Double Glazing Repairs: What Can Be Fixed, 2026 Costs — and When Replacement Really Is Cheaper
The window industry has a well-rehearsed answer to every problem: "you need new windows." Usually, you don't. Most double glazing faults — misted glass, stiff handles, dropped hinges, draughts — are component failures on a frame that has decades left in it. Repairing the component costs a fraction of replacement. Here's what each fix costs in 2026, and where repair genuinely stops making sense.
In short: Double glazing repairs typically cost £50–£350 per window. A misted (blown) unit costs around £55–£180 to replace within the existing frame — against roughly £450 for a whole new window, an ~80% saving. Handles, hinges and locks run £50–£250, with simple handle swaps from about £30.
Repair costs at a glance
| Problem | Typical repair cost | The replacement it avoids |
|---|---|---|
| Misted / blown sealed unit (condensation between panes) | £55 – £180 (large units up to £400) | ~£450 per new window |
| Broken or stiff handle | from ~£30 | full window |
| Dropped or worn hinges (sash catches, draughts) | ~£50 – £150 | full window |
| Failed lock / uPVC mechanism | £50 – £250 | full window / new door |
| Whole-house blown units (3-bed semi) | £1,400 – £2,500 | many thousands in new windows |
The pattern is consistent: repairing the failed part saves 80–90% against replacing the window — a misted unit at ~£85 versus ~£450 for a new window, a £45 handle versus a £450 frame. The frame itself, whether uPVC or aluminium, rarely fails; it's the moving and sealed parts that wear.
The big one: misted glass between the panes
Condensation inside the glass sandwich means the sealed unit has failed and moisture has crept in — the glass unit needs swapping, not the frame. A glazier measures the unit, orders a replacement pane-set and fits it into your existing frame, usually within an hour per window. Condensation on the room side of the glass is a different story entirely (humidity, not window failure) — our condensation and misted glazing guide walks through telling the two apart before you spend anything.
The uPVC clinic: handles, hinges, locks
- Stiff or floppy handles: Usually the handle mechanism or spindle — a standard part, minutes to swap.
- Sash dropped, catching the frame, draughts at one corner: Worn friction hinges. New hinge pairs restore the seal and the smooth close — and cure most "draughty window" complaints without any glazing work.
- Window won't lock / key turns without locking: The multipoint mechanism or gearbox. Repairable on almost all systems — and worth doing promptly, since an unlockable window is an insurance problem as well as a security one.
- Draughts all round: Perished gaskets and seals — replaceable by the metre for modest money.
When replacement really is the better call
- Rotten or distorted frames: A failed frame (rot in timber, warped or cracked uPVC) can't be economically repaired — that's a genuine replacement window job.
- Single glazing: There's nothing to repair back to — upgrading is an efficiency decision, and double vs triple glazing covers the options.
- Repeated unit failures across the house: If units keep blowing every couple of years, the original installation quality is the issue — patching one unit at a time becomes a subscription.
- Security upgrades: Very old windows without modern locking may be worth replacing outright rather than retrofitting piece by piece.
Briefing a repairer properly: Photograph the problem, note the window's age and (for units) measure the visible glass width and height. Ask whether the quote covers unit, labour and new seals together — and for misted units, ask about upgraded glass (acoustic, solar-control) while the unit's out anyway: the labour is already paid for. Choosing who does the work matters as much as the price — our installer-vetting guide applies to repairers too.
The bottom line
Before accepting a windows quote in the thousands, price the repair: £85 for the misted unit, £45 for the handle, £150 for hinges — the maths favours repair in the great majority of cases, and the exceptions (failed frames, serial unit failures) announce themselves clearly. Find vetted window repairers and glaziers near you here.
Frequently asked questions
Yes — condensation between the panes means the sealed glass unit has failed, and the unit alone can be swapped within your existing frame for around £55–£180 (large units up to £400), against roughly £450 for a whole new window. The frame itself rarely needs replacing.
Typically £50–£350 per window in 2026: handles from about £30, hinges around £50–£150, locks and uPVC mechanisms £50–£250, and misted unit replacement £55–£180. Replacing all blown units in a 3-bed semi usually costs £1,400–£2,500 — far below whole-house window replacement.
Usually worn friction hinges letting the sash drop out of alignment, or perished gaskets. Both are standard repairs — new hinge pairs restore the seal and smooth closing, and gaskets are replaceable by the metre — no new window required.
When the frame itself has failed (rot, warping, cracks), when the windows are single glazed, when sealed units keep failing repeatedly across the house — pointing to poor original installation — or when very old windows lack modern security. Component faults on a sound frame almost always favour repair.