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Double Glazing Condensation: How to fix it

Double Glazing Condensation: How to fix it

Double glazed windows have been used for many years as a cost effective way of insulating buildings and increasing energy efficiency and security. But we all know too well the annoying sight of water droplets and condensation building up between the panes of glass and how impossible it feels to get rid of.

Why does condensation form in double glazed windows?

Condensation is the result of a difference in temperature between the outside – which is usually colder – and the inside – which is warmer – surfaces of the glazed window. Condensation occurs when vapour is cooled to a certain temperature – resulting in water droplets appearing.

Double glazing units are typically made by two panes of glass being separated by a metal or plastic space forming a gap in which gas can be used or a vacuum created for insulation. The cavities between the panes of glass are usually sealed to the window frame using a rubber seal which prevents air escaping. However, over time the seal can fail, compromising the cavity and allowing warm air between the panes – resulting in condensation

Thanks to the wet winters and humid summers we experience in the UK – condensation is a common occurrence in our homes.

So how do we fix the problem of condensation in double glazed windows?

Condensation forming between the panes of double-glazed windows nearly always means that the seal has failed and unfortunately, the fixes for this are rather laborious and expensive:

 

Replacing the faulty units with new

If you’re lucky, and only experiencing condensation forming in a few of your windows, then you’ll be able to get away with replacing just those units – which is significantly cheaper than replacing all of them.

Choose a reputable window installation company, or your original installers, and you will likely get a guarantee that your units will last a certain number of years.

The benefit of going down this route is that you may have the option to upgrade your units, making your house or building more energy efficient and seeing some return on what you spend.

condensation on double glazed windows

Replacing or repairing the faulty seals

This is becoming a much more common solution as more and more companies begin to offer it.

There are several ways to approach repairing faulty seals but most commonly one or two holes are drilled in one of the panes of glass or spacing bars. A drying agent is then pumped into the unit along with an anti-fogging agent to prevent future build-up of moisture.

Replacing the seal completely usually involves injecting a sealant material into the unit along the original seals to prevent air getting in and further moisture appearing.

If you go down this route again – go for a reputable company that can offer good testimonials and a guarantee for their work.

 

Preventing Condensation Forming

One of the best ways to fix condensation in your double glazing is to prevent it forming in the first place.

Regularly check the seals around your window units and check for any damage or failures. Keeping them clean by using a mild cleaning agent will help them last longer.

Reducing the moisture within your home will also help your window seals maintain their integrity, and prevent condensation forming on the interior face of your windows. Moisture inside your home can be reduced by:

  • Installing an extractor fan above your hob and keep pans covered with lids when cooking
  • If your bathroom is prone to damp, consider installing an extractor fan for use during bathing or showering
  • If installing an extractor fan or hood isn’t an option, keep a window open to clear the humidity when using the bathroom or kitchen
  • Whenever possible, dry clothes outside or on a clothes horse – drying clothes on radiators will create more moisture
  • If you have a tumble dryer – direct the vent pipe out of a window away from the inside of your house
  • When condensation does form wipe it off thoroughly
  • Whenever you can – ventilate your house by opening windows and allowing fresh air to circulate round your house.

 

If these steps are not useful feel free to check out this video which shows another technique you can use to remove condensation from double glazed windows.


Double glazing condensation is not only a nuisance but can result in costly wasted energy due to failed sealants and even health issues where mould is forming. Whilst prevention is cheaper than a cure – in the event of repairs or replacements being needed always go for a reputable company who guarantee their work.

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