uPVC vs Aluminium Windows and Doors: A Side-by-Side Comparison

Stand in any builder’s merchant or scroll through a few double glazing suppliers online and you will see two materials dominating the conversation: uPVC and aluminium. Both have matured far beyond their early reputations. Today’s uPVC windows and doors no longer yellow and bow like those from the 90s, and aluminium windows and doors are no longer the cold, condensation-prone frames your grandparents remember. The choice is more nuanced, and the right answer depends on your home, climate, budget, and appetite for maintenance.

I have fitted, specified, and lived with both. What follows is a grounded comparison, the sort of detail you want before you sign off on a whole-house order and live with it for two decades.

What shapes the look and feel

The first thing people notice is sightlines. uPVC profiles are bulkier because they rely on thicker sections and internal reinforcement to achieve strength and insulation. Aluminium can achieve slimmer frames for the same structural span, which brings more glass and a cleaner, sharper look. In a south-facing living room, those extra millimetres can translate to noticeably more daylight and a better connection to the garden.

Colour and finish differ as well. uPVC has improved, with foiled finishes that mimic timber grains and a respectable palette of modern colours. Still, its surface reads as plastic up close. Aluminium can be powder-coated in thousands of RAL shades, matte or satin, even textured. If you want a deep charcoal that stays true for years, or you are matching architectural steelwork, aluminium wins. If you are aiming for a traditional cottage look without the price of timber, good uPVC with a woodgrain foil can work convincingly at typical viewing distances.

Hardware sits differently on each too. Aluminium systems integrate flush handles and minimalist hinges more gracefully, since the profiles are slimmer and more rigid. uPVC hardware is chunkier and sometimes sits prouder from the sash. On a period façade where symmetry matters, that difference can tip the balance.

Thermal performance and energy bills

The easiest mistake in this category is to assume material equals performance. In practice, the glass unit and the system design do most of the heavy lifting. A high-spec double glazed unit with warm-edge spacers, argon fill, and low-e coatings will push performance up regardless of the frame.

As a rule, uPVC frames have lower U-values out of the box because PVC is a poor conductor. It insulates naturally, and multi-chambered profiles add more still. Typical modern uPVC windows with quality double glazing reach whole-window U-values around 1.2 to 1.4 W/m²K, with triple glazing dipping below 1.0. Aluminium needs thermal breaks, usually polyamide, to decouple inner and outer skins. Twenty years ago that was a weak point, but modern thermally broken aluminium can achieve figures comparable to uPVC when paired with the right glazing. I have seen aluminium systems with triple glazing achieve 0.9 to 1.1 W/m²K as installed.

Condensation tells a story on winter mornings. uPVC frames resist it well due to their insulating cores. Aluminium, even with thermal breaks, can feel cooler to the touch, and if the glass spec is poor or ventilation is lacking, you might see frame-edge condensation. In practice, well designed aluminium windows and doors with warm-edge spacers and balanced ventilation rarely show persistent condensation in normal domestic use.

If you are chasing Passivhaus levels, both materials can get you there with the correct system and glass, but triple glazed uPVC is often the cost-effective route. If you are upgrading a typical semi with average masonry and loft insulation, either material with decent double glazing will represent a huge step up from old single glazed timber or early aluminium.

Strength, span, and what you can build

Here is where aluminium flexes. It is lighter and stronger than uPVC per section, which means it remains rigid across larger openings. If discover new window trends you are dreaming of a 6 metre run of sliding doors or slim-line bifolds with narrow interlocks, aluminium delivers. You can absolutely find uPVC sliders and bifolds, but the meeting stiles are bulkier, and the maximum panel size is usually smaller. When you push uPVC into large spans, you add steel reinforcement inside the frame, which counters some of its thermal advantage and adds weight.

For standard casement or tilt-and-turn windows up to moderate sizes, uPVC feels solid and works well. I have never had a problem on a typical 1.2 by 1.2 metre casement in good uPVC. For a 2.4 metre tall glazed door or a statement corner with minimal posts, I reach for aluminium every time. Wind loads on high-rise apartments or coastal homes also favour aluminium, which handles deflection better. A flexible frame leads to poor seals and rattles. A rigid frame keeps compression on the gaskets exactly where it needs to be.

Security benefits from stiffness too. Modern multi-point locking systems are excellent in both materials, but a rigid aluminium sash resists prying more consistently along its length. uPVC can meet the same security ratings when specified correctly, so check for PAS 24 or similar certifications rather than relying on assumptions.

Noise reduction and peace indoors

Glazing dominates acoustics. A 6.4 laminate pane with a 16 to 20 mm cavity and asymmetric build will out-perform a symmetrical double glazed unit by a wide margin, no matter the frame. That said, frame sealing and gasketing play a role. Well-engineered aluminium systems often use continuous gaskets with consistent compression, which helps. uPVC with modern seals is also strong here. If you live near a busy road or under a flight path, ask for acoustic glazing options and focus on airtight installation around the frame. I have seen mediocre foam jobs undo the benefit of expensive glass.

