Misted Double Glazing Repair in Bristol
Cloudy, streaky, or permanently misted glass between the panes means the sealed unit has failed. It won't clear on its own and it can't be resealed — but you don't need a new window. We replace the glass unit only; the frame stays.
Family-run Bristol business · 20 years trade experience · Send us an enquiry with photos and we'll get back to you
Signs your double-glazed unit has failed
- A permanent cloudy or misty appearance between the panes — not on the surface
- Streaky marks or tide lines inside the unit that don't wipe off
- Condensation that appears between the panes in cold or damp weather
- The glass looks clear in warm dry weather but mists up when it's cold — the seal is on its way out
A failed sealed unit, and the same window after we replaced the glass only. The frame was never touched. From £165 + VAT.
A second job, this one in Redland. In the first photo you can barely make out the fence through the failed unit; in the second it is sharp. Same frame, new glass.
Why does double glazing go misty?
A double-glazed unit is two panes bonded together with a hermetic seal, enclosing a layer of gas (usually argon) between them. The seal keeps moisture out and maintains thermal performance.
Over time — typically 15–25 years, sometimes sooner on south-facing windows — the seal perishes. Once it fails, moisture gets between the panes. It can't escape, so it condenses and creates the permanent cloudy appearance.
The misting cannot be cleaned off and the seal cannot be repaired. The proper fix is usually to replace the sealed glass unit, not reseal the old one.
Why glass mists up & what to do
Not all cloudy glass is the same. Here's what the different signs usually mean and the best next step. These are general guides — send us a photo and we'll confirm before anything is agreed.
| What you're seeing | What it usually means | What to do next |
|---|---|---|
| A permanent cloudy or misty film between the panes | The sealed unit's seal has failed and moisture is trapped inside the glass. | Usually a glass-only sealed unit replacement — the frame stays. See pricing below. |
| Streaky marks or tide lines that won't wipe off | The same failed seal — mineral deposits left as trapped moisture evaporates and re-condenses. | Replacing the sealed unit is normally the only fix. See pricing below. |
| Clear in warm dry weather, misty when it's cold | The seal is on its way out — early-stage failure that usually worsens over time. | It won't reseal itself; it can be replaced now or kept an eye on. Send a photo and we'll advise. |
| Misting or condensation on the room-side surface you can wipe off | That's surface condensation from humidity in the room, not a failed unit. | Often a ventilation issue rather than a glass fault — the glass itself may be fine. |
| Cloudy glass in a door rather than a window | The same sealed-unit failure, but door glass normally needs to be toughened safety glass, and we quote it that way. | See door glass replacement — we quote toughened safety glass as standard for door panels. |
Not sure which it is? Send us a photo and we'll tell you what's likely needed and give you a clear price first. Weighing up the options? See our guide on repairing or replacing misted units.
What we do — and what we don't
The frame and the glass are separate. When the sealed unit fails, the frame is usually still fine — it just needs a new glass unit. We:
- Visit to measure the failed unit precisely
- Order a replacement sealed unit to the exact size (often around 5–7 working days)
- Return to remove the old unit, fit the new one, and refit the beading
- Test the finished result — a properly sealed, thermally efficient pane
We do not replace the frame unless it has failed independently — that would be an unnecessary cost.
Sealed units are manufactured to measure, so there is a lead time. From your call to a finished clear window, many jobs are completed in around 7–10 days. Many units can be fitted in a short visit, depending on access, size and frame condition.
What does it cost?
Replacing a sealed unit costs a fraction of replacing the whole window. The frame stays — you're paying for glass and labour only.
| Option | Typical cost (+ VAT) |
|---|---|
| Sealed unit replacement (glass only) | From £165 |
| Full window replacement (frame + glass) | From £600 |
We confirm the price after measuring — larger or non-standard units cost more, but the price is always agreed before anything is ordered.
Misted window? Send us a photo.
We can usually tell from a photo whether it's a failed sealed unit and give you a rough price before visiting. Get a free quote below. If the glass is in a door, see door glass replacement — toughened safety glass is required.
Part of our full glass replacement service in Bristol. Not sure what to photograph? See what photos to send.
Frequently asked questions
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The sealed unit needs replacing — it cannot be repaired. Once the seal has failed, moisture is inside the unit and there is no reliable way to dry it out or reseal it. The good news is that only the glass is replaced. The frame, the hinges and the handles all stay.
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Almost never. If the frame is sound, replacing the sealed unit costs from £165 + VAT against roughly £600 + VAT for a complete new window. We will tell you honestly if the frame has had its day, but in most cases it has not.
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From £165 + VAT per unit. Size, the type of glass and whether it is toughened or patterned all move the price. We confirm it before anything is ordered.
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The unit has to be made to measure, so there is a wait between measuring and fitting. The fitting visit itself is usually short — often under an hour for a standard window.
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We match the glass specification, including obscure patterns where we can. Send a photo and we will tell you what we can match before you commit to anything.
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Sealed units fail individually. It is usually the one that takes the most sun, the most weather or the most temperature swing. One failing does not mean the rest are about to.
Get a Free Quote
Describe the problem and add photos if you have them. We'll usually reply during working hours with advice and a price where possible.