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Aluminium windows: the complete 2026 guide (thermal break, finishes, prices)

Thermal-break aluminium windows: how they work, which profiles to choose, finishes, real prices, and when to prefer them over PVC.

aluminiumguidepillarthermal-break

Mirko Vanzo: Author
2 May 2026: Published
12 May 2026: Updated
13 min: Reading time

Reading time

13 min

Aluminium windows cover roughly 20-25% of the European residential market and a much higher share of contemporary commercial and architectural projects. They’re the natural choice for anyone who wants slim frames, large glazing, modern design, and virtually unlimited durability. They’re also the choice that’s less “default”, because they typically cost 20-30% more than the equivalent PVC — so they need to be chosen with a clear reason in mind.

This guide explains how thermal breaks actually work, which profile systems matter on the Italian and Albanian markets, and in which cases aluminium’s higher cost translates into real value.

1. Why aluminium in windows

Aluminium in windows has five concrete technical strengths:

Mechanical strength: aluminium’s strength-to-weight ratio allows slim frames that can still carry large panes of glass. A 3×2.5 m sliding sash can be built in aluminium; in PVC it’s pushing the limits of structural integrity.
Durability: aluminium naturally develops an oxide layer that protects it from corrosion. Qualicoat powder coating adds a further layer of protection that lasts 40-50 years under normal conditions.
Dimensional stability: unlike timber (which expands with humidity) and, to a lesser extent, PVC (which has a higher coefficient of thermal expansion), aluminium holds its dimensions even through significant temperature swings. This matters for very large windows and for areas with strong day/night temperature swings.
Total colour customisation: any RAL shade, anodised finishes, stainless-steel effect, Corten effect, dual-colour (one colour outside, another inside) without significant premiums.
Recyclability: aluminium is 100% recyclable, indefinitely, while retaining the same properties. It’s one of the most sustainable materials over the long term.

The historic weak point was thermal insulation — aluminium is a conductor. This weakness has been solved with the thermal break, and today a premium aluminium window insulates as well as a standard PVC one.

2. Thermal breaks explained properly

The thermal break is the heart of a modern aluminium window. Without a thermal break, aluminium is unusable for residential use in European climates.

How it works

A thermal-break profile is made up of:

[External aluminium profile] — [Insulating polyamide bar] — [Internal aluminium profile]

The polyamide bar (PA66, a technical plastic reinforced with glass fibre) is 24-34 mm wide and interrupts the thermal bridge between outside and inside. Heat can still cross the bar to some extent (polyamide isn’t a super-insulator), but the heat flow is reduced by 80-90% compared with “cold” aluminium (without a thermal break).

The codes that matter

Code	What it means	Typical range
Uf	Frame-only transmittance	2.8 (old, no thermal break) - 1.2 (premium thermal break)
Uw	Whole-window transmittance	1.4-1.0 W/m²K with a modern thermal break
Polyamide bar	Width in mm	24/28/34 mm — wider = more insulating
Air permeability class	UNI EN 12207	Class 4 = top

The difference between “cold” and “thermal-break” aluminium

Never fit aluminium without a thermal break in a residential setting. Interior condensation in winter is guaranteed: the cold profile chills the humid air that touches it, and water forms on the metal parts. The result: mould, dripping, a window that soaks the surrounding walls.

All serious residential aluminium today is thermal-break. Check the Uf transmittance class declared on the profile’s technical data sheet: below 2.0 W/m²K means a decent thermal break.

3. Profile systems on the Italian and Albanian markets

For aluminium windows in Italy and Albania, several reliable systems are available:

Schüco (Germany) — global top-of-range, AWS 70/75/90, FWS curtain walling
Reynaers (Belgium) — MasterLine 8/10, SlimLine 38, highly customisable
Aliplast (Italy) — Genesis, Imago, Ultraglass
Domal (Italy)
LMT Aluminium systems — the 70/71/91/92/93 range we use at LMT

The LMT Aluminium systems (what we work with)

System	Profile	Uf	Typical use
LMT 70	70 mm, 24 mm thermal break	2.0 W/m²K	Entry premium, standard windows
LMT 71	71 mm, 28 mm thermal break	1.8 W/m²K	Premium standard, medium sliding doors
LMT 91	91 mm, 34 mm thermal break	1.4 W/m²K	High efficiency, class A
LMT 92	92 mm, 34 mm thermal break	1.3 W/m²K	Lift-and-slide doors, large glazing
LMT 93	93 mm, 34 mm thermal break	1.2 W/m²K	Passive-house ready

The 91-93 systems with triple glazing reach Uw 1.0-1.2 W/m²K, values comparable to a good PVC window.

4. Types of opening

Aluminium offers more opening types than PVC because it’s structurally stronger:

Tilt-and-turn (casement)

The standard opening. One or two sashes that open inward on a rotating hinge, with a tilt position for ventilation. Works well up to 80×140 cm for a single sash.

