Aluminium Vs Upvc Windows: The Best 2026 Guide

Aluminium vs uPVC windows — If you’re weighing up frame materials for a new build or a window replacement, aluminium and uPVC are the two options you’ll most often see compared. Both can look good and perform well — but they behave very differently over the 15-20+ year lifespan of a window, especially in South Africa’s climate. This guide compares them honestly, point by point, so you can make the right call for your own project rather than relying on generic marketing claims from either side.

Aluminium vs uPVC windows at a glance

The aluminium vs uPVC windows choice comes down to strength, looks, maintenance and cost. Aluminium frames are slimmer and stronger, carry more glass, and suit modern architecture; uPVC insulates well but frames are bulkier and can discolour over time. For most South African homes the aluminium vs uPVC windows decision favours aluminium for its durability, colour retention and contemporary finish, which is why aluminium vs uPVC windows comparisons increasingly land on aluminium.

A quick note on where we stand: Coetz™ manufactures and supplies aluminium windows and doors only, so we have an obvious commercial interest in this comparison. We’ve tried to be fair to uPVC’s genuine strengths below rather than present a one-sided case — the goal is to help you choose correctly for your climate and budget, not just to sell aluminium.

Strength
Appearance
Lifespan
Security
Maintenance
Cost
Weather resistance
Which should homeowners choose?
Why Choose Coetz™
Related products
Related articles
Frequently asked questions

Strength: aluminium vs uPVC windows

Aluminium has a significantly higher strength-to-weight ratio than uPVC. That extra structural strength means aluminium frames can be made noticeably slimmer than uPVC frames while still safely supporting the same size of glass pane. uPVC, being a plastic, needs thicker frame sections — and often internal steel or aluminium reinforcement bars — to achieve similar spans, which limits how large a single uPVC window or door pane can practically go before it needs extra support.

This matters more than it might seem for larger openings — wide sliding doors, floor-to-ceiling glazing, or oversized picture windows. Aluminium can span these openings with a single, relatively slim frame section. uPVC generally needs to break a large opening into smaller segments with additional frame members in between, which changes both the structural approach and the final look of the installation.

Appearance: aluminium vs uPVC windows

Aluminium’s slimmer profiles give a cleaner, more contemporary look with more visible glass and less visible frame — a big reason it’s the default choice in modern architectural design. It also takes a powder-coated finish well, opening up a wide range of durable colour options rather than the more limited white or foil-laminated woodgrain finishes typical of uPVC. uPVC frames are bulkier by design, which some homeowners prefer for a more traditional look, but it does mean less glass and more visible frame for the same opening.

Colour is a genuine point of difference too. Powder-coated aluminium finishes are baked on and highly durable, so the colour you choose at installation is the colour you’ll have decades later. uPVC’s white or foil-laminated finishes are more limited in range, and foil finishes in particular can peel or fade with prolonged sun exposure — another area where South Africa’s climate puts extra strain on the material.

Lifespan: aluminium vs uPVC windows

Aluminium does not rust, rot or degrade structurally over time, and a correctly powder-coated finish holds its colour for decades. uPVC is a plastic, and like most plastics it’s vulnerable to long-term UV exposure — over many years in strong sun it can discolour, become brittle, and in some cases warp slightly, particularly on north- and west-facing installations. In South Africa’s high-UV climate, this is a genuinely relevant difference, not a minor one.

Practically, this means a well-specified aluminium window installed today can reasonably be expected to still be structurally sound and visually presentable decades from now, with only routine cleaning. uPVC’s lifespan is more variable — it depends heavily on the quality of the specific product, the additives used to resist UV breakdown, and how much direct sun exposure the installation gets over its life.

Security: aluminium vs uPVC windows

Security in either material comes down mostly to the glass specification and the quality of the locking hardware, not the frame material alone — a well-specified window in either aluminium or uPVC, fitted with appropriate safety glass and good locks, will perform well. That said, aluminium’s inherent structural rigidity gives it a natural edge: it’s harder to flex or force at the frame itself, whereas lower-cost uPVC installations can be more vulnerable to forced entry at weaker points in the frame.

Don’t judge either material’s security on frame type alone — ask specifically about the glass specification (toughened or laminated safety glass makes a real difference) and the locking mechanism, regardless of which frame material you choose.

Maintenance: aluminium vs uPVC windows

Both materials are marketed as low-maintenance compared to timber, and in fairness, both largely deliver on that. The difference shows up over the long term: aluminium frames can usually be cleaned, resealed or even re-powder-coated if damaged, while uPVC frames are typically welded at the corners and are difficult or impossible to repair if cracked, warped or discoloured — the usual fix is full replacement of that frame.

Cost: aluminium vs uPVC windows

uPVC is often positioned as the more budget-friendly option upfront, and in many cases the initial purchase price is lower. The fairer comparison, though, is lifetime cost: a well-finished aluminium window bought once shouldn’t need frame replacement due to UV degradation, while a uPVC installation exposed to years of strong South African sun may need earlier replacement or repair. We’d rather you make this comparison with real numbers for your specific project than a generic industry statistic, so get in touch for a quote and weigh it against your own budget and timeline.

It’s also worth factoring in resale and renovation value. Aluminium’s clean, modern appearance tends to hold buyer appeal over time, while discoloured or warped uPVC frames on an older property can actually count against a sale, sometimes triggering exactly the kind of replacement cost the lower upfront price was meant to avoid.

