uPVC vs Aluminium Windows: Which Is Right for You?

uPVC windows use multi-chamber plastic profiles that provide excellent thermal insulation at an accessible price point. Aluminium windows use thermally broken metal frames that offer slimmer sightlines and a more contemporary aesthetic but at a higher cost. Both are low-maintenance, durable and available in a wide range of colours. The choice between them depends on your priorities: budget, aesthetics, thermal performance and property style.

Modern uPVC windows achieve A-rated energy performance as standard, with multi-chamber profiles and warm-edge spacer bars. Aluminium windows have improved dramatically — thermally broken aluminium profiles now achieve comparable U-values to uPVC. However, uPVC still has a slight edge in pure thermal performance because plastic is a natural insulator, whereas aluminium conducts heat and relies on a thermal break to interrupt the heat path.

This is where aluminium excels. Aluminium frames can be significantly slimmer than uPVC — typically 40-60mm compared to 70-100mm. This means more glass, more light and a sleeker appearance. For contemporary properties, extensions and large-format openings (bi-folds, sliding doors), aluminium's slim profiles are a clear aesthetic advantage. For traditional properties, uPVC's chamfered or sculptured profiles can faithfully replicate the look of original timber windows.

Both materials are low-maintenance and long-lasting. uPVC won't rot, rust or need painting, and a quality uPVC window should last 25-30 years. Aluminium is even more durable — it won't warp, crack or degrade, and powder-coated finishes carry 25-year guarantees against fading and peeling. Both require nothing more than occasional cleaning with soapy water.

uPVC is typically 20-40% cheaper than aluminium for equivalent window sizes. For a full house of windows, this difference can be significant. However, aluminium's longer lifespan and premium aesthetics can justify the higher initial cost, particularly for higher-value properties where the investment adds to resale value.

Choose uPVC if: you want the best value for money, you're replacing windows in a traditional property, or thermal performance is your top priority. Choose aluminium if: you want the slimmest frames and most glass, you're building a contemporary extension, or you want the longest possible lifespan. Many homeowners use a combination — uPVC for standard windows and aluminium for feature openings like bi-folds and sliding doors.