If you are pricing a new build or a window replacement, you have probably been offered thermally broken aluminium windows as an upgrade, usually at a noticeable jump in cost. Most explanations of the technology come from cold-climate markets, which makes it hard to work out whether the upgrade earns its money in Perth. The honest answer depends on which way your glass faces, what you are trying to fix, and whether you have already spent on the right things. Here is how to tell.
Action Glass has been making and installing aluminium windows for Perth properties since 1969, so this is the conversation we have with homeowners and builders most weeks.
What a Thermal Break Window Actually Is
A thermal break window has an insulating barrier built into the middle of the frame, separating the outside face from the inside face. The barrier is usually a polyamide strip or a poured resin, and its job is to interrupt the path heat takes through the metal.
Without it, an aluminium frame is one continuous piece of metal running from the hot side of the wall to the cool side. With it, the frame becomes two pieces joined by something that conducts heat poorly. The window looks identical from the street.
Why Aluminium Window Frames Conduct Heat in the First Place
Aluminium is an excellent conductor. That is precisely why it is used for cookware, and it is the one genuine trade-off in a material that is otherwise ideal for Australian conditions. Standard aluminium window frames are strong enough to carry large panes on slim sightlines, they do not swell, warp or rot, and they handle coastal exposure and UV far better than timber.
The conductivity is a real weakness, but worth keeping in proportion. The frame is a minority of a window’s total area. The glass does most of the work, in both directions.
Are Thermally Broken Windows Worth It in Perth?
Perth’s problem is heat coming in, not heat escaping. That single fact reorders the priorities compared with the advice written for Melbourne, the UK or northern Europe.
Most unwanted summer heat arrives as radiation straight through the glass, not by conduction through the frame. So on a west-facing elevation taking the full afternoon sun, the first and biggest gains come from the glazing: a low solar heat gain coating, or double glazed units. Spending on a thermal break before addressing the glass is solving the smaller problem first.
Where thermally broken aluminium windows do earn their place:
- Large glazed areas. The more frame you have, the more the frame’s contribution matters. Big sliding and bifold openings shift the maths.
- High-performance and energy-rated builds. When a project has to hit a specific energy target, the frame is often what closes the last gap after the glass has done all it can.
- Air-conditioned homes running long hours. Reducing conducted heat lowers the load the system carries through summer.
- Condensation-prone rooms. Covered below, and frequently the reason people notice the difference day to day.
- Rooms where comfort near the window matters. A cooler frame in summer and a warmer one in winter changes how a space feels to sit in.
Where the case is weaker: a modest window replacement on a shaded or southern elevation, or any project where the existing glass is still single glazed. In those situations the money usually does more work elsewhere first.
The Condensation Benefit Nobody Mentions
Perth winter mornings are cool and damp, and plenty of homeowners wake to water sitting along the bottom of the frame. Condensation forms when a surface drops below the dew point of the air touching it, and a plain aluminium frame chills quickly overnight because it is connected directly to the outside.
A thermal break keeps the internal face of the frame closer to room temperature, so it is less likely to fall below the dew point. Over years, that matters for more than comfort: persistent moisture on sills damages paint, plasterboard and reveals, and it encourages mould in the corners. It is the improvement people tend to report first, and it rarely appears in the sales material.
Specifying Thermally Broken Aluminium Windows for a Perth Build
If you decide the upgrade is right, a few things are worth asking for before you sign.
Ask for the performance figures rather than the description. A window’s U-value describes how readily heat conducts through the whole assembly, and its solar heat gain coefficient describes how much sun energy it lets through. In Perth, the second number usually does more for comfort than the first, which is the reverse of the advice you will read from the northern hemisphere. Ask which specific frame system is being quoted, since thermal break designs vary and so does what they achieve.
Ask what the glass is doing too. The frame and the glazing work as one assembly, and a thermally broken frame around ordinary clear glass is an odd combination that rarely represents good value. The custom manufacture of your window frames should be specified as a system, not as a list of parts.
Finally, remember that all glass in windows and doors has to meet Australian Standard AS 1288, whatever the frame is made of. Energy performance is an addition to compliance, never a substitute for it.
Get Advice on Thermally Broken Aluminium Windows in Perth
The upgrade is genuinely worthwhile on the right project and genuinely wasted on the wrong one, and the difference is usually obvious once someone has looked at your orientation, your glazed area and what you are actually trying to fix. After more than 50 years of Perth installations, we would rather tell you where your money works hardest than sell you the most expensive option.
Contact Action Glass & Aluminium for a free quote and an honest assessment of whether thermally broken aluminium windows suit your property.