Standard sliding

The sashes slide on parallel tracks, one in front of the other. Optimises interior space (the sash doesn’t intrude into the room). Limitation: one of the two sashes is always fixed when the other is open. Good up to 250 cm total width.

Lift-and-slide

The evolution of the sliding door. The sash lifts 2-3 mm when opened (reducing friction with the track) and drops when closed (pressing the gasket against the frame for a perfect seal). Allows heavy sashes up to 400 kg, widths up to 6 metres, and excellent water/wind resistance. This is the architectural choice for glazing opening onto gardens, terraces and porches. It costs 80-130% more than a standard sliding door, but in a kitchen or living room it transforms the space.

Pivot (centre-pivot)

An opening that rotates on a horizontal axis, typical of tall, narrow windows or contemporary architectural studios. Allows large glazed surfaces without separate sashes.

Curtain walling

For prestige commercial and residential projects: the entire façade becomes a continuous glazed surface held by an aluminium structure. Requires specific systems (Schüco FWS, Reynaers CW) and design integrated with the building.

5. Glass for aluminium: the same principles as PVC, with a few specifics

The glass selection criteria are identical to PVC (see the PVC guide), but with two specifics:

Large panes (over 2.5 m²)

Very large panes must be toughened or laminated for safety reasons, under UNI 7697. On a 3-metre lift-and-slide patio door, toughened or laminated 6/12/6 glass is the minimum. It costs 15-25% more but is mandatory.

Solar-control glass

On aluminium windows for houses with large glazed surfaces facing south or west, the amount of solar heat gain in summer can create overheating problems indoors. Solar-control glass (Pilkington Suncool, Saint-Gobain SGG Cool-Lite) offers:

High light transmission (70-80%) — light gets through
Low solar factor (0.30-0.40) — 60-70% of solar heat is blocked

It costs 10-20% more than standard glass, but on a 10-15 m² south-facing façade, the difference in summer overheating is huge (5-10°C cooler indoors).

6. Finishes and colours

One of the reasons to choose aluminium is colour freedom. The available finishes:

Powder coating

The market standard. Thermosetting Qualicoat powder, applied electrostatically and cured in an oven at 180-200°C. It guarantees:

Uniform thickness of 60-80 microns
UV resistance of 40-50 years without significant colour change
Any RAL shade available (including specific codes)
Finishes: gloss, satin, matt, textured
Resistance to scratching, salt exposure and weathering

2026 market standard: Qualicoat class 2 certification (high UV resistance) or Qualicoat Seaside (for coastal areas).

Anodised

An electrochemical treatment that creates a controlled oxide layer on the surface. Characteristics:

Metallic appearance (silver, bronze, gold, black anodised)
Chemical and mechanical resistance
Thickness of 15-25 microns
More expensive than powder coating
An industrial/minimal look much valued in architecture

Dual-colour (different inside/outside)

Aluminium allows a different colour outside (e.g. matt black RAL 9005) and inside (e.g. white RAL 9010) with no visible joins, thanks to the polyamide bar that separates the two sides of the profile. Premium: 10-20%. Practical rationale:

Dark exterior for architectural integration
Light interior to visually enlarge the rooms

Special finishes

Wood-effect: a heat-fused film with realistic grain. Premium of 15-25%. Indistinguishable from timber at 2 metres.
Corten effect: a controlled, oxidised surface, industrial look.
Stainless-steel effect: gloss or brushed, for minimalist projects.

7. Real aluminium prices

The 2026 figures for the Italian and Albanian markets:

Market reference prices, supplied and installed (UNI 11673)

The figures below are indicative market benchmarks for a window supplied and fitted, drawn from the general market — they aren’t LMT’s own installed offer. In Italy, LMT supplies the window; installation is carried out by your own installer. In Albania, LMT can also carry out the fitting. Use these figures as a general reference and confirm your actual cost via a quote.

Type	Typical size	Indicative price (€)
Window, 1 sash, LMT 70, double glazing	60×120 cm	380-550
Window, 2 sashes, LMT 70, double glazing	120×140 cm	680-980
Window, 2 sashes, LMT 92, triple glazing	120×140 cm	980-1,400
Patio door, 1 sash, LMT 70, double glazing	80×220 cm	780-1,150
Sliding door, 2 sashes, LMT 71, double glazing	240×220 cm	1,800-2,500
Lift-and-slide, 2 sashes, LMT 92, triple glazing	300×230 cm	3,500-5,500

Per square metre: €500-900/m² installed for the standard-premium range. Over €1,000/m² for curtain walling and special projects.

