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uPVC vs Aluminium Windows: The 2025 Guide
uPVC vs Aluminium Windows: The 2025 Guide
uPVC vs. Aluminium Windows The 2025 Guide- Choosing the right material for your new windows is one of the biggest decisions you’ll make for your home. It impacts everything from your heating bills and security to your home’s kerb appeal. The two most popular and debated choices in the UK are uPVC (unplasticised polyvinyl chloride) and aluminium.
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But which one is truly better?
The simple answer is: it depends entirely on your priorities. Are you driven by budget? Are you looking for the slimmest possible frames? Is maximum thermal efficiency your number one goal?
As an award-winning installer trading in Hampshire since 1983, we at KJM have fitted thousands of windows of both types. We’re not just a “Which? Trusted Trader“—we were named their Trader of the Month in February 2024. Our entire approach is built on honest, expert-led advice, which is why we’ve created this guide to help you make the right choice.
uPVC vs. Aluminium: At a Glance
| Feature | uPVC Windows | Aluminium Windows |
|---|---|---|
| Cost | Lower. Generally the more budget-friendly option. | Higher. A premium product, often 30-50% more. |
| Thermal Efficiency | Excellent. Modern multi-chambered frames are fantastic insulators. | Excellent. Modern frames have a “thermal break” to stop heat transfer. |
| Aesthetics | Versatile. Available in many colours & woodgrains. Frames are typically wider. | Sleek & Modern. Frames are much slimmer, allowing for larger glass panes. |
| Durability & Lifespan | Very Good. 20-30 years. White frames may discolour over decades. | Exceptional. 40-50+ years. Extremely robust and weather-resistant. |
| Maintenance | Very Low. Wipe-clean finish. No painting required. | Very Low. Wipe-clean, powder-coated finish. No rusting or flaking. |
| Security | Excellent. With multi-point locking and internal beading. | Excellent. Extremely strong material. Paired with multi-point locking. |
The Detailed Breakdown: uPVC vs. Aluminium
Let’s dive deeper into each of these points to help you understand the real-world trade-offs.
1. Cost & Overall Value
- uPVC: For most homeowners, uPVC is the clear winner on price. The material is cheaper to manufacture, and the production process is incredibly efficient. This makes it a fantastic, high-performance choice for those on a stricter budget, or for larger projects where the cost difference really adds up.
- Aluminium: Aluminium is a premium product and its price reflects that. The raw materials and manufacturing process are more complex. However, its exceptional lifespan of 50+ years means that its long-term value is outstanding. You may never need to replace them again.
Winner: uPVC for upfront cost, Aluminium for long-term investment value.
2. Thermal Efficiency & Warmth
This is the most common question we get, and the answer has changed a lot in the last decade.
- uPVC: uPVC is a natural insulator. It doesn’t conduct cold or heat well. When combined with a modern, multi-chambered internal frame design, uPVC windows provide fantastic thermal performance and can easily achieve A+ energy ratings, helping to keep your home warm and your heating bills low.
- Aluminium: In the past, aluminium was a poor insulator (think old, cold 1980s window frames!). This is no longer true. Modern aluminium windows are now built with a “thermal break” – a strip of non-conductive material within the frame that stops the cold from the outside from transferring to the inside. This innovation means they now compete with uPVC for thermal performance, also achieving A+ ratings.
Winner: It’s a tie. Both modern uPVC and thermally-broken aluminium offer excellent energy efficiency. Don’t let anyone tell you otherwise.
3. Aesthetics & Design
This is where you’ll see the most obvious difference.
- uPVC: Frames are naturally thicker to provide the necessary structural strength. While this is perfect for many properties, it does mean you have less visible glass area. However, the design options are huge, with dozens of solid colours and realistic woodgrain finishes (like Irish Oak or Anthrate Grey) available.
- Aluminium: This is aluminium’s biggest advantage. The material is incredibly strong, so the frames can be significantly slimmer (we call them ‘slim sightlines’). This means you get a larger glass-to-frame ratio, which lets in more natural light and provides a sleek, modern, and high-end look. It’s the top choice for contemporary homes, extensions, and properties with a great view. They can also be powder-coated in any RAL colour you can imagine.
Winner: Aluminium, for its slim frames, modern look, and vast colour choice.
4. Durability & Lifespan
- uPVC: A high-quality uPVC window will last 20-30 years. The material is durable, won’t rot, and is weather-resistant. The only potential issue is that white uPVC can, after several decades, begin to fade or yellow slightly from UV exposure.
- Aluminium: Aluminium is in another class. It’s exceptionally strong, and the powder-coated finish protects it from the elements. It will not warp, flex, rot, or rust. It’s not uncommon for an aluminium window to last 40-50 years or more, looking as good as the day it was installed.
Winner: Aluminium, by a clear margin.
5. Maintenance
- uPVC: Requires almost no maintenance. A simple wipe-down with soap and water a couple of times a year is all that’s needed to keep the frames looking new.
