Misted double glazing: Repair vs replace and typical UK costs
- 24 November 2025
- News
If your windows have started looking misty, it’s more than just a little cosmetic issue.
Misted double glazing usually happens when the sealed unit trapping air between glass panes fails. This lets moisture in, creating condensation that reduces energy efficiency, increases heat loss, and can make rooms feel colder.
For homeowners in Buckinghamshire, Bedfordshire, and Northamptonshire, it’s of course important to properly understand the costs of misted double glazing repairs, before deciding whether to repair or replace your windows.
With over 20 years’ experience, we at Crown Conservatories, Windows and Doors Ltd help homeowners weight up their options and take prompt action before further damage occurs.
Do My Windows Need Repairing or Replacing?
When a seal fails, the window unit can often be repaired, but not always. The right solution depends on the level of damage, age of the window, and how well your existing frame is performing. Acting quickly can prevent further issues such as increased heat loss, higher energy bills, or even structural problems in older windows.
Signs Your Windows Can Be Repaired
Not every misted window needs a full replacement. Some common issues can be addressed effectively without a full window swap.
Minor Seal Failure
If condensation is only forming in one small section between the panes, your window may be suitable for repair rather than full replacement.
Small Cracks in the Glass Unit
Tiny cracks that haven’t spread widely can sometimes be repaired by removing the affected seal and refilling the unit with moisture-absorbing materials.
Existing Misting Is Minimal
Windows with light, patchy misting or that only occasionally fog up in colder weather may respond well to a restoration service, improving clarity and thermal performance without replacing the entire window.
Good Condition Frame
If your window frames are still in good condition, no rot, warping, or damage, repairing the glass unit can be a great option and more cost-effective than full replacement.
Window Repair Cost Insights: Depending on the type of glass and number of windows, repairs typically range from £80 to £250 per unit, making this a practical solution for minor issues.
Signs Your Windows Need to Be Replaced
Some signs indicate that your double glazing is a lost cause and replacement is in your best interest. Acting quickly can prevent higher energy expenses and maintain home comfort.
Widespread Seal Failure
If the misting covers entire glass panes, the seal has failed completely. This level of damage usually means the window can no longer maintain thermal performance.
Older Windows
Units over 15 years old may have outdated materials or worn frames. Repairing them might be a short-term fix, but replacement ensures long-term energy efficiency.
Warping or Frame Damage
Wooden or uPVC frames that are warped, cracked, or rotting compromise the seal and can let cold air and noise in. Full replacement is usually the best solution here.
Heat Escapes and Higher Energy Bills
If your heating system is working overtime to maintain warmth, this is a key indicator that your windows are losing heat and raising energy costs.
Replacement Costs: A new double-glazed window unit varies significantly depending on material, style, and location, but starts from around £600 including installation. For multiple windows, the total cost rises, but investing in a full window replacement ensures long-term energy savings and improved comfort.
Replacement Windows From Crown
If you’re looking at full replacement, we provide a range of made-to-measure, energy-efficient options:
- Casement Windows: Versatile and classic, hinged at the side, opening outward for excellent ventilation.
- Flush Sash Windows: Traditional appearance with a sleek, flush finish for a heritage look.
- Sliding Sash Windows: Period elegance, slide vertically, ideal for period properties.
- Tilt and Turn Windows: Flexible ventilation and easy cleaning, tilt for safety, turn fully open for access.
- Georgian Windows: Decorative grids for a traditional style, perfect for older homes.
- Lead Windows: Unique, bespoke designs with leaded patterns for character and charm.
Materials:
- uPVC: Low-maintenance, thermally efficient, and cost-effective.
- Aluminium: Strong, durable, slimline profiles, suitable for modern designs.
We help homeowners choose the type of glass, including privacy, decorative, leaded, or Georgian, and can add astragal bars or specialist laminated and sound-reduction glass for acoustic comfort. Every window is made to measure for a precise fit, finished with your choice of popular colours like Anthracite Grey, classic whites, or woodgrain.
Frequently Asked Questions
How long does a misted window repair last?
Typically, repairs improve visibility and performance for 5–10 years, depending on the type of glass and local climate.
Can all double-glazed units be repaired?
No. For units with extensive seal failure, older frames, or structural damage signs full window replacement is usually a better idea.
Will replacing a single window affect my home’s energy bills?
Replacing a poorly performing window can reduce heat escapes and lower heating bills, especially in rooms with widespread seal failure.
Why are my windows misty?
Misty windows usually indicate a blown double glazing unit where layers of glass are compromised, letting moisture in and reducing thermal performance over the long run.
Can blown window panes be fixed?
Minor blown window issues can sometimes be repaired, but widespread double glazing condensation or wider gaps usually require full window replacement for lasting results.
How can I prevent future misting?
Prevention tips include avoiding chemical damage, maintaining seals, and ensuring frames are in good condition. Proper installation plays a paramount role in long-term performance.
Will noise levels improve after replacement?
Yes. Modern double glazing windows reduce external noise and sound waves, improving comfort. Laminated glass and quality seals play a vital role in lowering noise levels.
Who Are Crown?
We are Crown Conservatories, Windows and Doors Ltd, a family-run business with over 20 years’ experience, based in Milton Keynes.
We provide made-to-measure windows, doors, and conservatories across Buckinghamshire, Bedfordshire, and Northamptonshire, installed by FENSA-registered fitters with a 10-year warranty.
Our showroom showcases our wide range of uPVC and aluminium windows, doors, and conservatories.
We pride ourselves on friendly, no-obligation advice, free quotations, and exceptional customer service. Contact us today on 01908 507 778 or info@crownwindows.co.uk to arrange a free quote for misted double glazing repair or replacement.
