Portsmouth · Hampshire
Misted Glass Repair in Portsmouth
Clear glass again in Portsmouth: replacing blown double glazing units restores the view and a sealed cavity while your existing frames stay in place.
- PO1
- PO5
- PO2
- Guide from £155
Condensation between panes for homes and businesses in Portsmouth
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 new unit has to match the overall thickness of the old one so it sits in the existing rebate and takes the original beads. The glazier also notes any Georgian bars, leaded designs or obscure patterns so the replacement matches the other windows in the room.
Common causes of seal failure include water sitting in the frame rebate because drainage holes are blocked, units fitted without correct packers, strong sun on dark frames, and age. Clearing the drainage slots in the frame helps protect the new unit from the same problem.
A sealed unit has a spacer bar around its edge filled with desiccant, a drying agent that absorbs any moisture inside the cavity. When the edge seal fails, damp air keeps getting in until the desiccant is saturated, and condensation then forms between the panes where it cannot be wiped off.
What's included
- Survey to confirm the mist is inside the unit
- Measurement of each failed sealed unit
- Fitting on packers with drainage slots checked
- Made-to-measure replacement units matching your windows

Local details for Portsmouth
- Postcodes covered
- PO1, PO5, PO2 and the surrounding area, including Gosport, Fareham and Ryde
- Coast
- Portsmouth is about 2 km from the coast or a tidal estuary, so salt air and wind-driven rain are worth planning for. Salt air and wind-driven rain put extra strain on sealed unit edges in coastal homes. Keeping frame drainage clear and gaskets in good order matters more, and the glazier checks both so the replacement unit is not sitting in trapped water.
- Daylight and sun
- In Portsmouth the midwinter sun reaches about 16° above the horizon at noon, with roughly 7.7 hours of daylight, rising to about 63° and 16.3 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
- In flats and terraced streets, replacing misted units often means planning access, parking and carrying units up stairs. Upper-floor windows may need to be done from inside, and conservation areas may require matching bars or glass patterns.
- 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 Portsmouth
| 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.
What you can choose
Laminated safety unit
A unit with laminated glass that holds together if broken, useful for ground-floor security and safety in critical locations.
Toughened safety unit
Both panes toughened, for misted units in doors, beside doors or low down where safety glass is required.
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 Portsmouth: 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.
Why has condensation appeared between my double glazing panes?
Condensation between the panes means the edge seal of the sealed unit has failed. Damp air has got into the cavity, and the drying agent in the spacer bar can no longer absorb it. The cause is often age, water sitting in the frame, poor packing or strong sun on the frame. The fix is to replace the sealed unit.
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.
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 Portsmouth for misted glass repair?
Yes. We can quote for misted glass repair across Portsmouth and the surrounding Hampshire area, including postcode districts PO1, PO5 and PO2, and nearby Gosport, Fareham and Ryde. 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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