Does Double Glazing Keep Heat out in Perth, Australia?

Energy-efficient buildings are great at helping you keep your costs low. The logic this follows is very straightforward. If there’s heat in the home, then your cooling system has less work to do, meaning your energy bills will remain low.

Additionally, assuming there is a low radiant heat flow, maintaining that cooler temperature should be no challenge for your air conditioning unit.

Equipping your home for better thermal performance can be done in numerous ways. Thanks to double glazing for windows and doors, glass panes can become a part of your energy efficiency strategy.

The idea here is to explore what it is about double-glazed windows that help them to keep unwanted heat out of your home.

The Difference Between Single-pane Glass Windows and Double or Triple Glazing?

Before going on to understand the heat gain or heat loss dynamics that double glazing brings to the table, it’s probably a good idea to gain an understanding of the different glazing types that could form a part of your window system.

First, there are single-pane glass windows (single-glazed windows). As the name implies, it’s one pane of glass. They aren’t energy-efficient designs. However, some people may use low emissivity (low-e) glass to gain some measure of better performance.

Double glazing and triple glazing combine multiple glass layers. Therefore, they are often called insulated glass units or IGUs. There’s a gap between each layer, which uses air, which is a bad heat conductor, to improve thermal performance.

What Determines the Performance of Double or Triple-glazed Units?

Not every double glazing setup in a window frame is built equal. How energy efficient the composition is will depend on a couple of factors:

  • Whether the empty cavity is filled with air or a gas that conducts even less heat such as argon
  • The spacer’s (a metal or polymer strip used to separate the layers) ability to absorb moisture
  • How wide the empty cavity is
  • The sealing of the cavity
  • What properties are present in each of the glass layers

How Do Double-glazed Windows Affect Bills Based on Heat Energy?

Put simply, double-glazed windows prevent the transference of heat from one side of the window to the other. Depending on the conditions, this will be favourable based on a lack of heat loss or heat gain.

During hot periods, this translates to the heat that’s outside remaining out there.

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Does the Window Type Have an Impact on Energy Efficiency?

While double-glazing windows and doors will most certainly increase energy efficiency, you can compound the effectiveness of doing so by implementing certain kinds of glass.

Low Emissivity Glass

The low-e glass comes in two forms. The first is high transmission, which allows the passage of daylight while reducing the escape of long-wavelength infrared heat. There’s also the low transmission variation that reduces solar heat gain while preserving light transmission.

Laminated Glass

You tend to find this in rooms that are most likely to cause a human injury from impact. Typically, you’ll find that glass breaks into shards and shard slivers that can cause mild to severe harm.

While the danger isn’t eliminated, the use of laminated glass reduces the risk thanks to its plastic glazing layer, which sits between two sheets of standard glass. Should there be a break, the adhesive nature of the layer will hold the shards in place, to minimize the level of danger.

Toughened Glass

A reheating and cooling process called tempering is responsible for this glass’ reputation of hardness. You’ll find it to be a lot stronger than your standard glass. This doesn’t mean it will not break. However, the pressure required to cause a break is much greater.

A bonus is that when a break does happen, there’s less dangerous than usual because it shatters into cubic-shaped pieces.

Toned Glass

During the manufacturing process, this kind of glass is infused with colouring additives. You will usually see it sporting a green, blue, bronze, or grey hue. Note that the colour differences have more than just a visual significance. Depending on the colour you choose, the amount of visible light transmitted will vary.

There is a super-toned variation that takes advantage of heavier colouration than its standard counterpart. It’s great for lowering the amount of solar heat gain without impacting the light levels present.

Important Concepts to Understand


Solar Heat Gain

The term “solar gain” has been thrown around a couple of times, and it’s good to understand what it means and how it fits in.

It’s a measure of the extent to which the direct sunlight’s heat will flow throw the entire window (this means both the frame and the glass). As you contemplate double-glazed windows and doors, it’s always good to understand how each material stacks up.

You’ll find the measurement is expressed as a solar heat gain coefficient (SHGC). However, it’s expressed as SHGCw for windows. When considering double glazing, it’s good to pay attention to the SHGC that manufacturers declare.

Window Energy Rating Scheme (WERS)

If you check the Australian Window Association page, you will see this term almost immediately. What does it have to do with double glazing, though?

Put simply, WERS gives you a measure of energy-related performance. While the focus here may be on single or double-glazed windows, the metric also applies to skylights and doors.

Several details go into the complete measure including the SHGC and U value (how well the complete window conducts heat). Visible light transmission and air infiltration details are also a part of the metric.

Your double glazing specialist will refer to the performance regulations for your location before getting the project started.

Other Benefits That a Double-glazed Window May Offer

If you’re thinking about double glazing, you already know that you have a lot to gain where maintaining a consistent internal temperature is concerned. What other benefits are there, though?

UV Damage Protection

Seeing the sunlight shining in often gives off a wonderful feeling, but what if it was causing more damage than you realize? Have you ever noticed that your photos near windows are faded, for example?

That’s because the intense rays are harmful to some materials you may have inside. Double-glazed windows offer a great measure of protection in this regard.

Noise Cancellation

People often think of insulation as only a temperature-based thing. However, there is an audio element to it as well. While double glazing is not going to give the same effect as soundproofing a space, it is essential in mitigating a lot of the extra noise. Who knows? It could be the difference between an event keeping you up at night or not.


Typically, double glazing means smashing the glass is more difficult than usual, especially if one of the harder variations is used. Additionally, these windows tend to be configured for closure from the inside, which is another deterrent to burglary.

The Bottom Line

If you want to prevent your home from becoming an oven when the outside gets hot, double glazing makes for a great alternative to the single pane configuration of traditional windows, even if secondary glazing is applied to them.

Upgrade your existing windows today with a premier manufacturer and installer of double-glazed windows and doors in your corner. Let Thermaglaze guide you! Call us today at 1300 022 867 or visit our contact page to book a free measure and quote!

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