Thermally broken windows can be a worthwhile choice for Western Australian homes, particularly when you want better control over indoor temperatures. However, they are not a blanket requirement for every property. Whether you need them depends on your location, home design and the energy performance your project must achieve.
If you are building or replacing windows in Perth or regional WA, understanding the frame is just as important as choosing the glass.
What are thermally broken windows
The term usually refers to windows with thermally broken aluminium frames. A material that conducts heat poorly separates the inner and outer aluminium sections, reducing heat transfer through the frame.
Standard aluminium conducts heat readily. A thermal break interrupts that pathway, helping the frame insulate more effectively. It works alongside the glazing, rather than replacing the need to select suitable glass.
Are thermally broken windows compulsory in WA?
There is no blanket requirement for every WA home to use thermally broken aluminium windows. Compliance depends on the applicable building requirements and the performance of the proposed design.
WA introduced updated residential energy efficiency requirements from 1 May 2025, including the equivalent of a 7-star NatHERS thermal performance standard for new homes. A home’s energy rating considers the building as a whole; it does not prescribe one window frame material for every project.
Thermally broken windows may help a design achieve its required performance, but other specifications may also be suitable. Ask your energy assessor and building surveyor to confirm the requirements for your project before ordering.
Why consider thermally broken windows in Perth
Windows influence how comfortable your home feels and how much heating or cooling it needs. In Perth, the aim is to manage summer heat while retaining warmth during cooler weather.
Improved frames can help reduce heat flowing between indoors and outdoors. However, the result also depends on window size, glazing, shading and orientation.
For example, a large west-facing window needs careful control of afternoon sun. A thermal break improves the frame, but external shading and suitable solar-control glass are still important. WA Government guidance specifically highlights controlling sunlight through east- and west-facing windows in the southern half of the state.
Does the answer change across Western Australia
Yes. Window selection should reflect your local climate rather than treating WA as one uniform environment.
In cooler southern locations, retaining indoor warmth deserves close attention. In northern WA, limiting heat gain is the main priority. Shading, ventilation and glazing specifications need to support those different goals.
A window package that suits a Perth home may therefore need adjustment for a property in the Kimberley or a cooler southern town. Climate-specific design advice helps identify where an upgrade will make the most difference.
Are thermally broken windows the same as double glazing
No. Double glazing describes two panes of glass separated by a sealed gap. A thermal break describes an insulating separation within the frame.
A double-glazed window can have a standard aluminium frame, while a thermally broken frame can be supplied with different glazing options. Check both parts of the specification.
When comparing quotes, ask for:
- Whole-window U-value: a lower value means less heat transfer through the complete window.
- Solar heat gain coefficient, or SHGC: this indicates how much solar heat passes through; the appropriate value depends on orientation and climate.
- The exact frame and glass combination being supplied.
Compare whole-window ratings rather than a glass-only figure.
Should you replace existing windows straight away
Start by identifying what is making your home uncomfortable. Draughts around closed windows, strong afternoon sun and heat transfer through the window require different responses.
Sealing gaps and adding suitable external shading may be useful first steps. If you are already planning a substantial renovation or window replacement, compare the additional cost of thermally broken frames within the complete project.
Installation matters too. Gaps around a new frame can allow unwanted air movement and undermine comfort, even when the window itself performs well.
Are thermally broken windows worth the cost
They deserve consideration when improved comfort and lower heating or cooling demand are priorities. Whether the additional investment is worthwhile depends on the quoted price, the performance improvement and how you use your home.
Ask your assessor to compare window options within your actual design. This gives you a stronger basis for deciding than a general promise about energy savings or payback.
Choosing windows for your WA home
Thermally broken windows can contribute to a more comfortable Western Australian home, but the best result comes from selecting the frame, glass and shading together.
Before committing, request the complete window specifications and have them checked against your home’s orientation, climate and energy assessment. That way, your window choice supports both your comfort goals and your project’s requirements.