How Long Do Double-Glazed Windows Last?

How Long Do Double-Glazed Windows Last?

Double glazing is a significant investment for any property. To understand how much of a return you’ll get on that investment, it’s only natural to ask how long double-glazed windows last.

If you’re spending thousands of pounds on something that lasts for decades, it’s fair to say you’ll be getting your money’s worth. On the flipside, if they need replacing in a few years, you might feel like the investment wasn’t worth it.

In this post, we’ll discuss how long double-glazed windows last, some of the problems that come with old double glazing and how you can extend the lifespan of your windows.

How long do double-glazed windows last

The lifespan of double glazing depends on a number of factors, not least the quality of the windows and how well they are installed. Cheap double glazing installed by a jack of all trades could need replacing within a matter of years, while premium products can last several decades.

However, broadly speaking, you can expect most double-glazed windows to last between 20-30 years. In many cases, you’ll get the reassurance of a warranty for the first 10 years or so, which provides added peace of mind – essentially guaranteeing that your windows will last at least a decade.

Using those estimates of how long double-glazed windows last, you can also get a rough idea of how much you’re paying for your windows per year. The average cost of double-glazed windows is between £3,000 to £7,000. If £5,000 windows last 30 years, it breaks down to less than £170 per year. However, if they only last 10 years, you will have essentially paid £500 for every year you had your double glazing.

Problems with old double-glazed windows

When you’re asking ‘how long do double-glazed windows last?’, it’s also worth considering what happens when they come to the end of their lifespan. While 20-30 years is a good rule of thumb, the longevity of windows depends on how well you want them to work.

As time passes, double-glazed windows can develop a number of problems, including:

Draughts and poor thermal efficiency

If the seals around your windows break down, you might notice a cold draught coming in. You can test this by holding a lit match or candle around the window and checking if the flame moves. Unfortunately, cold air coming in also means heat is getting out. Inefficient windows could make it harder to keep your home’s temperature comfortable, with rising energy bills to boot.

Condensation on the inside of windows

Windows that aren’t thermally efficient will usually get cold on the inside, which can attract moisture to settle as condensation. This is a common problem for single-glazed windows, but can also affect double-glazed windows if they’re old and inefficient. That’s especially true if your home isn’t well ventilated and there’s a lot of moisture in the air.

Condensation between the panes

Broken seals around your windowpanes could also allow moisture inside the unit, which then becomes trapped. You’ll notice this when the windows get misty, or even visibly wet, on the inside. This can be even more frustrating than the previous problem, as you can’t access the condensation to wipe it away.

Water ingress

It’s not just the cold temperatures that windows have to keep out. Years of battering from rain, wind and snow can eventually take its toll, with some of that weather getting through small gaps around your windows.

Difficulty opening and closing

Of course, another sign of ageing for windows is when they become difficult to open and close. This could simply be down to wear and tear, with handles, locks and other parts breaking. Or there might be something causing your windows to jam, such as paint or dirt and debris.

How this all affects your windows’ lifespan

If you’re not bothered by windows that are misty, draughty and worn, you could keep your windows well beyond their typical lifespan. However, most people will see these issues as signs that their windows need to be repaired or replaced.

Making double-glazed windows last longer

There are a number of steps you can take to make your double glazing last longer. First and foremost, invest in quality when you have them installed. The saying goes – buy cheap, buy twice. By buying top-quality double glazing and having it installed by a professional, well-rated company, you’ll get more out of your windows in the long run.

You can also perform some small maintenance jobs to keep your windows working well through the years. Silicone caulk can be used to fill gaps around the window unit, for instance, eliminating draughts and water ingress. Cleaning your window frames regularly and spraying with lubricant can also minimise the risk of them jamming further down the line.

As for condensation, some companies offer a restoration service where a small hole is drilled to remove moisture from inside the pane, before resealing the unit. Unfortunately, it’s not the most effective solution. The same is true for draught-proofing strips that aim to improve double-glazed windows’ heat retention.

Can secondary glazing help?

If you’re concerned about how long double-glazed windows last, and think your windows are coming to the end of their lifespan, secondary glazing could help. Installing a high-performing secondary panel on the inside of your windows can eliminate many of the issues that come with old double glazing.

With a fully sealed panel and a slightly larger gap of air than double glazing, secondary glazing can vastly improve heat retention to keep your home comfortable (and your bills low) all year round.

Secondary glazing can also minimise condensation on double-glazed windows by sealing them off from your home, as well as eliminating the cold interior surface which attracts condensation to your existing windows.

That’s paired with better security and noise reduction, all without affecting your existing windows or impacting the look of your home.

Get a secondary glazing quote

Want to give your double-glazed windows a new lease of life? At Clearview, we provide made-to-measure secondary glazing for windows of all shapes and sizes, complete with a 10-year guarantee.

Choose from top-quality DIY kits or professional installation, then enjoy thermally-efficient, mist-free windows for years to come. Get a free, no obligation quote today to get the ball rolling.


Clearview secondary glazing - the solution to significantly improved acoustic and heat insulation to your property, making your home or offices more comfortable, secure, greener and cost efficient to run. Achieved without the disruption of replacement windows, and without damaging the character of your building.

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