What Causes Double Glazing Failure And How Can You Fix It?

Double glazing is one of the greatest innovations in the history of glasswork, allowing for long-lasting window panes that also improve security and keep homes warm.

Typically, a double-glazed window lasts decades, but there are certain signs and certain causes for it to fail.

Here are some common causes, how you can spot them and how you can fix them.



Misted double glazing, where condensation forms between the two panes of glass, is typically a major warning sign, but it is important to ensure that the misting is taking place within the glass.

Condensation, both inside and outside of the window is fairly normal, as it reflects the difference between the indoor and outdoor temperatures. If there is a lot of condensation, a dehumidifier can fix this issue.

However, if the condensation is between the two panes, this is often a sign that the window’s seal has been damaged, which can affect how effectively your window can keep the cold air out.

This can be as simple a fix as replacing the seal, but if the problem persists it can highlight an issue with the frame or even the window glass itself, both of which a professional can diagnose and fix.



One of the worst feelings on a chilly, windy night is to have all of the windows closed only for a rush of cold air to blow through the house.

Assuming there is no other cause, such as ventilation systems or an open door, it can mean an issue with the seal within a window. The best way to check is to feel around the window to see if you can feel the draught. If you can, it simply means the frame needs resealing.

However, if you feel a draught and cannot tell where it comes from it could be a sign that the glass or the frame has failed.


Minor Damage

Glass damage depends on the size and depth of the chip, crack or scratch. Most of the time, if they are not too deep, you can buff them out. However, a crack that is too deep can cause major issues and often means that the window itself needs to be replaced.