Carshalton · Greater London
Misted Glass Repair in Carshalton
We can quote for replacing one misted unit or a full set across homes in Carshalton, with low-E and obscure upgrades available at the same time.
- SM5
- SM1
- SM6
- Guide from £155
Blown double glazing units across Carshalton
Condensation on the room-side surface of the glass is not the same problem. It usually comes from humid indoor air meeting a cold pane and can be wiped away. Only mist trapped between the two panes means the sealed unit itself has failed and needs replacing.
The price of replacing misted units depends on the size of each unit, the glass specification, any bars or decorative features, how many units are done together, and access. Several units on one visit usually cost less each than separate visits for single windows.
Once the seal has failed, any argon or other insulating gas in the cavity has escaped and been replaced by ordinary damp air. The unit insulates less well than when it was new, and moisture inside can gradually leave deposits that dull the glass.
A misted unit is a good opportunity to upgrade an older plain glass unit to one with a low-emissivity coating and gas fill. The new unit reduces heat loss through the glass and keeps the room-side pane warmer, without any change to the frame.
Included as standard
- Survey to confirm the mist is inside the unit
- Measurement of each failed sealed unit
- Removal of old units and cleaning of rebates
- Made-to-measure replacement units matching your windows

Carshalton at a glance
- Postcodes covered
- SM5, SM1, SM6 and the surrounding area, including Wallington, Sutton and Mitcham
- Coast
- Carshalton is well inland, around 38 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Carshalton the midwinter sun reaches about 15° above the horizon at noon, with roughly 7.6 hours of daylight, rising to about 62° and 16.4 hours in midsummer. Units on sunny south and west elevations go through bigger daily temperature swings, which stresses the edge seal over time. In colder, darker months, mist between the panes is often most visible, so the survey is a good time to confirm failure.
- Access and setting
- Older rural homes may have timber frames or units of non-standard sizes, so careful measuring at the survey matters. Exposed sites with driving rain place more strain on seals, and the glazier checks frame drainage and bead condition before fitting.
- Rules in England
- Approved Document K requires safety glass in critical locations in England: glazing in doors and in side panels within 300 mm of a door, up to 1500 mm above floor level, and any glazing in walls or partitions up to 800 mm above floor level.
Guide prices in Carshalton
| Typical job | Guide price inc VAT |
|---|---|
| One misted unit, 600 × 900 mm | £155 – £195 |
| Two misted units, 600 × 900 mm | £305 – £395 |
| Four misted units, 600 × 1100 mm | £685 – £875 |
| Misted unit in a door, toughened | £305 – £385 |
Get a guide price for your size
Approved Document L sets the minimum energy performance for replacement windows and doors in existing homes in England: a U-value of 1.4 W/m²K, or Window Energy Rating band B for windows; doors can instead meet a Door Set Energy Rating (band B, or band C for doors more than 60% glazed); rooflights need 2.2 W/m²K.
Specification choices
Obscure glass unit
Patterned glass for bathrooms, landings and front doors, chosen to match existing obscure panes or to add privacy.
Laminated safety unit
A unit with laminated glass that holds together if broken, useful for ground-floor security and safety in critical locations.
Georgian bar or leaded
Decorative bars or lead designs remade to match the originals so the new unit lines up with neighbouring windows.
Misted Glass Repair in Carshalton: questions
Does misted double glazing lose heat?
A misted unit usually insulates less well than when it was new, because any insulating gas in the cavity has escaped and been replaced with damp air. The mist itself also reduces clarity. Replacing the unit restores a sealed cavity, and choosing a low-E unit can improve on the original performance where the old unit was plain glass.
How much does it cost to replace a misted sealed unit?
The cost depends on the size of the unit, the glass type, any Georgian bars, leaded or obscure features, how many units are done together, and access to the window. Larger units, safety glass and upper-floor windows cost more. See the guide prices for typical sizes, then get a written quote for your exact windows.
Are misted units covered by a guarantee?
Often they are, for a period after installation. Many sealed unit manufacturers guarantee against misting, and the terms are set out in the paperwork from the original installer. If your units are still covered, contact that installer first. Units we supply carry manufacturer guarantees, and the terms are confirmed in writing with your quote.
How can I stop new sealed units misting early?
Keep the drainage slots at the bottom of the frame clear, so rainwater does not sit around the unit edges. Avoid pressure washing the seals, and do not paint over glazing gaskets. Check that opening sashes close properly, as a dropped sash can stress the unit. Report any cracked beads or failed gaskets early.
Do you cover Carshalton for misted glass repair?
Yes. We can quote for misted glass repair across Carshalton and the surrounding Greater London area, including postcode districts SM5, SM1 and SM6, and nearby Wallington, Sutton and Mitcham. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
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Free survey for new glazing, clear guide prices and one point of contact for every glazing job.