Barnet · Greater London
Misted Glass Repair in Barnet
Cloudy, streaky double glazing in Barnet is usually a failed sealed unit, and we can quote to replace it without disturbing the frame.
- EN4
- EN5
- HA8
- N2
- N3
- N12
- Guide from £155
Blown double glazing units in Barnet
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.
Replacing a misted unit is usually a short job per window once the new unit has been made. The old unit is lifted out, the frame rebate and drainage cleaned, and the new unit set on packers so the weight is supported and any opening sash stays square.
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.
Check the paperwork for your windows before booking. Many sealed units come with a manufacturer guarantee against misting, and if your windows are still covered, the original installer or manufacturer may be responsible for replacing the failed unit under its terms.
What's included
- Measurement of each failed sealed unit
- Fitting on packers with drainage slots checked
- Written quote fixing the price for the specification
- Made-to-measure replacement units matching your windows

Working in Barnet
- Postcodes covered
- EN4, EN5, HA8, N2, N3, N12, N20, NW4, NW7, NW11 and the surrounding area, including Potters Bar, Borehamwood and Finchley
- Coast
- Barnet is well inland, around 45 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Barnet 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 Barnet
| 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
Toughened safety unit
Both panes toughened, for misted units in doors, beside doors or low down where safety glass is required.
Obscure glass unit
Patterned glass for bathrooms, landings and front doors, chosen to match existing obscure panes or to add privacy.
Like-for-like clear unit
A direct replacement matching the thickness and look of the original unit, for windows where no change in performance is needed.
Misted Glass Repair in Barnet: questions
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.
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.
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 long does it take to replace a misted unit?
There are usually two visits. The first is a survey to measure each unit. The second is fitting, once the new units have been made to order. Fitting usually takes a short time per window, with little mess. Your quote sets out when the units are expected, and we will tell you honestly when a glazier can attend.
Do you cover Barnet for misted glass repair?
Yes. We can quote for misted glass repair across Barnet and the surrounding Greater London area, including postcode districts EN4, EN5, HA8, N2 and N3, and nearby Potters Bar, Borehamwood and Finchley. 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 Barnet
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.