Misted Double Glazing

If you’ve noticed misted double glazing on your uPVC windows, you’re seeing condensation trapped between the panes of glass. This common issue, also known as condensation inside double glazing, signals a failure in the sealed unit, often called blown double glazing or a failed sealed unit. At Window Repairs Sutton, we specialise in uPVC window repair for issues like this, helping homeowners in Sutton restore clear views without full window replacement.

What This Usually Means

Misted double glazing occurs when the airtight seal between the two glass panes breaks down, allowing moisture to enter the void. Over time, this condensation builds up, creating a foggy appearance that worsens with temperature changes. It’s not a superficial problem—it’s a sign your window’s insulation properties have failed, potentially leading to higher energy bills and draughts.

This symptom doesn’t affect the window frame or operation initially, but ignoring it can lead to further damage. Unlike external condensation, which clears up when the weather warms, internal misting persists regardless of conditions. It’s a straightforward diagnosis for experienced technicians.

Common Causes

Several factors contribute to misted double glazing. The most frequent is natural wear over 10-20 years, as seals degrade from exposure to heat, cold and UV light.

Manufacturing defects or poor installation can accelerate failure, trapping moisture from the start. Physical impacts, like a stray football or ladder bump, may crack the glass or compromise seals without obvious external damage.

High humidity environments, such as kitchens or bathrooms, exacerbate the issue if ventilation is poor. Frame movement from settling buildings or inadequate window adjustment can also strain the seals.

Safe Checks Before Booking

Before calling for window repair, perform these simple, safe checks to confirm the issue and avoid unnecessary costs.

• Wipe the interior and exterior glass thoroughly—if the mist clears on one side only, it’s likely external condensation from humid air, not a failed sealed unit.
• Inspect all your windows: if misting affects multiple units, it could indicate a broader ventilation or humidity problem in your home.
• Gently press around the window edges for unusual flexing or gaps, which might suggest frame misalignment needing window adjustment.
• Check for water droplets solely between panes during cooler evenings; this confirms internal condensation inside double glazing.

Avoid forcing open stiff windows or using harsh chemicals, as these could worsen alignment or damage seals. These steps help you gather details for our team without risk.

Likely Fixes

Misted double glazing typically requires targeted uPVC window repair, focusing on the sealed unit rather than the entire window. Here’s a decision-style guide to the most likely solutions:

• Primarily foggy with no cracks or leaks? The seal has failed—opt for double glazed unit replacement to restore insulation efficiently.
• Misting plus frame misalignment or draughts? Start with sealed units for double glazing paired with adjustment to prevent recurrence.
• Other symptoms like stiff operation or handle issues alongside mist? Check our full symptoms list to identify combinations, then book a diagnostic visit.
• Recent impact damage visible? Prioritise unit replacement via [/repairs/double-glazed-unit-replacement/], as frames often remain intact.

We handle these repairs with 10+ years of experience, public liability insurance and DBS-checked technicians. Full window replacement is rarely needed, saving you time and money.

FAQs

What causes misted double glazing in newer windows?

Even modern uPVC units can mist due to installation flaws or extreme weather cycles stressing the seals prematurely. If your windows are under 10 years old, check warranty details first.

Can I fix blown double glazing myself?

DIY seal repairs are unreliable and often void warranties. Safe checks are fine, but professional double glazed unit replacement ensures a lasting fix.

How much does repairing misted double glazing cost?

Costs vary by window size and access, but replacing a failed sealed unit is far cheaper than new windows. Contact us for a no-obligation quote tailored to your Sutton home.

Does misted double glazing affect energy efficiency?

Yes, it reduces insulation, leading to heat loss and higher bills. Prompt window repair restores performance without disrupting your home.

Is condensation inside double glazing dangerous?

No immediate health risks, but it can promote mould if untreated. Addressing it via [/parts/sealed-units-double-glazing/] prevents escalation.

Do you repair wooden or sash windows?

We focus on uPVC systems and exclude sash, sliding, tilt-and-turn or wooden windows. See our services for what’s covered.

How quickly can you fix misted double glazing?

We prioritise local Sutton jobs with liability-insured technicians. Book via [/contact/] for the earliest slot.

Call To Action

Spot misted double glazing or condensation inside double glazing? Don’t let it worsen—contact Window Repairs Sutton today on 020 8138 0796 or email info@window-repairs-sutton.co.uk. Our local, insured team delivers reliable uPVC window repair with minimal disruption.

Browse other issues on our symptoms page or explore sealed units and repairs. Get your windows clear again.