Misted Double Glazing: Can It Be Fixed Without a New Window?
If your double glazing looks cloudy, foggy or streaky, and the mist won't wipe off from either side, the problem is inside the glass. The seal that holds the two panes together has failed. The good news is that in most cases you don't need a new window. The glass unit can be replaced in the existing frame.
First, where is the condensation?
On the inside surface (room side): this isn't a fault with the window. It's moisture in the room meeting a cool surface. Better ventilation, extractor fans and not drying clothes indoors usually help.
On the outside surface: on a cold morning this is actually a sign the glazing is insulating well. It clears as the day warms up.
Between the panes: this means the sealed unit has failed, and it's the only one of the three that needs a repair.
Why double glazing mists up
A double-glazed unit is two panes of glass with a spacer bar between them, sealed around the edge. The gap is dry, and the spacer contains a desiccant that soaks up any small amount of moisture. Over the years the edge seal can break down through age, sun, temperature swings or water sitting in the frame. Once it does, damp air gets in, the desiccant fills up, and moisture condenses on the inside faces of the glass.
Once that happens it won't go away. You can't clean it because it's sealed inside, and over time it can leave permanent marks and staining on the glass.
Does it matter?
It's harder to see out of, and it usually gets worse rather than better.
The unit insulates less well once the seal has gone, especially if it was gas-filled.
It can stain the glass permanently if it's left for a long time.
Can it be fixed without replacing the window?
Usually, yes. The frame, hinges and locks are often perfectly fine. We measure the glass unit, have a new sealed unit made to size, and then swap it into the existing frame. It's a much smaller job, and much cheaper, than a whole new window, and you keep your existing frames.
You'll see "demisting" services that drill small holes in the glass and dry it out. The results vary, and the seal is still broken, so we generally recommend replacing the unit.
Can you upgrade at the same time?
Yes. When a unit is being replaced anyway it's a good chance to change the glass. Obscured (privacy) glass for a bathroom, toughened safety glass where it's needed, or a more energy-efficient unit.
Other glass we replace
We also replace cracked, smashed and broken glass in windows and doors. Read more about misted and broken glass replacement.
Get a free quote
Send a photo of the misted window on WhatsApp, ideally with a tape measure across the glass, and we'll give you an estimate. We replace misted and broken glass across Bridgwater, Taunton, Highbridge, Weston-super-Mare, Cheddar, Glastonbury and Wellington. Or request a free quote.
If your double glazing looks cloudy, foggy or streaky, and the mist won't wipe off from either side, the problem is inside the glass. The seal that holds the two panes together has failed. The good news is that in most cases you don't need a new window. The glass unit can be replaced in the existing frame.
First, where is the condensation?
On the inside surface (room side): this isn't a fault with the window. It's moisture in the room meeting a cool surface. Better ventilation, extractor fans and not drying clothes indoors usually help.
On the outside surface: on a cold morning this is actually a sign the glazing is insulating well. It clears as the day warms up.
Between the panes: this means the sealed unit has failed, and it's the only one of the three that needs a repair.
Why double glazing mists up
A double-glazed unit is two panes of glass with a spacer bar between them, sealed around the edge. The gap is dry, and the spacer contains a desiccant that soaks up any small amount of moisture. Over the years the edge seal can break down through age, sun, temperature swings or water sitting in the frame. Once it does, damp air gets in, the desiccant fills up, and moisture condenses on the inside faces of the glass.
Once that happens it won't go away. You can't clean it because it's sealed inside, and over time it can leave permanent marks and staining on the glass.
Does it matter?
It's harder to see out of, and it usually gets worse rather than better.
The unit insulates less well once the seal has gone, especially if it was gas-filled.
It can stain the glass permanently if it's left for a long time.
Can it be fixed without replacing the window?
Usually, yes. The frame, hinges and locks are often perfectly fine. We measure the glass unit, have a new sealed unit made to size, and then swap it into the existing frame. It's a much smaller job, and much cheaper, than a whole new window, and you keep your existing frames.
You'll see "demisting" services that drill small holes in the glass and dry it out. The results vary, and the seal is still broken, so we generally recommend replacing the unit.
Can you upgrade at the same time?
Yes. When a unit is being replaced anyway it's a good chance to change the glass. Obscured (privacy) glass for a bathroom, toughened safety glass where it's needed, or a more energy-efficient unit.
Other glass we replace
We also replace cracked, smashed and broken glass in windows and doors. Read more about misted and broken glass replacement.
Get a free quote
Send a photo of the misted window on WhatsApp, ideally with a tape measure across the glass, and we'll give you an estimate. We replace misted and broken glass across Bridgwater, Taunton, Highbridge, Weston-super-Mare, Cheddar, Glastonbury and Wellington. Or request a free quote.