Clearfox Windows · Adelaide window specialists
Thermally Broken Windows: Worth It in Adelaide?
By Clearfox Windows · Published 8 October 2026
What are thermally broken windows, and are they worth it in Adelaide?
Thermally broken windows are aluminium windows with an insulating barrier built into the frame, so heat can’t flow straight through the metal. In Adelaide they are worth considering when you want the slim look of aluminium with better comfort, especially paired with double glazing on west-facing rooms, cold Hills homes or condensation-prone bedrooms.
Aluminium is the most common window frame in Adelaide. It is strong, slim and economical, and it suits the modern and coastal homes found right across the metro area. Its weakness is that aluminium conducts heat very readily. A thermal break deals with that weakness. This guide explains how, where it makes a real difference, and when another frame might suit you better.
How a thermal break works
A standard aluminium frame is one continuous piece of metal from the outside face to the inside face. On a hot afternoon, the outside of the frame heats up and that heat travels straight through to the room side. On a cold morning, the reverse happens: the inside of the frame gets cold, and moist indoor air can condense on it.
A thermally broken frame splits the profile into an outer and an inner section, joined by a material that conducts heat poorly, typically a reinforced polyamide strip or a poured-and-debridged resin. The two metal halves never touch, so heat has to cross the insulating barrier to get through.
The result is a frame that:
- Conducts noticeably less heat between outside and inside.
- Stays warmer on the room side in winter, which reduces condensation on the frame.
- Feels less hot to the touch on a sunny afternoon.
Thermally broken aluminium windows vs standard aluminium
| Standard aluminium | Thermally broken aluminium | |
|---|---|---|
| Heat flow through frame | High | Noticeably lower |
| Condensation on frame | More likely on cold mornings | Less likely |
| Look | Slim sightlines | Slim sightlines, slightly deeper profile |
| Glazing | Single or double | Usually paired with double glazing |
| Cost | Lower | Higher, itemised on the quote |
The price difference depends on the window system, size and style, so we show it on the quote rather than quoting a percentage. As a typical guide for Adelaide homes, aluminium double-glazed windows run $1,800–$5,500 per opening fitted, with thermally broken systems generally towards the higher part of what you would pay for aluminium.
Why the frame matters as much as the glass
It is easy to focus on the glass because it is the biggest surface. But windows are rated as a whole: frame and glass together. A high-performance double-glazed unit in a frame that freely conducts heat leaves a weak path around the edge of every window.
That is why published whole-window figures are the honest comparison. The whole-window U-value (lower is better insulation) and the solar heat gain coefficient (lower lets in less solar heat) both reflect the frame. Our WERS window energy ratings explainer shows how to read them. Where the product we quote carries published figures, we pass them on with the quote.
Where thermal breaks make the biggest difference in Adelaide
West- and north-facing living areas
Adelaide’s summer afternoons push a lot of heat into west-facing rooms. A thermally broken frame, paired with double glazing and a suitable Low-E coating, reduces how much of that heat reaches the room. See our guide to Low-E glass for Adelaide’s climate.
Bedrooms with winter condensation
Cold aluminium frames are a common source of condensation, mould on sills and peeling paint. A thermal break keeps the inner frame warmer, which helps. Ventilation still matters too; our guide on how to stop condensation on windows covers both sides.
Adelaide Hills homes
Stirling, Aldgate, Bridgewater and Mount Barker have colder winters than the plains. Thermally broken frames are a sensible step up there. Many Hills properties are also in bushfire-prone areas, where the Bushfire Attack Level can dictate frame and glass choices; your BAL assessment and builder or certifier confirm what applies.
New builds with an energy target
New homes in South Australia must meet the NCC 2022 energy-efficiency provisions, adopted from 1 October 2024, including a 7-star NatHERS minimum. Window performance feeds into that assessment. If the assessor needs better-performing windows but you prefer aluminium, a thermally broken system is often the way to get there.
Where standard aluminium is still fine
Thermal breaks aren’t needed everywhere. Standard aluminium can be a reasonable choice for:
- Laundries, garages, storerooms and other rooms that aren’t heated or cooled.
- Small windows where the frame area is minor.
- Tight budgets where the money is better spent on double glazing for the main living areas first.
Coastal homes also need the right finish and hardware regardless of thermal break; our guide to windows for coastal Adelaide homes covers salt exposure.
Thermally broken aluminium vs uPVC and timber
uPVC and timber are naturally poor conductors of heat, so they don’t need a thermal break. They generally insulate well without one. Thermally broken aluminium closes much of the gap while keeping aluminium’s slim profile, strength for large openings, and wide range of colours.
- Choose thermally broken aluminium for slim sightlines, large sliding units, contemporary styling and a strong, low-maintenance frame.
- Choose uPVC when insulation and airtightness are the top priority and a slightly chunkier frame is fine.
- Choose timber for character homes, heritage settings or where the look of timber matters, accepting periodic re-coating.
Our aluminium vs uPVC vs timber comparison goes deeper on each.
Questions to ask on your quote
- Is the frame thermally broken, and what type of thermal break does it use?
- What is the published whole-window U-value and SHGC for each window?
- What glass specification is included (Low-E, argon, laminated, toughened)?
- What finish is used, and does the manufacturer recommend it for your exposure (for example, near the coast)?
- What warranty terms does the manufacturer provide, and what workmanship terms are in the written quote?
Related services
Clearfox Windows supplies and installs aluminium windows, including thermally broken systems, along with double glazing and energy-efficient windows across Adelaide metro and the Adelaide Hills.
Frequently asked questions
What does thermally broken mean on a window?
It means the aluminium frame is split into inner and outer sections joined by an insulating material, so heat can’t flow straight through the metal. The frame conducts noticeably less heat and stays warmer on the inside in winter.
Are thermally broken windows worth it in Adelaide?
They are worth considering for living areas facing the afternoon sun, bedrooms that get condensation, colder Adelaide Hills homes and new builds with an energy target. For laundries, garages and rarely used rooms, standard aluminium is usually fine.
Do thermally broken windows stop condensation?
They reduce it by keeping the inner frame warmer, so moist air is less likely to condense on it. Ventilation, exhaust fans and good glazing also play a part, so a thermal break is one piece of the solution rather than the whole answer.
How much more do thermally broken aluminium windows cost?
They cost more than standard aluminium, and the difference depends on the window system, size and style. As a typical guide, aluminium double-glazed windows run $1,800–$5,500 per opening fitted in Adelaide, and your quote itemises the thermally broken option.
Is thermally broken aluminium as good as uPVC?
uPVC generally insulates better because the material itself is a poor conductor of heat. Thermally broken aluminium narrows the gap while keeping slim sightlines and the strength for large openings. Comparing published whole-window U-values is the fairest test.
Do I need double glazing with a thermally broken frame?
They work best together. A thermal break improves the frame and double glazing improves the glass, and the window is only as good as its weakest path for heat. Most thermally broken systems are designed to carry double glazing.
Get an aluminium windows quote
Want to see standard and thermally broken options side by side? Request a quote or call 0468 038 136. We’ll get back to you within 24–48 hours, measure on site for free, and give you a written, itemised quote.