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What is Double Glazing?

Category: Blog, Tips and Tutorials

Double glazing cutaway section

Double Glazed Windows are windows that contain two panels of glass separated by air or a non-toxic gas called Argon. 

This gap between the glass panels can potentially have a significant impact on heat transfer from the outside of your home to the inside, and vice versa. And depending on the glass combinations being used with your Double Glazing, it can also have an impact on noise reduction inside and outside your home.

Now that we’ve covered the basics, let’s take a moment to consider how Double Glazed Windows might suit your home and your budget.

Double Glazing Diagram

Why Choose Double Glazed Windows?

Double Glazed Windows offer three benefits that distinguish it from your typical glass window. These are:

  1. Noise reduction
  2. Thermal comfort; and
  3. Energy efficiency

Noise Reduction

Noisy neighbourhoods can be an issue. Fortunately, with the right combination of glass options, Double Glazing helps limit these noisy interruptions by absorbing soundwaves to give you a quieter, more comfortable home. Double Glazing also works when the circumstances have been reversed—on movie night, for instance. With Double Glazing you can turn the volume up and still be a considerate neighbour.

Thermal Comfort

It is estimated that 40% of a home’s heating energy can be lost, and 87% of its heat can be gained through its windows. (https://www.yourhome.gov.au/passive-design/glazing). With Double Glazing, heat regulation becomes easier and more stable.

Energy Efficiency

Due to the temperature regulation that Double Glazing provides, you don’t have to use as much power to beat the heat or stay warm. And by using less heating and cooling in your home you can save money on your energy bill. Win, win!


  • Double Glazed windows work by creating a sealed air or gas vacuum between the two panels of glass
  • The space between both panes of glass has an optimal distance to maximise performance and can have a significant effect on heat transfer both into and out of your home
  • The vacuum also assists in the absorption of soundwaves as only a percentage of the sound vibration on the outer glass pane is transferred on to the internal glass pane, thus reducing what can be heard inside
  • Jason Windows uses Argon gas because it is more effective than air when preventing heat transfer due to its increased density and reduced thermal conductivity

Secondary Glazing is not the same as Double Glazing

  • Secondary Glazing is the use of an acrylic panel placed on the inside of an existing window to simulate the effects of Double Glazing.
  • Secondary glazing has been known to be potentially as effective in noise reduction, but less effective in thermal comfort and energy efficiency.
  • Without the need to replace your window frames, secondary glazing can be a cheaper alternative to Double Glazing. It’s one of the many budgeting decisions you’ll make when planning your new home or renovation, just like choosing between a stone benchtop or the more affordable laminate benchtop.

You may also come across the term “Retrofit Double Glazing” when researching Double Glazing options for your home. This term refers to being able to fit Double Glazed windows to your existing window frames rather than having to install new ones. If you are considering this as an option, be sure to clarify with your contractor that it is bona fide Double Glazing as some contractors use the terms ‘secondary glazing’ and ‘double glazing’ interchangeably.

Are Double Glazed Windows the right choice for you?

The suitability of Double Glazing depends on your home orientation, design, budget, and overall needs.

To learn more about other solutions, have a look through the Jason Windows Glass Guide to find out more about our Double Glazing and other glass options!


About the Author

Peter denBoer, President – Glass and Window Association of WA

Peter den Boer has worked in the Australian Glass Industry for over 38 years and is well respected for his experience and knowledge within the industry.
Peter has been the past President of the Glass and Window Association of WA since 2014 before being merged in 2018 and had been a board member of the Australian Glass & Glazing Association since 2015. Now a board member of the merged entity – Australian Glass and Window Association.



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