Why Do My Double-Glazed Windows Mist Up Inside?
If you’ve noticed a foggy or misty patch that won’t wipe away from the inside of your double-glazed window, don’t worry — you’re not alone. This is a common problem many UK homeowners face, especially as windows age or face harsh weather. The good news is: there’s a practical fix.
What Causes the Mist Inside Double Glazing?
Double-glazed windows are sealed, insulating units designed to trap air (or gas) between two panes of glass. This helps keep your home warm, quiet, and energy-efficient. But over time, that seal can fail. When it does, moisture from the air sneaks in between the panes and gets trapped, showing up as mist or condensation that you can’t clean from the inside or outside.
Here are a few common reasons why this happens:
- Age: Seals deteriorate over time — many older units naturally lose their airtight seal after 10–20 years.
- Weather exposure: Repeated heating, cooling, and exposure to rain and cold can weaken seals.
- Poor installation: If the original window wasn’t installed properly, it’s more likely to develop faults.
- Frame movement: House settling or thermal expansion can affect the tightness of the seal.
Will It Go Away on Its Own?
No — once moisture gets in between the panes due to a blown or failed seal, it’s there to stay unless the unit is repaired or replaced. There are no DIY fixes that truly remove moisture from between sealed panes permanently.
Repair or Replacement: What Are Your Options?
Repair Isn’t Always the Right Answer
You might come across companies offering to “remove condensation” without replacing the glass. These are often temporary fixes, involving drilling into the glass and trying to vent out the moisture. The core issue — the broken seal — remains, and the problems usually come back.
Glass-Only Replacement: The Best Solution
Thankfully, you don’t need to replace the entire window frame. In most cases, just the glass unit (also called a double-glazed sealed unit) can be replaced. This is quicker, more cost-effective, and keeps your existing frames, sills, and décor intact.
At Get My Windows Fixed, we specialise in replacing just the faulty glass unit inside your window, restoring full clarity and insulation without unnecessary extras.
How Much Does It Cost?
The cost depends on the size and style of your window. For a typical UK window, you can expect to pay approximately:
- Small window (e.g. bathroom): £90–£120
- Medium-sized window (e.g. bedroom): £120–£160
- Large window (e.g. bay window panel): £160–£220+
We always give a no-obligation quote, and our surveys are free. There’s no callout fee — just honest pricing.
How Long Does It Take to Fix?
Replacing misted glass typically takes about 20–30 minutes per window once the new unit is manufactured. Lead time for glass units is usually 3–7 working days after measuring. So from quote to finish, the whole process is quick and hassle-free.
Can I Prevent It From Happening Again?
While no double glazing lasts forever, you can help extend its life by:
- Keeping trickle vents open to control indoor humidity
- Ensuring windows aren’t constantly wet from condensation or poor airflow
- Getting high-quality sealed units with a trusted guarantee
Clear Views and Cosy Homes
It’s easy to ignore misted windows, but over time, they reduce your home’s insulation and let precious heat escape. Don’t put up with poor visibility and higher heating bills — replacing the glass is simpler than you might think.
Get My Windows Fixed offers local, friendly glass replacement that’s quick, affordable, and built to last. No mess, no gimmicks — just clear panes and warmer rooms.