Understanding Condensation Between Your Double-Glazed Panes
Noticed fog or cloudiness inside your double-glazed windows? That’s condensation between the panes – a common issue for many UK homeowners. While it might seem like a minor annoyance, it’s actually a sign your window unit has failed. In this article, we’ll explain what causes it, how to spot it early, your options for fixing it, and whether you need a full replacement.
What Usually Causes Condensation Between Panes?
Double-glazed units work by trapping air (or gas) between two glass panes to insulate your home. When the seal around the glass ages, breaks, or becomes damaged, moisture seeps in. This leads to:
- Misting or fogging: usually appears as a cloudy patch inside the unit that won’t wipe away from either side.
- Blown double glazing: the technical term for a unit with a failed seal letting in moisture.
Causes of seal failure can include:
- Age – most units last 10–20 years, but older ones naturally wear down.
- Temperature changes – weather extremes cause the materials to expand and contract.
- Poor installation – even a small error with alignment or sealing can lead to premature failure.
- Faulty manufacturing – unfortunately, some units aren’t made to last.
Is It Just Cosmetic?
Not really. While the visual mist may be the first thing you notice, condensation trapped between panes is a clear sign the seal is no longer doing its job. That means:
- Your thermal insulation has weakened, making your home colder and less energy efficient.
- There’s potential for mould growth if the trapped moisture becomes persistent.
- It can affect the value or appeal of your home, especially to buyers.
Repair vs Replacement: What Are Your Options?
Many people assume fixing it means replacing the whole window, but that’s rarely the case. If your frames (UPVC, aluminium or timber) are in good condition, you can often replace just the blown glass unit.
At Get My Windows Fixed, we specialise in this exact type of repair. Our approach causes minimal disruption and keeps your costs lower than full window replacement.
How Much Does It Cost?
Prices vary by size and glass type, but replacing a misted double-glazed unit generally starts at £85–£120 for a standard window. Larger windows, special coatings (like low-e or toughened glass), or shaped panels will cost more.
How Long Does It Take?
If we have your unit spec or can quickly measure it on-site, replacements usually take 30–60 minutes per window. No mess, no frame removal, no fuss.
DIY: Can You Check It Yourself?
Yes – here’s how to tell if your condensation issue is between the panes:
- Can’t wipe it away from inside or outside? It’s between the glass.
- The fogging appears in certain light conditions or weather changes.
- You may see water droplets or smears ‘trapped’ inside the unit.
Still unsure? That’s where we come in. We offer free surveys and honest advice, with no pushy sales. If your frame is fine, we won’t try to sell you a new window.
Clear Views and Cosy Homes
Condensation between the panes means your double glazing isn’t performing at its best – but that doesn’t mean a full replacement is needed. Most misted windows can be fixed by simply replacing the glass unit, restoring energy efficiency and a clear view.
If you’re dealing with foggy glass or wondering what’s going on inside your window, Get My Windows Fixed is here to help.