Lifespan, maintenance, and how they age

uPVC is largely maintenance-free. Wash it with soapy water a few times a year, avoid abrasive pads, and keep the weep holes clear. White uPVC resists UV well now that stabilisers have improved. However, darker foils can pick up surface scuffs that are hard to disguise, and repairs to damaged foil never blend perfectly. Over 20 to 30 years, expect some gasket replacement and hardware refresh.

Powder-coated aluminium is also low maintenance. The better coatings last decades, particularly marine-grade finishes in coastal areas. Minor scratches can be touched in with color-matched paint, and because the base material is metal, it holds its shape without creeping. Joints remain tight, and sash alignment tends to stay true over time.

One practical point: moving parts do not care about frame material. Hinges and locks need lubrication annually, and drainage channels clog if ignored. Most of the premature failures I see relate to neglected hardware rather than the frame itself.

Cost, budgeting, and value

At the entry level, uPVC windows and doors are typically 20 to 40 percent less expensive than aluminium equivalents, depending on region and supplier. For a whole-house replacement on a three-bed semi, that difference can run into the thousands. If you add premium finishes to uPVC, the gap narrows. If you add triple glazing, integrated blinds, or specialist coatings to aluminium, the gap widens.

Long-term value is not only thermal savings. Aluminium often holds a premium in resale for contemporary homes, especially where the slim frames contribute to the architecture. For traditional homes, buyers respond more to overall condition and fit than to the label. If you plan to stay put for a long time, choose the one that you will enjoy looking at and living with daily. The energy savings between two well-specified systems are usually modest compared with total household energy usage.

Sustainability and end-of-life

uPVC is a plastic derived from petrochemicals and chlorine chemistry. It is recyclable, and a growing share of modern uPVC profiles incorporate recycled cores with virgin skins for consistent surface quality. The recycling infrastructure has improved, though it is not yet universal everywhere. Its embodied energy per frame is lower than aluminium’s, but it can release pollutants if burned improperly at end-of-life. Responsible recycling avoids that.

Aluminium requires significant energy to produce from bauxite. The flip side is that it is infinitely recyclable, and recycled aluminium uses a fraction of the energy of virgin stock. Many leading systems already contain recycled content. If you can source from manufacturers who publish Environmental Product Declarations and use high recycled content, aluminium’s lifecycle profile looks strong.

From a durability standpoint, longer life equals fewer replacements. A well-made aluminium system can serve for 40 years or more. Quality uPVC can also reach 30 years plus. Poor installation or cheap hardware shortens either one, which is why choice of installer matters as much as material.

Weather, location, and specific conditions

Climate pushes choices in subtle ways. In cold, inland regions, uPVC’s innate insulation and the ease of achieving very low U-values with triple glazing make it attractive. In hot, sunny climates, dark aluminium frames can get hot to the touch but cope well structurally. With correct thermal breaks and good solar control glass, both perform.

Coastal areas deserve special mention. Salt air attacks everything. Aluminium needs a marine-grade powder coat and stainless or treated hardware. Do not skimp on this. uPVC avoids corrosion issues but still relies on metal reinforcement and hardware that can corrode, so the same caution applies. Between the two, I have seen aluminium with the right finish outlast budget uPVC near the sea.

High-rise or exposed sites call for aluminium’s rigidity and tighter tolerances. Farmhouses with occasional mud-spattered dogs and kids banging doors enjoy uPVC’s forgiving finish and easy cleaning.

Installation quality and the hidden details that decide outcomes

More performance is lost at the edges than people realise. A beautiful frame installed into a loose, uneven opening with gaps filled only by soft foam will leak heat, air, and noise. You want proper packers, airtight internal tapes, weather-resistant external tapes or sealants, and continuity with the wall’s own vapor and insulation layers. Check that your installer is not just a reseller but understands detailing. On a retrofit, insist on a site survey that checks reveal depths, lintel condition, cill details, and damp proof course alignment.

Adjustments after installation matter. New frames settle, gaskets compress, and sashes can go slightly out of square. A good installer schedules a follow-up visit to tweak hinges and locks. I wish more homeowners pushed for this, because a 20 minute hinge tweak can transform how a door seals in winter.

Doors: sliders, bifolds, and entrance sets

The window debate gets most of the airtime, but doors reveal the practical differences. Sliding doors in uPVC are fine for modest spans. For anything over about 3.5 to 4 metres with large panes, aluminium glides better, flexes less, and seals more consistently along the tracks. Slim interlocks around 20 to 35 mm are common in aluminium, while uPVC typically sits thicker.

Bifold doors benefit even more from aluminium. The stacking width, hinge precision, and long-term alignment all rely on rigidity. I have serviced many uPVC bifolds that drifted out of true after years of thermal cycling. Aluminium holds geometry better, which keeps the weather seals happy.

Entrance doors are trickier. You can get excellent composite or aluminium entrance doors that feel solid and resist warping. uPVC panel doors have improved, but the tactile feel and slam sound still broadcast the material. If the front door is a statement piece, look at aluminium or a good composite. If it is a secondary or utility entrance, uPVC is cost-effective and secure when specified with multi-point locks and laminated glass.