What affects the price of aluminium

Profile system (70 → 92 = +30-50%)
Double vs triple glazing (+15-30%)
Standard vs laminated/toughened glass (mandatory for large spans) (+15-25%)
Tilt-and-turn vs lift-and-slide (+80-130%)
Finish: standard white vs specific RAL (+5-10%), anodised (+15-25%), wood-effect (+20-30%)
Dual-colour (+10-20%)
Solar-control glass (+10-15%)

When premium aluminium makes economic sense

It costs more than PVC, but in certain cases it’s the more rational choice even economically:

Large glazing (over 4-5 m²): PVC has structural limits, and at those sizes, PVC with heavy reinforcement costs almost as much as aluminium
Long service life (prestige homes, historic buildings): 80-100 years of durability instead of 40-50
Direct marine exposure: anodised or Qualicoat Seaside coated profiles hold up better over decades of salt exposure
Refurbishment of heritage-listed façades: in some cases the local heritage authority accepts wood-effect aluminium but not white PVC

8. Installation: the same as PVC, with a few specifics

Installation of aluminium windows follows the same UNI 11673 standard covered for PVC. The technical specifics:

Thermal seal at the sub-frame

Aluminium still conducts some heat, even with a thermal break. The junction with the sub-frame needs particular care:

High-density closed-cell polyurethane foam
illbruck/Tescon tapes, external and internal
Sometimes extra-insulating EPS strips to reduce the residual thermal bridge

Loads on large sliding doors

A lift-and-slide sash can weigh 300-400 kg. The sub-frame beneath it must be structurally adequate — sometimes preliminary masonry work is needed. Check with your installer before signing off, to confirm your opening is compatible.

Lift-and-slide thresholds

Modern lift-and-slide doors have low thresholds (8-15 mm from the floor) for accessibility. They require specific preparation of the screed: the finished exterior floor level often needs lowering to avoid a negative step.

9. Maintenance

Aluminium is the most “set and forget” of window materials:

Cleaning the profile: warm water and neutral detergent, once or twice a year
Lubricating the hardware: specific oil once a year, the same as PVC
Gaskets: the same care as PVC
Coating: no maintenance required for 30-40 years under normal conditions

No periodic repainting as with timber, no special care needed. Anodised aluminium is even more stable and lasts practically forever.

10. When to choose aluminium over PVC

Let’s sum up the real cases where aluminium wins:

✅ Choose aluminium if:

You want slim frames and large glazing (over 2.5 m wide)
You need a lift-and-slide or pivot opening
You have curtain walling or contemporary architectural projects
You’re in a coastal area with heavy salt exposure (PVC performs well beyond year 5, but aluminium performs better)
You want specific RAL colours, dual-colour finishes, anodised
You’re building a “for life” house meant to last 60+ years
Slim frame aesthetics matter as much as thermal performance
You’re working on a commercial building or offices

❌ Choose PVC if:

You have a tight budget with high performance requirements
It’s a standard replacement in a flat
The windows are of normal size (under 2.5 m wide)
Maximum insulation per euro spent is the priority
Frame design isn’t critical

❌ Consider timber or timber-aluminium if:

The building is heritage-listed with restrictions
Warm interior aesthetics are the priority
You have a high budget (50% more than PVC)
You’re prepared for periodic maintenance (timber) or the extra cost (timber-aluminium)

Quick aluminium FAQ

Is aluminium “cold”? Only aluminium without a thermal break. With a modern thermal break, the surface temperature of the inner frame in winter is very close to room temperature (a difference of 2-4°C), and condensation doesn’t form. “Cold” aluminium was the kind used in the 1960s-80s; it’s no longer used in residential settings.

How long does aluminium actually last? 80-100 years of structural life. The coating/anodising may need restoring after 40-50 years under severe conditions (direct marine exposure). The profiles themselves are practically eternal.

Can aluminium have a realistic wood finish? Yes, Qualicoat Decoral heat-fused films with realistic grain. At 1-2 metres’ distance, the effect is indistinguishable from timber. Cost: +20-30% compared with a plain RAL coating.

Does it work in climate zone E/F (Trentino, inland northern Albania)? Yes, with the 91/92/93 system plus triple glazing. Uw 1.0-1.2 W/m²K is adequate even for climate zone F. For Passive House certification, the 93 system plus specific glazing is needed (Uw 0.8).

Can I have aluminium inside and PVC outside (or vice versa)? No, there’s no genuine hybrid system of that kind. For an aluminium exterior look combined with a warm timber interior, there are timber-aluminium systems (Internorm, Drutex, F&F, Tecnal): solid timber inside, aluminium shell outside. Cost: 40-60% more than the equivalent PVC.

How does recyclability work in practice? Unlike PVC, aluminium has a mature recycling chain. At end of life, an aluminium window is dismantled, the aluminium parts are 100% remelted, and the polyamide and glass parts go into specific recycling streams. Its environmental impact is amortised over 80-100 years of service life, making it one of the most sustainable materials.

Want to know if aluminium is right for your project? Request a quote and note the dimensions of your openings on the form: we’ll tell you whether PVC or aluminium is the more rational choice for your specific case.