Double glazed units & Condensation in windows
What is a double glazed unit?
Double glazed units can be found within UPVC, timber or aluminium window frames or doors. They comprise of two single panes of glass and a spacer bar in between. Contained within the spacer bar are tiny silica balls made from either silica gel or calcium chloride (also known as desiccant). The edge of the panes are sealed creating an insulating void between them, this gap being in the form of a vacuum or it can also be filled with a gas.
Condensation Condensation can appear on double glazed units externally (outside property facing & inside property facing) and internally (within the two panes of glass). Condensation externally (outside property facing) is a natural occurrence and doesn’t indicate a fault with a double glazed unit. This happens mainly in spring and autumn when the glass temperature drops to a low level during the night and the moisture of morning dew condenses against the cold surface of the glass.
Condensation externally (inside property facing) can occur for several reasons. If the temperature in a property or room is low it creates a cold surface that warm air can condense onto. If there is a lack of air circulation within an area then the moisture in the air won’t clear and will again condensate on the windows. Lastly another reason is if there is too much humidity in a room or property. Condensation in windows Commonly termed as a ‘blown seal’ or ‘broken seal’, a faulty seal is the main cause of condensation in windows which allows moist air into the void. Faulty seals can occur for several reasons. The main reason being general wear and tear and age. Continuous changes in temperature can also cause fluctuations in the size of the glazed unit, as they expand in warmth and contract in the cold, and over time this can loosen and damage the seals. Other reasons associated with the seal include faulty installation, faulty production methods and strong cleaning products being used to clean the glass eating away at the seal if chemically abrasive.
There are quick fixes on the market to rectify condensation in windows but in order to make your windows energy efficient again then they will need replacing. There are some companies out there who will say you need new windows. This is not necessary unless there are insulation issues within the frame. If you have condensation in your windows then contact Selkent Glazing & Locks for a survey today.
Image of double glazed unit information courtesy of home windows