- Aluminium: Exactly the same. The powder-coated finish is tough and easy to clean. A quick wash is all it takes.
Winner: It’s a tie. Both are fantastic low-maintenance options.
So, Which One is Right for My Home?
Still undecided? Here’s the KJM verdict to help you choose.
✅ You should choose uPVC if:
- Budget is your primary consideration.
- You want the best possible thermal efficiency for your money.
- You have a more traditional property where a classic white or woodgrain finish is a perfect match.
- You are looking for a reliable, low-maintenance, and proven all-rounder.
✅ You should choose Aluminium if:
- Aesthetics and a modern look are your top priority.
- You want the slimmest possible frames and the largest possible glass area.
- You are looking for a specific or non-standard colour to match your home.
- You are specifying windows for a “forever home” and want the longest possible lifespan and durability.
Why Choose KJM for Your New Windows?
The product is only half the story. The quality of the installation and the after-sales service is what defines your experience. This is where KJM stands apart.
🏅 An Award-Winning Team You Can Trust
We believe in accountability. Our commitment to quality isn’t just a promise, it’s been repeatedly recognised by the industry and, most importantly, our customers.
- Which? Trusted Trader of the Month (Feb 2024)
- 6-Time Winner of the Network VEKA Award for Best Installer (South)
- Test Valley Business Award Winner for Customer Service
- Inspire Business Award Winner for Customer Service
- G-Awards “Installer of the Year” Finalist (multiple times)
🤝 Our “No Pressure Promise”
We are fundamentally different from other window companies.
“Superb from start to finish… NO hard sell, or made up sales ‘must phone my boss’ talks. Really good from start to finish.” – KJM Customer Review
Our sales team is salaried, not commission-based. We will never pressure you to “sign on the night.” We provide a detailed, itemised quote for you to consider in your own time. Our job is to give you the best advice, not to make a quick sale.
⭐ Real Reviews, Real Peace of Mind
Our reputation is built on over 700 independent reviews.
- Which? Trusted Traders: 4.9/5 (100% of customers recommend us)
- Google: 4.9/5 (from 250+ reviews)
- Checkatrade: 9.87/10 (from 360+ reviews)
“As a Commercial Construction Project Manager I cannot recommend highly enough the service and window installation that KJM carried out on my home… their communication and service was exemplary.” – KJM Customer Review
We are also a long-standing member of the Glass and Glazing Federation (GGF) and are Trading Standards Approved, so you are fully protected.
See the Difference for Yourself at KJM
Reading an article is one thing, but seeing and feeling the difference is another.
A uPVC window doesn’t feel the same as an aluminium one. The way they open and close, the texture of the finish, and the visual difference of the frame-width are all things you can only appreciate in person.
We have a wide range of both uPVC and aluminium window styles, including casement, sliding sash, and tilt & turn, at our extensive showroom in Andover.
Our non-commissioned, expert team can show you the technical differences, discuss your property, and give you honest advice on which material would be the best investment for you.
Your Next Steps
Ready to explore your options with a team you can trust?
- Get a Free Quote: Use our online quoting engine for an instant estimate.
- Book a Visit: Schedule an appointment to visit our showroom and compare both materials side-by-side.
- Ask an Expert: Call our team on 01264 359355 with any questions. We’re here to help.
- Email our sales team [email protected]
uPVC v Aluminium FAQs
While aluminium has a higher upfront cost, it’s best to think of it as a long-term investment. The material’s exceptional durability means it can last 40-50+ years, compared to 20-30 for uPVC. For many, the superior lifespan, slim-line aesthetics, and potential added value to their home make it a worthwhile investment.
This is a common myth based on old, first-generation products. Modern aluminium windows are now highly energy-efficient because they feature a “polyamide thermal break.” This is a strip of insulating material inside the frame that stops cold from transferring from the outside to the inside, effectively preventing condensation and keeping the room warm.
Generally, aluminium’s slim, sleek frames are the number one choice for modern homes and extensions. For period properties, high-quality uPVC is often a perfect fit. Modern uPVC is available in a huge range of heritage colours and realistic woodgrain finishes, including vertical sliding sash styles that preserve traditional character.
No. Modern aluminium windows are “powder-coated,” which is an extremely durable, baked-on finish that won’t flake, rust, or fade. Likewise, modern coloured uPVC windows are not the same as old, 1990s plastic. They use high-performance, bonded “foils” that are UV-stable and designed to look new for decades with minimal maintenance.
Both materials are exceptionally secure. An aluminium frame is inherently stronger due to the material’s rigidity. However, a window’s security truly comes from its locking mechanism, internal beading, and the quality of the installation. All KJM windows, whether uPVC or aluminium, are fitted with multi-point locking systems and meet stringent security standards.
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Mark Pearce is a highly experienced specialist in the double glazing industry, having built his knowledge from the ground up through hands-on experience in installation, manufacturing, sales, and business management. Beyond his role at KJM, Mark is a keen blogger, writer, and traveller, often sharing insights on the latest innovations in the home improvement industry.
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