Misted or Cloudy Double Glazing? Here’s How to Fix It Without Replacing the Whole Window

If your once-clear windows have turned foggy or developed a cloudy haze between the panes, you’re not alone. Misted double glazing is one of the most common problems homeowners in Milton Keynes face, especially as their windows age. The good news is that it doesn’t always mean you need a brand-new window. In many cases, a simple sealed unit replacement restores clarity, warmth, and energy efficiency for a fraction of the cost.

Why Double Glazing Mists Up

Double-glazed windows are made of two panes of glass with a layer of insulating gas sealed between them. Over time, that seal can fail. When it does, moisture creeps into the gap, forming condensation that can’t be wiped away.
Common causes include:

• Natural wear and tear from sunlight and temperature changes

• Poor installation or cheap original materials

• Excessive cleaning chemicals breaking down the perimeter seal

• Age — most sealed units last around 10 to 15 years

Once the seal fails, the window’s insulating performance also drops, allowing draughts and heat loss that drive up energy bills.

Signs You Have a Broken Down Sealed Unit

You might notice:

• Persistent condensation inside the glass panes

• Cloudy patches that appear and disappear with temperature changes

• A slightly colder feel around the affected window

• Black spotting or moisture staining between the panes

If you spot any of these, the sealed unit has likely failed and needs attention.

Repair Options: Do You Need to Replace the Whole Window?

Not at all. In most cases, you only need to replace the glass unit, not the entire frame.
At MK Doors & Windows, we measure up the faulty pane, manufacture a new energy-efficient sealed unit, and fit it neatly back into your existing frame — all without disturbing surrounding plaster or trim.

This process is:

• Fast: Most replacements are completed within a few days.

• Clean: No mess or heavy construction work.

• Affordable: Typically 60–70% cheaper than fitting new windows.

• Sustainable: Keeps your existing frames out of landfill.

If your window frames are in good condition, sealed-unit replacement is the smartest and most cost-effective fix.

How the Process Works

1. Inspection & Quote: Our local team visits your home to confirm the issue and measure the glass.

2. Manufacture: We order or cut a matching, thermally efficient double-glazed unit.

3. Installation: The misted unit is removed, the new one sealed and fitted in its place.

4. Clean & Test: We check alignment, seals, and operation before leaving everything spotless.

The result? Crystal-clear windows and restored insulation — without replacing frames that still have years of life left.

Can It Be Prevented in the Future?

A few small habits help extend the life of your new sealed units:

• Avoid pressure-washing or harsh chemical cleaners around the seals.

• Maintain good ventilation indoors to reduce moisture build-up.

• Wipe away surface condensation promptly during cold spells.

• Keep trickle vents clear to allow air circulation.

Quality manufacturing and professional fitting also make a huge difference. That’s why all replacement glass from MK Doors & Windows comes with an insurance-backed guarantee for complete peace of mind.

Local Expertise You Can Rely On

Based in Milton Keynes, our friendly team has more than 25 years of experience repairing and replacing double glazing across Newport Pagnell, Bletchley, Olney, Woburn Sands, and nearby towns. Whether it’s one misted window or a full set of replacements, we’ll restore your home’s comfort quickly and professionally.