Northolt · Greater London
Misted Glass Repair in Northolt
Clear glass again in Northolt: replacing blown double glazing units restores the view and a sealed cavity while your existing frames stay in place.
- UB5
- UB6
- HA2
- Guide from £155
Blown double glazing units for homes and businesses in Northolt
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Once the seal has failed, any argon or other insulating gas in the cavity has escaped and been replaced by ordinary damp air.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.
If the misted unit is in a door, beside a door or low down near the floor, the replacement should be safety glass. In England, Approved Document K sets out these critical locations, and the replacement unit should meet them even if the original glass did not.
Early seal failure often shows only on cold mornings or after rain and clears during the day. As the desiccant fills, the mist lasts longer and white mineral staining can form on the inner faces. Staining inside the unit cannot be removed by cleaning from either side.
What's included
- Made-to-measure replacement units matching your windows
- Measurement of each failed sealed unit
- Fitting on packers with drainage slots checked
- Removal of old units and cleaning of rebates

About Northolt for this job
- Postcodes covered
- UB5, UB6, HA2 and the surrounding area, including Greenford, Harrow and Southall
- Coast
- Northolt is well inland, around 52 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Northolt 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 Northolt
| 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.
Options to choose between
Toughened safety unit
Both panes toughened, for misted units in doors, beside doors or low down where safety glass is required.
Low-E upgrade unit
A coated pane and gas-filled cavity that reduce heat loss compared with older plain glass units, fitted in the same frame.
Laminated safety unit
A unit with laminated glass that holds together if broken, useful for ground-floor security and safety in critical locations.
Misted Glass Repair in Northolt: questions
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.
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.
Can you clean the inside of a misted double glazing unit?
Not without breaking the seal. Some firms drill the glass, flush the cavity and fit a small vent, which can clear the mist for a while. It does not restore an airtight seal or gas fill, and white staining may not fully clear. Replacing the unit is the reliable way to restore a clear, sealed cavity.
Can misted double glazing be fixed without replacing the window?
Yes. In most cases only the sealed unit needs replacing, not the frame. The glazier removes the beads, lifts out the misted unit and fits a new one made to the same thickness. Your frames, hinges, handles and locks stay as they are, provided they are in good condition, which the glazier checks at the survey.
Do you cover Northolt for misted glass repair?
Yes. We can quote for misted glass repair across Northolt and the surrounding Greater London area, including postcode districts UB5, UB6 and HA2, and nearby Greenford, Harrow and Southall. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
Get a written quote in Northolt
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.