When something goes wrong with your double glazing, the instinct is often to assume you need new windows. But in reality, the vast majority of double glazing problems can be repaired — saving you hundreds or even thousands of pounds compared to full replacement.
What Can Be Repaired
If the window or door frame is structurally sound, most component failures are repairable:
- • Misted or failed sealed units: The glass unit is replaced within the existing frame (£60–£120 per unit)
- • Broken or stiff handles: Replaced with matching or upgraded handles (£30–£60)
- • Worn or seized hinges: Friction stays and casement hinges are replaced (£50–£90 per pair)
- • Faulty locks: Espagnolette locks, shootbolt locks, and multipoint mechanisms can be repaired or replaced
- • Degraded rubber seals: Gaskets and weatherseals are replaced to stop draughts and water ingress
- • Dropped doors: UPVC and composite doors can be re-aligned by adjusting hinges and keeps
What Genuinely Needs Replacing
Full window or door replacement is the right choice when:
- • Frames are cracked, warped, or structurally compromised
- • UPVC is severely discoloured and can't be cleaned or restored
- • Multiple components have failed simultaneously — at a certain point, individual repairs become more expensive than replacement
- • Windows are 25+ years old and no longer provide adequate insulation or security
- • You want to upgrade to more energy-efficient glass, better security features, or a different style
Cost Comparison: Repair vs Replace
The cost difference can be significant. For a typical 3-bedroom semi-detached house:
- • Repairing 4 misted units + 2 handles: approximately £400–£600
- • Replacing all windows: approximately £3,000–£6,000
If the frames are sound, repair extends their life by 10–15 years at a fraction of the replacement cost. That said, if your windows are at end-of-life, investing in modern replacements delivers better energy efficiency, security, and long-term value.
The Environmental Perspective
Repairing rather than replacing also has environmental benefits. Manufacturing new UPVC windows uses significant energy and resources. By repairing what you have, you keep functional frames out of landfill and reduce your carbon footprint. However, if replacement is genuinely needed, modern windows are significantly more energy-efficient — so the long-term environmental benefit of better insulation can outweigh the manufacturing impact.
Our Approach
At Restoration Glazing, we offer both repair and replacement services. We don't have a vested interest in pushing you towards either option — we'll assess your windows honestly and recommend whatever makes the most sense for your home and budget. Every assessment is free, and every quote comes with no obligation.
Frequently Asked Questions
What double glazing problems can be repaired?
Most individual component failures: misted units, broken handles, worn hinges, faulty locks, degraded seals, and draughty frames. If the frame is structurally sound, repair is almost always possible.
When does double glazing need replacing?
When frames are cracked, warped, or severely discoloured, when multiple components have failed, or when windows are 25+ years old and no longer energy-efficient.
Is repairing double glazing worth it?
Yes, in most cases. A sealed unit replacement costs £60–£120 vs £350–£800 for a full window. Repair extends window life by 10–15 years.
How do I know if I need repair or replacement?
We offer free assessments. If frames are sound and only 1–2 components have failed, repair is right. If frames are damaged or multiple failures exist, replacement may be more cost-effective.