Weather resistance: aluminium vs uPVC windows

This is where South Africa’s climate matters most. Coastal areas face salt-air exposure, which aluminium (with the correct marine-grade finish) handles far better than most materials. Inland and highveld areas face intense UV and large day-to-night temperature swings — conditions aluminium shrugs off structurally, while uPVC’s long-term UV resistance is more climate-dependent and product-quality-dependent. If your home faces direct sun for most of the day, this is a genuinely important factor to weigh, not just a marketing point.

Which should homeowners choose?

There’s no single right answer for every project — budget, architectural style and personal preference all play a role. But for South African conditions specifically, aluminium’s combination of UV stability, structural strength, slim modern sightlines and long-term repairability make it the stronger choice for most homeowners, which is why it’s the material Coetz™ has built its entire range around.

As a general rule: if your budget is tight and the installation faces minimal direct sun, uPVC can be a reasonable short-to-medium-term choice. If you’re building for the long term, want larger uninterrupted glass areas, or your home faces significant sun exposure — which describes most of South Africa — aluminium is the more resilient, lower-lifetime-cost option.

Why Choose Coetz™

Coetz Glazing supplies aluminium windows and doors directly to homeowners, builders, contractors and property developers — supply-only, made to order, with no installation middleman marking up the price.

Made to order — every unit is manufactured specifically for your order, standard size or custom.
Collection or delivery — collect from our Laser Park, Roodepoort premises, or arrange delivery. See the Delivery page for current options.
Supply-only, nationwide — Coetz™ supplies product only; installation is arranged separately by you or your contractor.
Trade and bulk orders — builders, contractors and developers can apply for a trade account.

Want the full picture on aluminium before you decide? Read our Ultimate Guide to Aluminium Windows in South Africa, or chat with a Coetz™ specialist on WhatsApp.

See real aluminium window sizes and specifications:

Frequently asked questions

Is aluminium or uPVC better for South African weather?

Aluminium generally performs better in South Africa’s high-UV, high-temperature-swing climate. It doesn’t degrade under sun exposure the way uPVC can over many years, and coastal-grade finishes handle salt air well.

Is uPVC cheaper than aluminium?

Often the upfront price is lower, but the fairer comparison is lifetime cost — aluminium’s durability and repairability can offset a higher initial price over the life of the window. Get a quote for your specific project to compare properly.

Does Coetz™ sell uPVC windows?

No. Coetz™ specialises in aluminium windows and doors only, manufactured to order in standard and custom sizes.

Which is more secure, aluminium or uPVC windows?

Security depends mostly on glass specification and lock quality in either material, but aluminium’s structural rigidity gives it a natural advantage against forced entry compared to lower-cost uPVC installations.

Can uPVC windows be repaired if they discolour or warp?

Usually not easily. uPVC frames are typically welded at the corners, so significant discolouration or warping usually means replacing the frame rather than repairing it. Aluminium frames are generally more repairable.

Ready to compare real options? Browse Coetz™ aluminium windows, or get in touch for a quote.

About Coetz™

Coetz™ manufactures premium aluminium windows and doors for homeowners, builders, architects and contractors across South Africa. Our products are manufactured to order and supplied directly to customers nationwide using genuine aluminium profiles and safety glass.

See also: aluminium vs wooden windows — another material comparison to help you choose the right frame.

Aluminium vs uPVC windows: which copes better with coastal salt air?

On the coast this is usually the deciding factor. Powder-coated aluminium handles salt-laden air well and can be recoated; uPVC does not corrode but can chalk and discolour under strong UV. For a sea-facing elevation the aluminium vs uPVC windows comparison tends to favour aluminium on appearance over time.

Does the aluminium vs uPVC windows decision change on large openings?

Yes, and this is where it changes most. uPVC needs bulkier profiles or steel reinforcement to stay rigid as spans grow, which eats into the glass area. Aluminium carries larger panes on slimmer sightlines, so on big openings the aluminium vs uPVC windows question is often settled by structure rather than preference.

Is the aluminium vs uPVC windows price gap the same over twenty years?

Not usually. uPVC is generally cheaper to buy, but the comparison narrows once you count refinishing, hardware replacement and the cost of replacing a unit that has warped or discoloured. Judged over the life of the building rather than at purchase, aluminium vs uPVC windows is a much closer call than the first quote suggests.

Getting aluminium vs uPVC windows right the first time

The enquiries that turn into clean, on-time projects nearly always arrive with the same handful of details settled. When you are pricing aluminium vs uPVC windows, these are the ones our estimators ask for.

The structural opening. Measure the brickwork opening rather than an existing frame, and check the reveal is square and plumb.
Configuration. Confirm the opening arrangement, which panes open, and which way they open before anything is manufactured.
Colour. Five finishes are stocked — black, white, bronze, charcoal and natural anodised — and some carry a premium.
Glass. Coetz™ glazes as standard with 6.38 mm clear laminated safety glass.
Supply only. Aluminium windows and doors are supplied, not installed, so allow for your own installer.

With that information we can turn aluminium vs uPVC windows around quickly and without a site visit in most cases. Where a detail is still undecided, we would rather quote aluminium vs uPVC windows both ways than reissue later.

Aluminium vs uPVC Windows: Which Is Better?