uPVC vs Aluminium Windows: Complete UK Comparison Guide

Not with modern thermal break technology. Today's aluminium windows feature a polyamide thermal barrier between the inner and outer frame faces, which prevents cold bridging and achieves U-values very close to uPVC (1.3 W/m²K vs 1.2 W/m²K). The days of cold, dripping aluminium frames are long gone. Always ensure your aluminium windows have a proper thermal break — avoid cheap imports without this feature.

Aluminium windows typically last 30-45 years compared to 20-30 years for uPVC. Aluminium does not degrade from UV exposure in the same way that uPVC can become brittle and discolour over time. The powder-coated finish on aluminium maintains its appearance for 25+ years, while uPVC foil finishes may begin to fade or peel after 15-20 years, particularly on south-facing elevations.

Yes, aluminium windows are available in traditional styles including Georgian bar designs, cottage-style configurations, and even sash window styles. However, the slim sightlines that are aluminium's main aesthetic advantage are most apparent in contemporary designs. If you want a traditional look, uPVC with woodgrain foils often provides a more convincing period appearance at a lower cost.

Not if they have a proper thermal break. Modern thermally broken aluminium windows have similar condensation resistance to uPVC. Condensation is primarily caused by high indoor humidity and poor ventilation rather than the frame material. If you experience condensation, improving ventilation through trickle vents (now mandatory under Building Regulations Part F) or extractor fans is more effective than changing window materials.

uPVC windows have improved their environmental credentials significantly. Modern uPVC is recyclable up to 10 times, and industry recycling schemes like Recovinyl aim to recycle all end-of-life uPVC windows. However, aluminium has the edge in sustainability as it is 100% infinitely recyclable with no loss of quality. uPVC production involves chlorine chemistry, which has environmental concerns, though the industry has worked to minimise its impact.

Yes, this is increasingly common. Many homeowners use aluminium windows for feature areas such as large rear glazing, extensions, or bi-fold doors, while using uPVC for standard bedroom and bathroom windows to manage costs. The key is to ensure consistent sightlines and colour matching. Some manufacturers offer uPVC and aluminium ranges in matching colours to facilitate this approach.

Both materials offer excellent security when specified correctly. Both can be manufactured to PAS 24:2022 standards and achieve Secured by Design accreditation. Aluminium's inherent strength makes the frames slightly harder to force, but the locking mechanisms and glass specification are more important security factors than the frame material. Always look for PAS 24 certification regardless of which material you choose.

In most cases, no. Window replacements are generally covered by permitted development rights, provided you use materials of similar appearance (which planning authorities interpret broadly for non-listed properties outside conservation areas). In conservation areas, changing the material or appearance of your windows may require planning permission. For listed buildings, listed building consent is always required for any window changes.

Aluminium windows can be professionally re-sprayed, though it is not a DIY job. Professional re-spraying costs approximately £100-£200 per window and involves careful preparation and application of a specialist powder-coat or wet-spray finish. uPVC windows can also be sprayed but the finish is less durable. Alternatively, aluminium window profiles can be factory-refurbished and re-coated, though this requires removal from the property.

uPVC windows typically have a shorter lead time of 2-4 weeks from order to installation, as they are manufactured in high volume. Aluminium windows usually take 4-8 weeks, as they often involve bespoke fabrication and powder coating to a specified RAL colour. Custom colours or dual-colour finishes may add an extra 1-2 weeks to the lead time.