Why Standard Aluminium Frames Are Not Enough for Melbourne's Best Homes
Thermally broken windows for Melbourne projects require frame performance that supports serious specification review. Standard aluminium offers slim, slight lines and strong spans, yet it conducts heat readily and can become very cold in winter. As heat passes through the frame, internal surfaces can follow below the dew point, causing condensation around glass edges.
For premium homes, whole-window U-values depend on glass, spacers, frames, seals, installation and junctions. Arch Windows supply & install thermally broken aluminium windows for projects needing durability, large openings and comfort.
What is a Thermally Broken Window?
A thermally broken window uses a polyamide strip to separate the inner and outer aluminium profiles, interrupting the heat conduction path through the frame.
Instead of one continuous aluminium section carrying heat from outside to inside, the frame is separated by a low-conductivity barrier. Polyamide conducts heat far less than aluminium, reducing thermal bridging through the frame. This improves comfort near glass, lifts whole-window performance, and reduces condensation risk.
Indicative values:
| Window System | Indicative Whole-Window U-Value |
|---|---|
| Standard aluminium double glazed | ~5.5 W/m²K |
| Thermally broken double glazed | ~2.2 W/m²K |
| Thermally broken triple glazed | ~1.0 W/m²K |
Thermal break technology has long been used across colder European markets, where aluminium systems need higher thermal resistance without losing sharp architectural lines.
Thermally Broken Aluminium vs. uPVC vs. Timber
uPVC, timber and thermally broken aluminium all outperform standard aluminium frames, but each material suits a different project type.
uPVC performs well thermally at a lower entry price, although its frame sections can appear heavier on premium homes. Lower-grade products might get discoloured or move over time. Timber offers strong thermal performance and natural character, with higher upfront cost and ongoing finish maintenance.
Thermally broken aluminium sits in the premium specification category. It gives architects slim sightlines, large openings, stable powder-coated finishes, and long service life. It suits non-rectangular openings, large sliders, upper-floor windows, and facades where both appearance and engineering matter.
Arch Windows thermally broken aluminium windows for Melbourne new builds, renovation projects and architect-led upgrades. Configurations can include fixed, awning, hinged, sliding and lift-and-slide, double-hung, and larger custom openings.
Glazing options often include double glazing, triple glazing, Low-E glass, argon, acoustic laminates, low-iron glass and privacy glass. Frame finishes can be customised across powder-coated colours.
Each system should be selected around orientation, glazing area, acoustic needs, wind exposure, bushfire considerations and target energy rating. Arch fabricates from Rowville, with system names, profile depths, hardware details and lead times confirmed during consultation.
For glass-led performance guidance, see Arch’s Double Glazed Windows in Melbourne page.
Performance Data You Can Trust
ALSPEC provides performance data for aluminium window and door systems, including thermal performance, solar heat gain, acoustic ratings, WERS status, AS2047 compliance, panel sizing and lead times.
| PERFORMANCE AREA | ALSPEC DATA |
|---|---|
| Whole-Window Thermal Performance | Approx. 3.0–4.0 W/m²K for standard double-glazed aluminium systems, as low as 1.7–2.9 W/m²K for thermally broken double-glazed systems, and approx. 1.0–1.8 W/m²K for thermally broken triple-glazed systems. |
| Solar Heat Gain | SHGC values range from 0.30–0.60 for standard double-glazed aluminium systems, 0.16–0.63 for thermally broken double-glazed systems, and 0.15–0.40 for thermally broken triple-glazed systems. |
| Acoustic Performance | Acoustic ratings range from Rw 30–34, Rw 35–40, and Rw 40–45, depending on the selected aluminium system and glazing specification. |
| Energy Rating Status | WERS Rated |
| Compliance Status | Tested to AS2047 |
| Size Guidance | Maximum sizing depends on the selected system. Thermally broken double-glazed systems are listed up to 4500mm H x 2400mm W, while triple-glazed systems remain subject to engineering review. |
| Lead-Time Guidance | Lead time is approx. 4 to 6 weeks, or 8 to 10 weeks, depending on system type and glazing specification. |
When Thermally Broken Windows Are The Right Choice?
Thermally broken aluminium suits premium projects where standard aluminium would compromise comfort, condensation control, energy modelling or design intentions.
It is often specified for passive house and near-passive builds, NCC 7-star and 8-star homes, large glazing areas and exposed sites across Mt Macedon, Olinda, the Dandenongs, Mt Eliza, and the Mornington Peninsula.
For clients planning a 30-year window lifespan, the value case extends past energy use. It includes comfort near glass, lower condensation risk, durable finishes, and stronger resale appeal.
Investment and Lead Times
Thermally broken aluminium windows usually cost more than standard double-glazed aluminium. Many projects allow for a 30% to 60% premium, with final pricing affected by size, glass type, configuration, finish, access and site conditions.
Lead times must be confirmed against Arch Window’s current production schedule. For early feasibility, system selection, and specification guidance, Arch can review drawings, glazing areas, orientation, and performance targets.
Frequently Asked Questions
1. What is the difference between thermally broken and standard aluminium windows?
Standard aluminium has a continuous metal frame that conducts heat readily. Thermally broken aluminium separates inner and outer frame sections with a low-conductivity polyamide barrier.
2. Are thermally broken windows worth the extra cost in Melbourne?
They are often worth specifying for premium homes, large glazing areas, exposed sites, and higher energy targets where standard aluminium can reduce whole-window performance.
3. Can thermally broken windows be triple glazed?
Yes. Thermally broken aluminium systems can usually have double or triple glazed units, subject to frame capacity, panel load, hardware, and project requirements.
4. Do thermally broken windows stop condensation?
They can reduce condensation risk by raising internal frame temperatures, but room humidity, ventilation, installation quality, and glass specification still affect condensation behaviour.
5. What U-value should I look for in Melbourne?
Lower whole-window U-values generally support stronger performance, Arch confit, suitable targets using NatHERS modelling, orientation, glazing area, and selected frame system.
6. How Long Do Thermally Broken Aluminium Windows Last?
High-quality thermally broken aluminium windows are built for long service life with suitable finishes, correct installation, compliant drainage, and regular cleaning.
Contact us
On premium Melbourne builds, the frame choice affects window schedules. Thermally broken aluminium gives architects and owners clean sightlines, larger openings and stronger internal comfort without returning to standard aluminium limits. Arch can review drawings, orientation, glazing sizes and performance targets before recommending a suitable system.