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How does double glazing work?

How does double glazing work?



Double glazing is designed to improve your home's insulation but how does it actually work?

How does double glazing work? How does double-glazing work?

Since the 1980s, double glazing has become an essential requirement for millions of UK homeowners. Research suggests that less than 10% of UK properties haven't yet upgraded to double glazed windows and doors. If you're reading this article, it's highly likely that you're doing so in a building with double glazing. Walk down any street in the UK, and double glazing is everywhere. Whether your windows are made from uPVC, timber or aluminium, they're probably double glazed.

With double glazing such a ubiquitous part of our lives, you'd perhaps think that we'd all understand exactly how it works. As with many other modern mainstays, however, such as cars, computers, and even electricity, our technical understanding is often sadly lacking. In the 21st century, we take double glazing for granted. But if you've ever wondered how it works, read on to find out.

The construction of a double glazed window unit

A double glazed unit, often referred to as an IGU (insulated glass unit), consists of two glass panes attached together, with a seal between the outside edge of the glass and the window frame. The two glass panes are separated by a spacer also known as a warm edge which seals the gas or air between the two panes. The space between the two glass panes is often filled with an inert gas such as Argon because it is denser than air and improves thermal insulation.

Modern double glazed units, whether uPVC, aluminium or timber have a similar construction. Glass thickness can range from 3mm to 10mm and the window profile (the frame) is sometimes mass-produced by window fabricators but often bespoke designed because of the variety of window sizes requested.

Reducing heat loss with double glazing

Double glazing is designed to improve your home's insulation and energy efficiency. It helps to keep warm air inside your home and stops cold exterior air from entering your property. When the hot air molecules inside your home meet your double glazed window, they are transferred through the inner window pane. The Argon gas inside the IGU is a poor conductor of heat and slows down the heat escaping. The same happens with the cold exterior air. It is trapped by the IGU, preventing it from entering your home.

To minimise heat loss, the space between the two glass panes should be at least 12mm. Studies have shown that a small gap of this size is best for reducing heat loss by slowing down the transfer of molecules. It has also been suggested that installing modern glazing throughout your home can reduce heat loss by up to 64%. That's a massive reduction and will make a noticeable difference to your living environment.

Improving performance with modern technology

In recent years, modern advancements in technology have seen double glazing standards improve even further. Alongside Argon gas filled sealed units, several other scientific developments have enabled the glazing industry to meet increasingly strict regulations for thermal efficiency and security standards.

Low-E glass

Low-emissivity glass incorporates a specially designed Low-E coating to reduce infrared radiant energy emission. By doing this it can regulate the interior temperature and stop heat penetration from the sun while still allowing light to pass through the window. During its manufacture, an ultra-thin transparent coating is added to the glass. This thin coating is highly reflective and works for your home in a similar way to how a thermos keeps a drink at the same temperature.

Solar control glass

Solar control glass is manufactured by applying a tint or metallic coating to the surface of the glass. It is designed to reflect the sun's rays and can work in conjunction with Low-E glass to create solar control Low-E glass. Both solar control glass and Low-E glass help to reduce solar glare. With Low-E glass the coating is incorporated into the molten glass during production, while solar control coatings are applied to the surface of the glass, post-production.

Krypton and Xenon gas for double glazing panels

Most modern IGUs are filled with Argon gas to slow down heat loss. For certain, extremely thin, high-performance glazing units, Krypton gas is sometimes used. Krypton gas is even denser than Argon thus helping to further reduce heat loss. It is, however, far more expensive and along with Xenon is only used in extreme conditions for high specification projects.

Triple glazing

Triple glazing works in exactly the same way as double glazing but adds an extra pane of glass between the two existing panes. This creates a second gas-filled chamber to further increase the window's insulating capacity. Although still generally uncommon in the UK, triple glazing is a popular product throughout Scandinavia and is used in the UK to improve sound insulation in areas, for example, near airports, where exterior noise is a problem.

Benefits of double glazing

As you can see, double glazing can greatly improve the thermal performance of your home. In real terms, this means you'll have a warmer home and make potentially considerable savings on your heating bills while doing your bit to lower emissions and protect the environment. Installing modern double glazing can also help to:

  • Enhance the appearance of your home
  • Improve your home security
  • Create a quieter and calmer living environment
  • Add value to your property's market value
  • Reduce your home maintenance levels

At Everest, we take double glazing seriously. We only install the highest quality products and all our installation teams have a wealth of industry experience and all the required industry accreditations. We are so confident in the quality of our double glazing that we offer all our customers a range of guarantees to protect their investment. Alongside a comprehensive 10-year product guarantee, we offer a 30-year guarantee against rot and fungal attack and a lifetime guarantee against fog and condensation between the panes of our aluminium and uPVC windows.

If you'd like to find out more about our range of double glazing products then get in touch today. For more information or to get a free no-obligation quote call 0808 302 4726 or contact us online.


Book your free quotation appointment with one of our local expert consultants who will:

  • Provide an accurate, no-obligation quote
  • Offer ideas and practical solutions
  • Show you samples of our products
  • Take all necessary measurements


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