UPVC vs Aluminium Windows: Which Is Best for Your London Home?
It's one of the first decisions every homeowner faces when replacing windows, and it's genuinely not obvious which is "better" — because UPVC and aluminium excel in different areas. Choosing the wrong one for your property type, budget, or priorities can mean overpaying for features you don't need, or under-investing in a window that won't perform the way you expect.
This guide compares UPVC and aluminium windows directly across the factors that actually matter — cost, durability, appearance, thermal performance, and suitability for different London property types — so you can make a confident decision before requesting quotes.
Quick Comparison: UPVC vs Aluminium Windows
| Factor | UPVC | Aluminium |
|---|---|---|
| Upfront cost | Lower | Higher (typically 30–60% more) |
| Lifespan | 20–25 years | 30–40+ years |
| Frame thickness | Bulkier | Slim sightlines |
| Maintenance | Very low | Very low |
| Thermal performance | Excellent | Very good (with thermal break) |
| Best suited to | Traditional homes, budget-focused projects | Period conversions, contemporary extensions, large glazing |
| Colour/finish options | Wide range, foiled finishes available | Wide range, powder-coated, doesn't fade as easily |
| Recyclability | Limited | Fully recyclable |
UPVC Windows: The Case For
UPVC remains the most popular window material across UK homes, and for good reason.
Strong thermal efficiency at a lower price point.
Modern UPVC windows achieve A-rated (and often A++) energy performance, meaning the material itself isn't a compromise on efficiency — it's simply more cost-effective to manufacture and install than aluminium.
Very low maintenance.
UPVC doesn't rust, rot, or need repainting. An occasional wipe-down is typically all that's required to keep frames looking new.
Wide style and colour range.
Foiled UPVC finishes now convincingly replicate wood grain, anthracite grey, and other popular contemporary colours, closing much of the aesthetic gap with aluminium and timber.
Where it falls short.
UPVC frames are inherently bulkier than aluminium, which can be noticeable on larger openings or where slim, minimal sightlines are a priority — such as bi-fold doors or floor-to-ceiling glazing.
Aluminium Windows: The Case For
Aluminium has become the material of choice for a growing share of London homeowners, particularly on extensions, period conversions, and contemporary renovations.
Slim, modern sightlines.
Aluminium's strength allows for much thinner frames than UPVC, which means more glass and less frame — a look increasingly favoured in London property renovations and rear extensions.
Exceptional durability.
Aluminium frames typically last 30–40+ years without warping, and hold their colour and finish significantly better over time than UPVC, particularly in direct sunlight.
Better suited to large or bespoke openings.
For bi-fold doors, panoramic sliding doors, and oversized windows, aluminium's structural strength makes it the more practical — often the only realistic — choice.
Fully recyclable.
For homeowners prioritising sustainability, aluminium has a notably better environmental profile at end-of-life than UPVC.
Where it falls short.
The higher upfront cost is the main barrier — aluminium windows typically cost 30–60% more than equivalent UPVC, which can meaningfully affect budgets on whole-house replacement projects.
Which One Suits Your Property Type?
Victorian & Edwardian terraces (common across Croydon and much of London):
UPVC sash-style windows offer a cost-effective way to replicate traditional aesthetics with modern performance. Aluminium is also increasingly used here for a more contemporary contrast, particularly on rear extensions.
Period conversions and flats:
Aluminium's slim frames tend to suit the proportions of period properties being modernised, especially where large glazing is part of the renovation.
New-build extensions and garden rooms:
Aluminium is the dominant choice for bi-fold doors, sliding doors, and floor-to-ceiling glazing, due to its strength-to-frame-width ratio.
Budget-conscious full-house replacements:
UPVC remains the most practical option for homeowners replacing 8+ windows across a property, offering strong performance without the higher aluminium price tag across every opening.
Mixed approach:
Many London homeowners choose UPVC for standard windows throughout the home and aluminium specifically for a rear extension, bi-fold door, or feature window — balancing budget with design impact where it matters most.
Energy Efficiency: Is There a Real Difference?
Both materials can achieve strong energy ratings when paired with quality double or triple glazing. The frame material itself has a smaller impact on overall thermal performance than the glazing unit and installation quality. In practice:
UPVC's inherent insulating properties give it a slight natural advantage in raw thermal performance.
Aluminium requires a "thermal break" (an insulating barrier within the frame) to match UPVC's efficiency — standard on all quality aluminium windows fitted today, so the practical difference for homeowners is minimal.
The bigger factor for your energy bills is glazing quality and correct installation — which is why working with an experienced, certified installer matters more than the material choice alone.
Making the Final Decision
If you're still unsure, these three questions typically settle it:
1. Is budget the primary constraint?
→ UPVC
2. Are you doing a rear extension, bi-fold doors, or want the slimmest possible sightlines?
→ Aluminium
3. Is your property a period conversion or contemporary renovation where appearance is a top priority?
→ Aluminium, or a mixed approach
FAQs
Is aluminium worth the extra cost over UPVC?
For larger glazing, bi-fold doors, and properties where slim sightlines matter, yes — the durability and design benefits typically justify the price difference. For standard-sized windows across a full-house replacement, UPVC often delivers better value.
Do aluminium windows need more maintenance than UPVC?
No — both are low maintenance. Aluminium tends to hold its colour and finish slightly better over the long term, particularly in direct sun exposure.
Can I mix UPVC and aluminium windows in the same property?
Yes, this is a common and practical approach — many homeowners use UPVC for standard windows and aluminium for feature areas like extensions or bi-fold doors.
Which is better for noise reduction — UPVC or aluminium?
Both perform similarly when paired with quality double or triple glazing; noise reduction depends more on the glazing specification than the frame material.
How do I know which option is right for my specific property?
A free home visit and quote is the best way to get a tailored recommendation based on your property type, budget, and priorities.
Not Sure Which Option Is Right for You?
We supply and fit both premium UPVC and aluminium windows across London and Croydon, and we're happy to talk through the right choice for your property — no pressure, just honest advice.
Call: 07804 623910 | Email: info@energystarhomes.co.uk | WhatsApp Us — Free consultations and quotes, 7 days a week.
