We often get asked about external condensation as there is a common misconception that it is caused through a fault in glazing units. Condensation, a natural occurrence, can occur on the external surface of double glazed units, especially as winter approaches. To help explain, we investigate the causes below.
What Causes External Condensation?
Condensation is caused when the outside temperature of glass is lower than the temperature inside. Cold nights and dropping temperatures result in the formation of water vapour on the external outer panes of windows.
Moisture condenses out of the air onto a cold surface at what is known as
dew point. The dew point temperature is the temperature at which the air can no longer "hold" all of the
water vapour which is mixed with it. Some of the water vapour at this point must therefore
condense into liquid water.
Typically in the spring and autumn months the dew point can be comparatively higher, causing condensation to occur more regularly.
Condensation and Modern Glazing
Condensation on the external surface is becoming more common as the types of
glazing units being fitted into homes today are much more thermally efficient than in the past. The more thermally insulating the
glass is, the lower the outer pane temperature is likely to be and the greater chance condensation will occur on external surfaces. With traditional style
single glazing and older style
double glazing, a large proportion of heat was lost to the outside through the
glass.
There is not much that can be done to prevent external condensation. A plus point is the knowledge that the glass is keeping the heat in as it is designed to do, demonstrating that you have a highly thermally insulating product. In many cases the condensation does not last long, as a little heat from the sun will warm the outer pane of the
glass enough to allow the water to evaporate. However one of the major benefits of energy efficient double and triple glazing is the reduction or in most cases the total removal of internal condensation when compared to single glazing.
Pilkington Activ™
Those people who have fitted Pilkington
Activ™ self-cleaning
glass may also notice that they get fewer occurrences. Pilkington
Activ™ is best suited to tackle condensation, with its properties that allow beads of water to form on the surface of the
glass, and run simply off.
For information on Pilkington
Activ™ and its self-cleaning properties please visit our
official website or
click here.