Serving Bournemouth, Poole, Christchurch and across Dorset
Foggy windows are one of the most common problems we get called out for. The short answer: your windows are foggy for one of three reasons — condensation on the inside of the glass, condensation on the outside, or moisture trapped between the panes of a double-glazed unit. The first two are usually harmless and easy to manage yourself. The third means the sealed unit has failed and needs replacing — and that’s where we can help.
Here’s how to tell which one you’re dealing with.
1. Fog on the inside of the glass (room side)
If you can wipe the fog away with your hand, it’s condensation forming on the inside of the window. This happens when warm, moist air in your home hits the cooler glass surface — most noticeable on cold mornings, in kitchens and bathrooms, or in bedrooms after everyone’s been asleep.
This isn’t a fault with the window. It’s a sign your room has high humidity and not enough ventilation. You can reduce it by opening trickle vents, using extractor fans, drying washing outside where possible, and keeping a little airflow going in colder months. Persistent internal condensation can lead to damp and mould, so it’s worth getting on top of.
2. Fog on the outside of the glass
If the fog is on the outer surface and clears as the day warms up, this is external condensation — dew forming on the cold glass overnight. Counterintuitively, this is a good sign: it usually means your double glazing is doing its job so well that heat isn’t escaping to warm the outer pane. It looks alarming but needs no repair.
3. Fog between the panes — the one that needs fixing
Here’s the important one. If the fog, mist or cloudiness is trapped inside the glass — you can’t wipe it off from either side — the seal around your double-glazed unit has failed. This is often called a blown or misted double glazing unit.
When the seal goes, the insulating gas escapes and moisture gets drawn into the gap between the panes. Once that happens, the fogging is permanent and will only get worse — you may see cloudiness, water droplets, or a permanent milky haze that never clears. Beyond looking unsightly, a blown unit has lost its insulating value, which means colder rooms and higher heating bills.
The good news: in most cases we don’t need to replace the whole window or frame. We can supply and fit a new sealed glass unit into your existing frame — a far cheaper and quicker fix than a full window replacement.
Why it’s so common in Bournemouth
Coastal homes across Bournemouth, Poole and Christchurch see a lot of failed units. Salt air, damp sea weather and the age of a lot of local double glazing all put extra strain on the seals. If your windows were fitted 10–20 years ago, blown units are one of the most common issues we see.
Quick test: which type of fog do you have?
- Wipe it — does it clear? Inside or outside = condensation (usually harmless).
- Can’t wipe it off either side? The fog is between the panes — the unit has blown and needs replacing.
Can foggy double glazing be repaired?
A blown unit can’t be “de-fogged” reliably — despite what some online tricks claim, drilling and drying-out methods don’t restore the seal or the insulation, and the fog returns. The proper, lasting fix is a replacement sealed unit fitted into your existing frame. It’s quick, tidy, and far more affordable than replacing the whole window.
Get your foggy windows fixed — call JCarter Locksmiths
If your windows are misted between the panes, we can help. JCarter Locksmiths provides fast, affordable glazing repairs across Bournemouth, Poole, Christchurch and the surrounding Dorset area:
- ✅ Blown & misted double glazing replaced
- ✅ Fitted into your existing frames — no full window replacement needed
- ✅ Free, upfront quotes with no call-out fee
- ✅ Family-run, military veteran-owned, 100’s of five-star reviews
📞 Call or WhatsApp us on 07842 252 025 🌐 See our full glazing services or request a free quote.
Frequently asked questions
Are foggy windows dangerous? Not dangerous, but a blown unit loses insulation and drives up heating costs, and internal condensation can cause damp and mould over time — so both are worth addressing.
Do I need to replace the whole window? Usually not. If the frame is sound, we simply fit a new sealed glass unit into it, which is quicker and cheaper than a full replacement.
How much does it cost to fix a foggy double-glazed window? It depends on the size and type of glass, but replacing a sealed unit is far cheaper than a new window. We’ll give you a clear, upfront quote with no call-out fee.
How quickly can you come out? We cover any BH postcode and can often fit glazing work in promptly. Give us a call and we’ll arrange a convenient time.
