Condensation on a window is not always a sign that something is wrong. Moisture can form on the room side of the glass when warm, humid air meets a cold surface. It can also appear on the outside of energy-efficient glazing during cool mornings. However, condensation trapped between the two panes usually points to a problem with the sealed glass unit.
At Park Lane Windows, we understand how frustrating misted glazing can be. As well as affecting your view, it may indicate that the window is no longer performing as intended. Here is why it happens and what you can do about it.
How double glazing works
Double glazing consists of two panes of glass separated by a sealed cavity. This space acts as an insulating barrier, helping to reduce heat transfer through the window. The edges of the unit are sealed to prevent moisture from entering the cavity.
When that seal fails, air containing water vapour can get between the panes. As temperatures rise and fall, the vapour turns into condensation. You may first notice a light mist, but the moisture can eventually develop into droplets or a cloudy film that does not wipe away.
Why do sealed units fail?
Age is one of the most common causes. Window seals are designed to last for years, but constant exposure to sunlight, cold weather, and changing temperatures can gradually affect them. The glass and surrounding materials expand and contract as conditions change, placing repeated pressure on the edge seal.
Poor installation may also cause early failure. If a sealed unit is fitted incorrectly, placed under pressure or allowed to sit in water within the frame, its lifespan may be reduced. Damage to the glass or spacer can have a similar effect.
Movement within the building or window frame can also put stress on the unit. Even small changes may weaken an ageing seal. Once moisture has entered the cavity, opening windows or improving ventilation will not remove it because the problem is inside the glass unit.
Is internal condensation different?
Yes. Condensation on the inside surface of a window is generally linked to moisture levels within the home. Cooking, showering, drying clothes indoors, and limited ventilation can all increase humidity. Regular ventilation and using extractor fans can help manage this type of condensation.
The key difference is whether you can reach the moisture. If it wipes away from the inner pane, the sealed unit has probably not failed. If it remains trapped between the panes, professional assessment is recommended.
Can misted double glazing be repaired?
Cleaning the panes will not solve condensation inside a sealed unit. In many cases, the affected glass unit can be replaced while the existing frame remains in place. Whether this is the right option depends on the condition, age and performance of the complete window.
If several units have failed or the frames are showing signs of wear, replacement windows may offer better value over the longer term. Modern uPVC and aluminium windows can improve thermal performance, security and appearance while reducing draughts and unwanted outside noise.
Park Lane Windows supplies a choice of uPVC and aluminium windows to suit different homes and preferences. Our window range includes practical designs for both traditional and contemporary properties, with options to complement your existing exterior.
Get Prepared for Winter with Park Lane
Condensation between panes should not be ignored. Although it is not usually an urgent safety concern, a failed unit can reduce insulation and leave your windows looking permanently misted.
If you are unsure whether your glazing has failed, get in touch with Park Lane Windows. Our team can discuss your requirements and help you consider the most suitable replacement options for your property. Get your quote today.
