If you’ve noticed a cloudy film or droplets that won’t wipe away on your windows this autumn, the problem is almost certainly inside the glass, not on it. The good news is that misted double glazing repair rarely means a whole new window. In most cases, only the sealed glass unit needs replacing.

Here’s how to tell whether your double glazing has failed, why it happens, and what a repair actually involves.

Is the condensation inside or outside the glass?

Condensation on the room side of a window is common on cold mornings. It comes from moisture in the air indoors, and a cloth or better ventilation usually deals with it. Condensation on the outside of the glass is normal too, and usually a sign your glazing is keeping heat in.

Condensation between the panes is different. Try this simple check:

1. Wipe the inside of the glass with a dry cloth.
2. Wipe the outside of the glass.
3. If the mist or droplets are still there, the moisture is trapped between the two panes.

That means the seal around the unit has failed, sometimes called a blown double glazed unit. It won’t clear on its own, and it tends to get worse over time.

Why double glazing mists up

A double glazed unit is two panes of glass held apart by a spacer bar and sealed around the edge. The gap is kept dry, and in many units it is filled with an insulating gas. As long as the seal holds, no moisture can get in.

Over the years, that seal is put under constant strain:

• Temperature changes. Glass and frames expand on warm days and contract on cold nights, which gradually weakens the seal.
• Age. Like any seal, it doesn’t last forever, and older units are far more likely to fail.
• Standing water. If the drainage channels in the frame are blocked, water can sit against the bottom edge of the unit and break down the seal.

Once the seal goes, damp air finds its way into the gap. You’ll usually spot it first on cold autumn and winter mornings, when the temperature difference is greatest.

Does misted double glazing matter?

A misted unit isn’t just a cosmetic problem:

• Your view is spoiled. The haze often leaves permanent marks on the inner surfaces of the glass.
• You lose insulation. If the unit was gas filled, that gas has likely escaped, so the window is doing less to keep the heat in.
• It gets worse. More moisture gets in over time, and the build up becomes harder to ignore.

If your windows also feel draughty, have a look at our guide to energy leaks you can fix with simple UPVC window repairs.

Replace the unit, not the window

Many companies will tell you a misted window means a new window. Often, it doesn’t. If the frame is in good condition, we simply replace the sealed glass unit. It’s quick and clean, and it costs a fraction of a full window replacement.

Think of it like a flat tyre. You’d replace the tyre, not the car.

When we replace a misted unit, we:

1. Measure the existing unit so the new one fits the frame exactly.
2. Remove the glazing beads and take out the failed unit.
3. Fit the new sealed unit and refit the beads.
4. Check the window opens, closes and locks properly.

It’s also a good chance to fix anything else that’s bothering you. If a handle is stiff or a hinge has dropped, we can repair those at the same visit. See our locks, handles and hinges page for details. If you’d like to change the look of the window, we can also fit leaded or bevelled glass in the new unit.

When a new window makes more sense

Replacing the unit is the right answer most of the time, but not always. A new window may be better value if:

• The frame is warped, cracked or rotten.
• Several units in the same window have failed.
• The window no longer closes or locks securely, even after repair.
• You’re updating the style of the whole house.

We’ll always tell you honestly which option makes sense. If a new window is the better choice, take a look at our UPVC windows range.

Misted double glazing repair in Staffordshire and Cheshire

Window Repair Centre replaces misted double glazed units for homes across Stoke-on-Trent, Staffordshire and Cheshire. We’re a Which? Trusted Trader, with showrooms in Cheadle, Alsager and Fenton.

To get a price, request a free quote online and we’ll reply within 24 hours. Or call us free on 0800 0436 744, Monday to Friday 9am to 5pm and Saturday 9am to 1pm.

Misted Double Glazing FAQs

Can misted double glazing be fixed without replacing the window? Yes. If the frame is sound, only the sealed glass unit needs replacing. It’s quicker and costs a fraction of a new window.

Can I clear condensation between the panes myself? No. Once the seal has failed, moisture keeps getting in, and the gap can’t be properly dried and resealed at home. Replacing the unit is the reliable fix.

Why does my double glazing only mist up in the mornings? The temperature difference between the inside and outside glass is greatest on cold mornings, so trapped moisture condenses then. It often clears during the day, but the seal has still failed.

Do you cover my area? We repair windows across Stoke-on-Trent, Staffordshire and Cheshire, with showrooms in Cheadle, Alsager and Fenton.