Condensation on windows is a problem for many homeowners, and it can occur in all types of buildings. Singled-glazed windows are a primary cause of condensation, though many modern day double-glazed windows do condensate. This is usually due to poor manufacturing and inadequate installation.

The damage condensation can cause:

These modern insulating measures have created rooms with much less ventilation. A good example of this is many homes have had traditional fire places removed or been blocked up. The result is that the water vapour produced by normal living activities is no longer able to escape up the chimney or through doors, window joints and other outlets.

How to stop condensation without compromising on insulation and comfort?

There are a few temporary fixes to condensation on windows, which range from daily wiping with towels to installing costly Dehumidifiers. However these present an ongoing issue and do not completely eradicate the problem.

The only way to truly and permanently stop condensation on windows is to replace the single-glazed windows with double-glazed units. And to follow a few simple tips in conjunction with heating and controlled ventilation.

Click here to find out more about our double-glazing sash window system, which is specially designed for existing single-glazed sash and other original period windows and doors.

How is condensation formed?

Simply put, the air that surrounds our homes holds water vapour, when warm air meets cold windows, you get condensation. The sudden drop in temperature causes the water vapour in the air to turn back into water, first creating a mist over your windows. Then eventually turning into water drops. Think of it as the reverse of a kettle boiling.

A good example of this is when you breath onto a mirror. Condensation occurs because the exhaled air is saturated and its temperature is higher than that of the mirror (which is at room temperature).

There are three main elements governing condensation, the first two are normally controllable.

  1. Water vapour content of the air:-This is produced by normal living activities such as washing, cooking, bathing etc, and can be controlled by the use of extractor fans, cowling, and ventilation in appropriate places.
  2. Inside room temperature:- This can be controlled by replacing single glazing with double glazing, thereby maintaining a higher surface temperature of the glass on the room side, and by increasing the air temperature to enable it to hold more water vapour without condensing.
  3. Outside temperature:-This cannot be controlled, but it can be countered when it falls by increasing the indoor heating.

How does double glazing reduce condensation?

Double glazing is an insulator, designed to reduce the loss of heat by conduction from the inside to the outside of a building. Under average exposure conditions, and provided the room is heated, the room side surface temperature of the inner glass will be greater than the outside external glass. The likelihood of condensation occurring when warm moist air in the room comes into contact with the surface of the glass is dramatically reduced.

What if condensation forms on double glazing?

As double glazing is an insulator and not a source of heat; nor does it control the amount of water vapour in the air. If a room is inadequately heated and there is no heat to retain, double-glazing cannot full fill the purpose for which it was installed. Thou the condensation on single-glazing would be dramatically more, if the outside and inside temperature where the same.

Double-glazing cannot cause condensation. By acting as a heat barrier and providing an inner pane which is considerably warmer than the outer pane, condensation is reduced.

There are two main factors for why condensation forms on double-glazing:-
  1. Condensation on the inner glass:- This means that the temperature of the room side glass surface is too low given the water vapour content of the atmosphere in the room.
  2. Condensation within the cavity:- This means the sealed unit has failed and inert gases have leaked. A simple way to test this is to wipe the glass, if you cannot remove the moisture then the unit has failed.

With any type of double-glazing you have to keep the internal temperature of the room higher than the external. Controlling any added moisture created by everyday household objects.I.e Fit hoods over cookers and other equipment producing steam, and ventilate them to the outside air. If you follow these simple steps then condensation will not occur.

Come to our show room at the Glass works, Skeoge industrial estate Derry City Northern Ireland and have a look at these in person or contact us today on 02871 357 444.