Style compatibility with the house you have

Modernist extensions with big openings love aluminium. The thin frames echo steel heritage looks without the thermal penalty. Grey and black powder coats pair well with brick, render, and timber cladding. If you are renovating a Victorian terrace with sash windows, good uPVC sash-lookalikes exist, complete with run-through horns and putty-line profiles, though aluminium heritage systems can also mimic steel or slim timber quite well. Planning departments sometimes care. In conservation areas, you might need timber or a very sympathetic aluminium system. uPVC can be a harder sell with conservation officers.

Inside the house, think about how frames sit against reveals. Deep uPVC frames can project more, which affects blinds and shutters. Aluminium’s slimmer depth can make flush reveals easier in some build-ups. These are small details, but every day usability lives in the check out double glazing unit options small details.

Working with double glazing suppliers and installers

Prices bounce around more than homeowners expect. One supplier may handle a premium uPVC line and a mid-tier aluminium line, while another flips that. Always compare systems on a true like-for-like basis: same glass spec, same hardware, same security rating, same trickle ventilation if required, and the same installation detail. When you talk to double glazing suppliers, ask for whole-window U-values, not just centre-of-glass figures. Ask about spacer types, gas fills, and whether they use drained and ventilated glazing rebates.

Lead times vary. uPVC can arrive in 2 to 6 weeks depending on colour, while bespoke aluminium in unusual colours or large sliders can take 6 to 12 weeks. If your project schedule is tight, build this into your plan. Delivery is only half the story. The best installers are booked ahead, and the team on the day matters more than the brand on the brochure.

Real-world scenarios that often decide the choice

A family renovating a 1980s detached house, aiming for warmer bedrooms and a quieter street side, typically ends up with uPVC windows and doors with high-spec double glazing. The cost leaves budget for loft insulation and a new boiler controller, which together cut bills more than a marginal window upgrade would have.

A couple building a kitchen-diner extension with a 5 metre opening to the garden often chooses aluminium sliding doors. The slimmer interlocks make the view, and the frame stays stiff under heat and cold. For side windows and utility doors, they might mix in uPVC to balance the budget without compromising the main feature.

A coastal bungalow replacement with large picture windows and tough wind exposure goes aluminium with a marine-grade finish, laminated solar control glass, and stainless hardware. The initial spend is higher, but maintenance is simple and performance holds through storms.

Common myths that need retiring

uPVC always yellows. Modern uPVC uses stable compounds and UV inhibitors. Cheap imports can still fade, but quality branded profiles keep their color for years.

Aluminium is always cold. With thermal breaks and good glazing, whole-window performance can match uPVC. Touch temperature is different from heat loss.

uPVC is flimsy. For ordinary window sizes, it is solid and secure. The problems show up mostly when you push spans beyond what the system was designed to do.

Aluminium is only for modern homes. Heritage aluminium systems with putty-line and slimline profiles can sit comfortably in traditional architecture, particularly in rear extensions or where planning allows.

A concise decision guide

Choose uPVC when you need solid thermal performance on a budget, your openings are standard sizes, and you prefer a maintenance-light solution with a traditional or neutral look. Choose aluminium when you want slim sightlines, large spans, or a crisp modern aesthetic, and you are willing to invest in a higher-spec, longer-lived system.

What to check on a quote before you say yes

Whole-window U-value, glass makeup, and spacer type. Security rating and hardware brand, plus hinge and lock warranties. Finish details: foil colour for uPVC or powder coat code and class for aluminium, including marine specification if relevant. Installation method, sealing tapes, cill and head details, and whether making good is included. Lead time, staged payments, and aftercare visit for adjustments.

Final thoughts from the job site

I have never seen a homeowner regret choosing frames that match the scale and character of their openings. The disappointments happen when someone forces a large span into a material that prefers smaller units, or when thermal promises ignore the glazing spec and the installation detail. If your project is standard windows and a couple of doors, uPVC windows and doors with a well-chosen glass package will serve you well for decades. If your heart is set on that wide, clean view or a slimline architectural profile, aluminium windows and doors justify their premium every time you open them and watch the garden pour into the room.

Either way, work with reputable double glazing suppliers who can explain their systems without jargon, and insist on an installer who cares about the edges as much as the centre. Your home will be warmer, quieter, and better looking for years to come.

Doorwins
Address: Office 11, Dearden House, W Gate, London W5 1BS
Phone: 020 8629 1250

Doorwins Windows and Doors has become among the best double glazing suppliers in London. We supply and professionally fit high-performance aluminium doors for modern homes and luxury developments.

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uPVC & Aluminium Styles: uPVC sash-style windows; uPVC front doors; roof lights. Aluminium slimline windows; aluminium bifold doors; roof lanterns. As a London double glazing manufacturer, we provide bespoke fabrication and fitting for residential and commercial projects, covering replacement windows, new-builds, extensions, and refurbishments.