Households with condensation inside double glazing told 'there's only 1 fix'

It's something you will only notice at this time of year, as the temperature drops outside and your heating kicks in - but this common problem with double glazing windows can be an expensive, terminal issue.

During the colder months, heating, cooking, showers, boiling kettles and just generally existing inside your house will cause condensation to form on windows. That's fairly normal, and as long as you take steps to ventilate, such as opening windows, using an extractor fan or a dehumidifier, won't usually lead to mould and mildew.

But there's a more worrying problem when condensation forms in between the panes of glass on your windows. It's easy to test for this - just run your finger over the glass, and you'll realise the condensation fog is actually inside the window itself.

According to experts at EYG Windows, the main reason this happens is when the seal on the double glazing window fails, allowing moist air to enter and get trapped.

Unfortunately, there's no way to totally prevent this, and it's a fate which will ultimately befall any double glazed window eventually.

They said: "Eventually, the seal around the two panes which creates the 'sealed unit' will start to degrade and crack. This allows moist air (condensation) to get into the 'air gap' between the two panes of glass."

On more modern windows, there's still another cause: "Another reason why you may see condensation in double glazing is because of a fault with the 'spacer' bar. Most double-glazed windows now feature a 'spacer' in between the two panes of glass and this is full of desiccant, a highly-absorptive material which sucks up any moisture in the 'air gap' void.

"If there is even the slightest imperfection in the seal, this desiccant can quickly become saturated by any moist air or water which enters. When it cannot retain any more, the moisture then begins to appear as condensation."

As well as blocking your window visibility, a fogging up double glazed window is another worry - because it will cost you money on your heating bills.

They added: "The appearance of condensation in double glazing is both annoying and undesirable. Unfortunately, it also means that heat (which you're probably paying for) is escaping from your home.

"If you are experiencing condensation, moisture or large amounts of water between the two panes of glass it is likely the seal has completely failed. The likelihood is that the units have deteriorated past the point where they are no longer doing their job properly."

Unfortunately, there is only one way to fix it, and it's not guaranteed.

EYG adds: "If the uPVC units are in good condition, you may just be able to replace the sealed units. There are now a number of specialist companies which can repair or recondition each faulty unit.

"In most cases, the process involves drilling a hole into the 'spacer' bar or glass pane unit. A special drying agent or desiccant is then pumped or injected in to dry out the air or expel the condensation within the unit. An anti-fogging agent is sometimes used to prevent the build-up of any further moisture before the unit is completely sealed again.

"If you are considering a repair as opposed to a replacement, it is important to remember that the seal's failure is the most likely cause of the issue. Resealing will solve the problem, but may not actually address the core issue. Before undertaking a repair, think about whether the benefits and their expected life cycle will fully justify the expense involved."