Repair guide
Misted or Cloudy Double Glazing: What It Means and What It Costs to Fix
By the Newcastle Window and Door Repairs team
Last updated:
A cloudy patch that will not wipe away, water droplets sitting between the panes or a permanent haze in bright sunlight all point to the same thing. The sealed unit has failed and the cavity between the two panes is no longer airtight.
This is the single most common call we get, and it is almost never a reason to replace the whole window. The glass is a separate component from the frame and can be swapped on its own.
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What has actually failed
A double glazed unit is two panes of glass held apart by a spacer bar, with a perimeter seal keeping the cavity airtight and a drying agent inside the spacer soaking up any remaining moisture. Weather exposure, heat movement and frame settlement gradually break that seal down.
Once air can get in, the drying agent saturates and moisture condenses on the inner faces of the glass. Because that moisture is sealed between the panes, no amount of cleaning inside or outside the window will touch it.
Signs to look for before you call
- Condensation or droplets trapped between the panes rather than on the surface
- A cloudy or foggy patch that stays after cleaning both sides
- White chalky staining along the bottom edge of the glass
- Rainbow style smears visible when the sun is low
- The room feeling colder near the window than it used to
Misted double glazing repair
- Condensation or water droplets trapped between the panes
- A permanent cloudy or foggy patch that will not wipe away
- White chalky staining along the bottom of the glass
What the repair involves
We measure the failed unit, check the frame, beading and drainage, and order a made to measure replacement in the correct thickness, gas fill and pattern. On the fitting visit the beads come off, the old unit lifts out, the rebate is cleaned, new packers go in and the new unit is bedded and tested.
Most single units are swapped in well under an hour, and a full house of units is usually completed in one visit. Your frames, cills and internal finishes are untouched.
Worth upgrading while the glass is out
Because the unit is being made from scratch, this is the cheapest moment to improve the glass rather than simply match it. Low emissivity glass warms a cold room, toughened or laminated glass covers safety requirements, obscure patterns suit bathrooms and acoustic glass helps on a busy road.
Guidance on cost
Typical price ranges
Guidance only. Size, specification, access and frame condition affect the price; a free inspection confirms it.
| Work and what affects its cost | Typical range |
|---|---|
| Standard sealed unit, small to medium windowClear or low emissivity glass in a normal opening | around £70 to £160 per unit fitted |
| Large or bay window unitSize, weight and access all affect the price | around £150 to £350 per unit fitted |
| Toughened, laminated, obscure or leaded style unitDepends on the specification and pattern matching | adds roughly 20 to 60 per cent |
| Several units on one visitOne visit and one delivery spread across the job | lower price per unit |
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Questions
Frequently asked
Can misted double glazing be cleaned or dried out?
No. The moisture is sealed between the panes, so it cannot be reached from inside or outside. Replacing the sealed unit is the only genuine fix.
Do I need a whole new window if the glass is misted?
Almost never. If the frame, hinges and locks are sound, only the sealed unit is replaced, which costs a fraction of a new window.
How long does a replacement unit take to arrive?
Units are made to measure, so there is normally a short wait after measuring, followed by a quick fitting appointment.
Will the new unit look different from my other windows?
It should not. We order it in the same thickness and pattern as the original, so it sits in the frame like the rest.
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