Misted Double Glazing Replaced in London: New Glass, Same Frames

Cloudiness or water sitting between the panes means one thing: the seal around that sealed unit has failed and damp air is now inside the cavity. It cannot be cleaned, dried or resealed, and it is not a sign the window is finished. The glass unit is a separate part that lifts out of the frame, so we measure it, order a matching replacement and fit it in around three quarters of an hour, leaving the frame, hinges and handles exactly as they are.

Free measure-up and fixed price before any work starts
Toughened, low-E, obscure and Georgian bar units available
Argon-filled, warm-edge spacer bar as standard on residential units
Old unit removed and disposed of — no mess left behind
Frame, beads and rubbers checked and re-sealed while we're on site

A 'misted' or 'blown' double glazed unit is one where the airtight seal around the two panes has broken down. Once moisture gets in, no amount of cleaning will shift it — the unit needs replacing. Ninety per cent of the time we do this without touching the frame, which keeps the job quick, tidy and much cheaper than a full window replacement.

We stock the common sizes and can get bespoke units made and fitted usually within 3–5 working days for London addresses. If it's a bay, a leaded pattern or an obscure privacy glass, send us a photo and we'll come back with a fixed price the same day.

Misting rarely arrives alone. Units on the same elevation tend to fail within a year or two of each other, because they have taken the same sun and the same driving rain since the day they were fitted, so it is worth walking round with a cloth on a cold morning and noting every pane that stays hazy after wiping. Replacing two or three on one visit costs less per unit than calling us back twice.

While the unit is out we can change the specification rather than simply matching it. The usual reasons are a bathroom or a ground floor front window that would be better in obscure glass, a road-facing bedroom that benefits from a laminated outer pane for noise, a door side panel that legally needs toughened glass, or a cold room where a low emissivity coating and an argon fill make a noticeable difference. The frame stays the same, so the only change is the glass we order.

How the repair works

1. Send a photo or call Message a photo or call Mark on 07535 916982. We'll usually quote a fixed price straight over the phone.
2. Measure & order If needed we pop out to measure — always free. Standard units are typically ready in 3–5 working days.
3. Fit & clean up One visit, one unit swapped in around 45 minutes. We test the seal, re-bead and take the old glass away.

Frequently asked questions

Can you repair a misted double glazed unit without replacing it?

No — once the seal between the panes has failed, the unit itself has to be replaced. The good news is the frame nearly always stays, so it's a much smaller job than a whole new window.

How much does it cost to replace a misted unit in London?

Typical residential sealed units start from around £95–£160 fitted depending on size, glass spec and access. We give you a fixed price up front — no surprises on the day.

How long does it take?

Standard clear units are usually fitted within 3–5 working days of the order. The fit itself takes about 45 minutes per unit.

Do you replace units in aluminium and timber frames as well as uPVC?

Yes — we work on uPVC, aluminium and timber-framed windows across London homes and commercial units.

Can misted double glazing be fixed without replacing the window?

Yes. In most cases only the sealed unit has failed, so Mark replaces that unit and keeps the sound frame. The new unit is made to measure for the existing opening.

How do I know if my double glazed unit has failed?

The usual sign is condensation or a milky haze between the two panes that you cannot wipe away from either side. That means the seal around the unit has failed and moisture has got inside.

How long does replacing a misted unit take?

The new unit is made to measure, so it is measured first and fitted once it is ready. Jobs are often same-day where the diary allows, and a fixed price is confirmed first.

Useful guides

Misted unit replacement in north London

Across north London, from Barnet and Haringey to Islington and Camden, misted double glazing is one of the most common repairs Mark is asked about. The approach is the same as anywhere else in his area. The misted sealed unit is taken out and the sound frame is kept, so the window itself stays where it is. The new unit is made to measure to fit the existing opening, which means it sits in the frame just as the original did. A fixed price is confirmed first, before any work starts, so you know exactly where you stand. If the frame, hinges or handles also need attention, those can be looked at on the same visit. For a breakdown of what affects the price, see the misted double glazing cost guide, and for what the misting actually means, read about condensation between glass panes.