How Long Does Double Glazing Last?

Giving a definitive answer on how long a double-glazing installation will last is tricky because of how specific each installation is. A lot of things can affect how long double glazing remains effective from the initial quality of the build, the punishment the home receives from the weather, how well-maintained the installation is and much more.

What is the average lifespan of double glazing?

The lifespan of your windows is completely reliant on the external and environmental factors that surround them. However, there are key signs that your windows aren’t holding out as well as they should be and similarly, there are ways that you can make sure your windows last as long as possible.

The average timespan for a double glazing window is 20 years minimum, but they have the potential to reach as high as 50 years.

When double glazing was first introduced back in the 1950s in the United States, the trend caught on quickly because of the many benefits double glazing provides for the home, including increased thermal efficiency, enhanced security and exceptional noise reduction. By the 1980s, the single glazing installed after WW2 in the UK needed replacing, and double glazing came to fill the void.

That double glazing installed back then is now reaching the end of its lifespan (if it hasn’t already), and such, we’re seeing a lot of homeowners having their installations replaced with new frames and fresh panes of glass.

What causes double glazing to deteriorate?

Over time, it is expected that wear and tear will affect double glazing units just as it will affect any other part of the home. Small damages around the seals can especially cause the insulating gas between the panes to start to leak out. The Centre for Sustainable Energy suggests that when roughly 25% of the gas has leaked out, the window’s thermal performance begins to suffer. At this point, it is worth considering replacing the windows with new installations.

Once leaks start to appear, you are also at greater risk of condensation appearing on the inside of the window. This is a real concern and is a clear sign that the window is no longer working effectively and either needs replacing or repairing. Condensation will start to appear on the inside as the insulating gas leaks out, and warm air from outside the window moves in to replace it. The warm air will then condense on the inside because of how cold the outer pane will get and the risks of causing further damage to the rest of the installation.

Many things can cause double glazing to deteriorate. However, the most common cause of degradation is extreme weather conditions. The difference in temperature between the outer pane and the inner pane causes strain on the IGU (insulating glass unit), and the closer they are together, the more likely the window is going to struggle. For homes that deal with extreme weather conditions regularly, one of the ways you can assure that your installations last is to ask to have the internal gap be larger than average. The temperature difference isn’t as effective at degrading the window with a larger internal gap.


Top-quality double glazing installations should last at least 20 years. Considerations need to be made for weather conditions and temperature fluctuations in the area you’re living in because these are the external factors that will affect your window the most. Any good quality installer will be aware of the conditions that surround your property and will be able to recommend the proper specifications that should keep your double glazing installations in working condition for as long as possible.

Here at Double Glazing on the Web, we want to share our expertise with our customers and clients. It makes a huge difference if you’re aware of what you’re buying to ensure you get a quality build and a worthwhile investment.

If you’re interested in getting a quote from us in order to start comparing the various double glazing installers in the industry, then please feel free to use our quick and easy online pricing tool. You can also contact us directly through our online contact form if you have any specific questions.

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