Article Highlights

• Thermally broken frames reduce heat transfer, helping Perth homes stay cooler in summer, warmer in winter and more energy efficient year-round.
• Pairing thermally broken frames with double glazing delivers superior insulation, lower U-values and improved overall window performance.
• Key benefits include lower energy bills, reduced condensation, greater indoor comfort and better noise reduction, making them a smart long-term investment.
• Designed for Perth’s climate, thermally broken aluminium windows and doors perform well in extreme heat, mild winters and coastal conditions while supporting modern energy-efficiency standards.

If your home feels too hot in summer, too cold in winter or difficult to keep comfortable without running the air conditioner, your windows and doors could be part of the problem.

Thermally broken windows and doors are designed to reduce heat transfer, helping Perth homes stay more comfortable year-round. In this guide, we explain what thermally broken means, how it works with double glazing and why it can be a smart investment for energy efficiency, comfort and long-term performance.

What Does Thermally Broken Mean?

Standard aluminium window and door frames are made from a single piece of metal running from the outside of your home to the inside. Aluminium conducts heat extremely well, which means during a Perth summer, heat from outside travels straight through the frame and into your living spaces. In winter, the warmth from inside your home escapes the same way.

A thermally broken frame solves this by splitting the aluminium into two separate sections, with a strip of low-conductivity material (typically a reinforced polyamide) bonded between them. This strip acts as a thermal barrier, significantly slowing heat transfer through the frame and helping you get the best out of your aluminium systems.

The result is a window or door frame that keeps the outside temperature on the outside, where it belongs.

How does it work alongside double glazed window panes?

Double glazing is to glass what thermally broken is to aluminium windows.

Double glazed windows use two panes of glass separated by a sealed air or gas gap, which reduces heat passing through the glass itself, creating a highly effective thermal barrier that traps warmth in your home during winter. The thermally broken frame then addresses heat transfer through the frame. Learn more about the difference between double-glazed and single-glazed windows in our news section.

Together, they cover the entire window, allowing you to achieve maximum energy efficiency. That matters because a standard double-glazed window in a non-thermal aluminium frame still has a weak point: the frame conducts heat even when the glass doesn’t.

To put some numbers to it, whole-window U-values (a measure of how much heat passes through) compare like this:

The lower the U-value, the better the insulation. Thermally broken double glazing is around 40% more efficient than standard double glazing and miles better than single glazing.

Benefits of Thermally Broken Windows & Doors

Energy efficiency

Thermally broken windows and doors can improve your home’s energy efficiency by reducing heat loss and heat gain through the frames. When paired with high-performance glass, such as double glazing or low-e glass, your window and door systems are maximised for energy efficiency.

Australia’s National Construction Code has been progressively tightening energy efficiency requirements for new homes. The push toward a 7-star NatHERS rating for new builds means many Perth properties now need to meet lower whole-window U-values, often at or below 2.0 W/m²K. Thermally broken aluminium frames help achieve this.

Greater year-round comfort

Comfort is one of the most noticeable advantages of upgrading to thermally broken windows and doors.

Poorly insulated frames can create hot or cold spots near windows and doors. This can make rooms feel uncomfortable, even when the air conditioner or heater is running. Thermally broken frames help minimise this issue by reducing temperature transfer through the frame itself.

This means living areas, bedrooms, home offices and entertaining spaces can feel more consistent and comfortable throughout the day.

Long-term savings through reduced energy costs

Better insulation can reduce reliance on air conditioning and heating, lowering energy use over time. Windows can be one of the biggest sources of heat loss and gain in your home.  Almost 90% of unwanted heat enters a home through windows, and 40% of winter heat escapes through them. That’s a significant amount of energy your cooling and heating systems are working to compensate for, and that can really start to show on your electricity bill

Minimised condensation

Condensation can occur when warm indoor air meets a cold surface, such as a window frame or glass. Over time, condensation can contribute to moisture issues, mould growth, and damage around windows.

Thermally broken frames help reduce the likelihood of condensation forming on the interior surface of the frame because the inside of the frame is less affected by outdoor temperatures.

While ventilation, humidity and glass selection also play a role, thermally broken windows and doors can be an important part of managing condensation in the home.

Better acoustic performance

Thermally broken windows and doors can also help improve acoustic comfort, especially when combined with double glazing or suitable glass options.

The insulated frame design helps create a more effective barrier between the inside and outside of your home. This can help reduce the impact of traffic noise, nearby neighbours, schools, commercial areas or general street noise.

For homes on busy roads or in built-up areas, this added acoustic benefit can make indoor spaces feel quieter and more peaceful.

Why Thermally Broken Glass Matters for Perth’s Climate

Perth sits in Climate Zone 5: hot, dry summers and mild-to-cool winters. Our summer can get incredibly hot. Rooms near standard windows can feel noticeably hotter, even with air conditioning running. Thermally broken frames paired with Low-E glass (a type of glass with a coating that reflects radiant heat) can reduce that effect considerably, keeping rooms closer to a comfortable temperature without your cooling system working as hard.

For coastal suburbs like Cottesloe or Fremantle, there’s another advantage worth mentioning. The polyamide strip used in thermally broken frames is resistant to salt corrosion, making it a practical choice for homes exposed to sea air. Aluminium frames remain the preferred material over uPVC in these areas, and thermal break systems don’t compromise that.

Because our summers can be so intense, many Perth homes struggle in winter, as they are built to maximise airflow for summer rather than to retain heat. Homes lack adequate ceiling and wall insulation and can feature gaps around doors and windows, letting warm air out and cool air in. This means that while our winters are milder than most, they can still feel extremely chilly, particularly indoors.

This is where thermally broken windows and doors shine. The insulated barrier is designed to regulate temperature, keeping your house toasty in winter and gloriously cool in summer.

Is Thermally Broken Glass Worth It?

If you are weighing the options between standard frames and thermally broken frames, it often comes down to your local climate and budget. Thermally broken options are absolutely worth it if you want to better regulate your home’s temperature and noise levels, control condensation and save on energy bills.

Ready to find out what thermally broken windows and doors could do for your home? Perth Window & Door Replacement Company has supplied and installed quality windows and doors across Perth for over 40 years. Visit our Malaga Showroom to see the range in person, or get in touch for a free, no-obligation quote.

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