CONDENSATION

Condensation of water occurs on the inner surface of a window when the warm air inside the house, which contains water vapour, meets the cooler surface of the glass.

Air within a house contains a significant amount of amount of water as a result a evaporation from normal household activities, such as cooking, washing dishes and clothes, bathing and showering, etc. The warmer the temperature of air, the more water vapour it can carry. Eventually the warm air reaches a level where it is fully saturated with moisture; condensation will then occur as the air contacts a colder surface, lowering the air temperature, and tiny water droplets from on the surface. Generally the coldest surface in a house is the window, so must condensation appears on the inner glass surface.

Condensation can only be reduced by controlling the moisture level of the air, by the use of extractor fans above cookers and in bathroom ceilings which vent the damp air to the outside window-glass surface by the installation of insulate glass units. Insulated glass units are manufactured by permanently bonding two panes of glass with an edge spacer, sealing in a volume of dry air and creating an efficient insulator which provides a thermal barrier to the colder outside temperature; thus the inner pane stays warmer. It is important to understand that no solutions to reduce condensation can be effective unless the building structure is watertight and moisture from activities inside the home is minimised.

Insulated glass units offer further advantages in addition to condensation control, such as a reduction in noise penetration from the outside, and significant reductions in heating cost.