVC gives them everything they need at a fraction of the cost.