Is condensation a problem for you?

We’re all familiar with the phenomenon of condensation. Fogged windows in the bathroom after a shower or dew drops on the outside windows are just a couple of examples. Is it something to worry about, or does it just show you that have good insulation installed? The answer is nuanced, and we are happy to explain it to you.

Condensation occurs when warm, moist air becomes trapped and then comes into contact with a cold surface such as glass. This is something that can happen quite quickly, in a bathroom for example. A five minute shower is all it takes to achieve “steamy windows”. Fortunately, a little ventilation is usually sufficient to make the condensation disappear as quickly as it formed. If the condensation is persistent, it is best to look for the cause in order to solve the problem properly.


There are three types of condensation

  1. Condensation on the inside of the glass

Typical condensation on the inside of a window occurs when excess moisture cannot evaporate quickly enough due to a lack of fresh air flows. The warm and moist air then precipitates in the form of condensation on cold surfaces such as windows and mirrors. This is a common phenomenon in bedrooms, kitchens and bathrooms for example and is detrimental to the health and air quality of the indoor climate.

  1. Condensation on the outside of the glass

Condensation forming of the outside of glazing is usually due to a combination of a low outside temperature and high humidity, which is a typical phenomenon on a cold night with a clear sky. Because windows are usually well insulated, the temperature of the outer glass pane of double or triple glazing drops below the dew point temperature quite quickly, forming condensation. As soon as the temperature rises in the morning, the humidity decreases and the wind does its work to make the condensation rapidly disappear. In this case, condensation indicates good thermal insulation rather than suggesting there might be a problem.

  1. Condensation between the glass panels

Condensation between the glass panels of double or triple glazing indicates a serious problem and is either the result of a manufacturing defect or poor ventilation of the window profile. In both cases, it is best to contact the company that installed the glazing.


What are the potential consequences of condensation?

Condensation on the inside of your glass windows can have harmful consequences for your health and home in the long term if allowed to continue. A few examples:

  • Mould formation, the well-known poisonous black fungus that occurs in many damp areas.
  • Damage to wooden furniture and fittings such as stairs and doors.
  • Damage to interior walls, paint or wallpaper and the plaster.
  • Pests: Silverfish and dust mites love warm, moist places.
  • An unpleasant, musty smell.


How to prevent condensation?

Prevention is better than cure, and this applies to condensation as well. We would be happy to provide you with a few tips to prevent and/or solve condensation.

Condensation on the inside of the glass usually indicates an excess of warm, moist air in the home. This can usually be solved quite easily by:

  • Installation of an automatic decentralised ventilation system. Ensure the installation, and filters especially, are maintained regularly.
  • Crack open the windows during or after taking a shower or while cooking for extra ventilation.
  • Dry laundry outside when the weather permits.
  • Heat your house sufficiently.

To prevent condensation on the outside of the home, it is a good idea to clean the outside of the window with a water-repellent glass polish. This makes the windows smoother, giving water droplets less chance to stick. As an alternative solution, if the house location permits, open up the space around glass windows as much as possible for plenty of breeze.


For condensation between the glass parts of double or triple glazing, it is best to contact the company that installed the glazing. In this case, replacement of the glass is the only solution. We use an automated production process for our double and triple glazing, and we apply strict quality control to ensure the chance this type of condensation occurs in Group Ceyssens products is rather small. Should the problem nevertheless occur, do not hesitate to contact us. We will come and visit you on site and discuss how we can solve the problem.