Why do double glazed windows fog up on the outside

Why do double glazed windows fog up on the outside – all about condensation in double glazing

Double glazed or triple glazed windows are known for their high level of thermal efficiency. Hence, many homeowners and property owners are taken aback when they see condensation forming on the outside of their double glazed windows.

Condensation on the inside of double glazed windows is a common phenomenon many homeowners are aware of. But fogging on the outside of these windows is something that confuses most of them.

Moreover, condensation on the outside is visually unappealing. It kind of ruins the look of your new home. That’s why it is natural most property owners are concerned about their double-glazed and triple glazed windows fogging on the outside.

Hello there! If you are a homeowner in Australia who has recently gotten thermally broken double glazed windows installed on your property and are concerned about the formation of condensation on the outside, worry now. We are here to help! In this post, we will tell you all about the reasons double glazed windows fog up on the outside. We will also explain in detail the difference between fogging that happens on the inside of the double glazed windows, in between the glazes, and fogging on the outside of the windows.

Also, if you are a homeowner in Australia looking to install energy efficient double glazed windows in your property, we manufacture and supply custom-made windows and doors with double glazing. All our double glazed windows come with Low E-glass and Argon Gas for superior thermal efficiency.

We are a formidable amalgamation of exceptional customer service and expert craftsmanship, thus ensuring that your newly installed double glazed windows will be of top-notch quality and performance.

Why does condensation form on the outside of double-glazed windows?

Condensation on the outside of double glazing happens simply because the outside temperature is warmer than the temperature of the glass surface.

Condensation is the process through which a gas turns into a liquid. The phenomenon of condensation occurs when water vapor in the air comes into contact with a surface colder than it is. To be more precise, if the temperature of that surface falls below what is called the dew point temperature, water vapor from the air will begin to accumulate on the surface of that object.

That is precisely why water condenses on the outside surface of glass in double glazed windows. The temperature of that glass has dropped below the dew point temperature of the external air.

The newly installed double glazing and triple glazing units have inner panes constituted of low emissivity glass. This enhances the thermal efficiency of the double glazed windows and thus prevents the movement of heat across the glazing unit, resulting in the outer surface of the windows getting colder.

Whether you have opted for thermally broken aluminum windows, solid profiles of natural wood, or multi-chamber PVCu windows, your glass is still coming into contact with the air outside, thus resulting in the outside of your windows fogging up.

Is condensation on the exterior surface of double glazed windows harmful?

This is why many homeowners are concerned about condensation on the exterior of windows with double glazing. They think fogging on the outside of their double glazed windows could indicate some sort of blockage or inefficiency in the working of their windows.

On the contrary, the condensation forming outside the double glazing of your windows indicates that your windows are working rather well and are at the peak of their efficiency!

The low emissivity glass that is used to design inner panes for new double or triple glazed units in windows is designed specifically to stop the heat transfer across the glazing unit, thus ensuring that the outer glass pane of your double glazed windows never gets warm.

In fact, the better the thermal insulation provided by your double glazing, the lower the temperature of the exterior window frame, thus resulting in the formation of condensation on the outside of your double glazed windows.

In a nutshell, condensation formation on the exterior surface of your double glazed windows isn’t a cause of concern. It rather tells you that your thermally broken energy-efficient windows are working exactly as they should.

Why do windows and doors with double glazing fog up on the inside

Fogging on the inside of double or triple glazed windows is also quite common and not usually a cause of concern.

Condensation on the inside of double glazed windows is caused by humidity in the air inside your home and excessive moisture buildup. Indoor air can have a lot of moisture depending on the way our houses are designed. Excessive moisture from cooking, heating, shower cubicles, etc. can cause condensation inside your home and thus lead to the formation of mist on the surface of your window glass.

Condensation on the inside of a window with double glazing isn’t something to worry about. A bit of moisture at home is normal. You cannot altogether eliminate moisture, no matter how hard you try.

You can ventilate your rooms as much as possible to prevent the excessive buildup of moisture. You should pay special attention to ventilating spaces prone to excessive moisture such as bathrooms and kitchens. Also, consider getting your windows fitted with triple ventilators. These compact and discreet ventilators in windows and doors are highly effective.

Check out our article on How To Clear Misted Double Glazed Windows and How To Adjust Double-Glazed Windows.

Fogging between the panes of glass in windows with double glazing

Fogging between the two glass panes on the inside of the sealed unit with double glazing indicates that your double glazed unit needs urgent replacement.

It usually indicates that the hermetic seal keeping the glass unit together has failed. Thus, your windows are no longer energy efficient as excessive amounts of moisture and air can enter through the gaps in between your double-glazed units.

What can I do about fogging on the outside of a window with double glazing?

You cannot altogether stop condensation formation on the outside of a window with double glazing. But you can certainly try out a few things to minimize the fogging.

  • You can regularly wipe off the accumulated moisture on the outside of your double glazed windows. While it’s not a practical long-term measure, it certainly helps in day-to-day maintenance.
  • You could also opt for self-cleaning glass. It’s a special type of glass with a unique hydrophilic and photocatalytic coating on one face. The coating that gets activated through exposure to UV rays of the sun, breaks down organic dirt that lands on its surface and also prevents inorganic dirt from sticking onto the surface.
  • If you have an outdoor garden, consider creating a clear demarcated area between your windows and your garden plants. This would ensure better circulation of air around the outside of your double glazed windows.

Wrapping Up

Condensation formation on the outside of your energy-efficient windows with double glazing isn’t  a cause of concern. It’s quite usual to see this phenomenon in brand-new windows so you mustn’t worry too much about it.

However, you must be very careful while choosing double glazed windows for your home or commercial property in Australia. You must always opt for windows with low E-glass that are specially designed to ensure optimal energy efficiency, thus keeping your energy bills reasonably low during both winters and summers.

Thermally efficient windows with double glazing can bring down your electricity bills by as much as 40 percent! They are sleek, modern, stylish, and durable, thus significantly reducing long- term maintenance costs.

However, when choosing double glazed windows for your home, it’s important to choose the right service provider who has enormous expertise in the area and hands-on experience with local conditions to ensure the delivery and installation of genuine and top-notch double glazed windows.


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