Why Does Double Glazing Mist Up and Show Condensation Between the Glass?

Double glazing is designed to keep your home warmer, more comfortable and your windows clear. But over time, double glazed sealed units can deteriorate and lose their airtight seal. When this happens, moisture can enter the space between the two panes of glass, causing condensation, misting and a cloudy appearance inside the sealed unit.

This is different from condensation on the inside or outside surface of your window. If you can see moisture trapped between the panes of glass, it is a common sign that the double glazed sealed unit has failed. As the seal breaks down, the misting can become increasingly noticeable, obscuring your view and making your windows look permanently cloudy – even on a very bright, sunny day when you would expect the glass to be clear.

Can Failed Double Glazing Affect Your View?

Yes. As moisture and misting build up between the panes, the glass can develop a hazy or cloudy appearance that affects the clarity of the view through your windows. Bright sunlight can make the problem particularly obvious, highlighting the condensation trapped inside the sealed unit.

Does Misted Double Glazing Mean the Sealed Unit Has Failed?

In many cases, yes. Condensation between the panes of double glazing indicates that the insulating seal around the sealed unit may have failed, allowing moisture into the cavity. This does not necessarily mean the entire window needs replacing.