Condensation on windows is often indicative of air ventilation problems in a property that can lead to black mould growth and eventual damage to plaster, wallpaper, fixtures and fittings.

Condensation is visible on windows because glass is a non-absorbent surface, and while this may seem like an everyday and harmless problem nothing could be further from the truth. While condensation on windows is obvious, you are unlikely to notice condensation form on other surfaces such as walls and furniture where it is absorbed. It is on these absorbent surfaces that black mould is likely to grow.


If you are currently experiencing persistent problems with condensation on windows, here are a few simple solutions to help prevent condensation.

  • Opening the windows in your property for 5-10 minutes several times a day will release warm moist air from your property.
  • You should ensure that your windows trickle vents are kept open throughout the day.
  • Other air vents such as air bricks should be kept clear to allow airflow throughout your property.
  • When cooking ensure that extractor fans are turned on and pots and pans are covered so as little moisture as possible escapes. Air ventilation systems can be installed if you do not have an extractor fan.
  • When possible clothes should be dried outside and if you use a tumble dryer the warm air should be vented outside so that it does not form as condensation on windows.
  • After having a bath or shower try to open an outside window and close the bathroom door to allow the warm, moist air to escape.

The above DIY solutions are often enough to combat condensation problems on windows, but you may notice condensation becoming exacerbated if your windows are double glazed. If your condensation problems become more severe it may be worth considering professional condensation treatment


Condensation within double glazing typically suggests that there is a problem with the sealed unit of the windows. This means that a point in the edge seal of the window has failed and is allowing moisture to enter in the form of condensation. This form of moisture/condensation in double glazing is often the sign that the sealant between the glass and frame will have to be renewed.


You often see condensation in double glazed windows because the surface temperature of the window is cooler than the air inside the room. If the sealant around the double glazing has failed then the warm air is susceptible to entering the gap between the glass panes. When this warm air comes in contact with the cold air between the panes, it condenses. This is the same as condensation on windows without double glazing however, because in double glazing the windows are sealed so there is nowhere for the moisture to escape to.

If this is left untreated the condensation on the window can slide down the glass and onto the wall below. This can cause problems such as black mould or even the possibility of more serious problems such as wet rot or dry rot. Condensation in double glazing can also be unsightly as it will ‘fog’ the view out of the window.


Firstly, to help prevent condensation in double glazing, regularly check the seals around your windows to ensure there are no failures. To do this, you can check round the edge of the window for any gaps in the sealant by running a finger along it. If you feel any breakages in the sealant then it should be replaced.

Moreover, to minimise the occurrence of condensation appearing with the double glazing, it is advisable to help minimise the amount of moisture there may be within your property.  If there is excess moisture in the air it will condense onto cooler surfaces so you should attempt to remove this excess moisture. This can be done by ensuring that your home is well ventilated.


Find out why mechanical air ventilation is needed to combat the toughest condensation problems.


Don’t leave it too late. If you need condensation treatment, call Wise Property Care today or use our online contact form to let us know about your condensation problem.

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