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myWindow Glass Replacement Cost
At a Glance
- The average cost of replacing blown windows is around £70.
- Double glazing glass replacement typically takes 30 to 60 minutes.
- A breakdown of how much misted window repair costs for different-sized units.
- A simple calculator for you to quickly estimate window glass replacement costs.
- An overview of what the job involves and advice from tradespeople on MyJobQuote.
- How to find a local window repairer.
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£70
Table of Contents
- How Much to Replace Double Glazing Glass?
- How Long Does Window Glass Replacement Take?
- What Affects the Cost of Replacement Double-Glazed Units?
- What Extra Costs Are Connected with Blown Windows?
- What Causes Blown Windows?
- How to Tell if You Need New Glass or a Full Window Replacement
- What's Involved in Replacing a Sealed Window Unit?
- Blown Double Glazing Checklist
- FAQs
How Much to Replace Double Glazing Glass?
Struggling with misted or blown double glazing? Need to know how much window glass replacement costs in 2026?
Replacing blown double-glazed windows can often seem like an expense you could do without.
But, if the problem is simply misted up or cloudy double glazing, then you don't have to replace the entire window, only the double-glazed unit itself, known as the "sealed unit", which is a cost-effective solution.
What exactly is a sealed unit?
Simply put, this is the glass component of your window, not including your window frame. Double or triple glazing is made up of two layers of window glass (three for triple), a spacer bar, and an airtight seal between the panes of window glass.
So, when a window is "blown", this means...
- The airtight seal has been compromised.
- Moisture has got between the panes of window glass.
- There's persistent condensation, misting, or a generally cloudy appearance coming from within the window.
Repairing a blown double-glazed window is a common and affordable job that window fitters deal with. The average double or triple glazing replacement cost is between £55 and £220, but the exact price you're quoted will mainly depend on the size of the window.
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How much does it cost to replace blown double-glazed units in a typical two-bedroom terraced house?
"It depends on the size of the unit, but a normal-sized window costs about £50."
Window Glass Replacement Prices
In the table below, you'll find an overview of how much misted window repair costs for different-sized double-glazed windows.
To identify your window size, here are some rough comparisons:
- Small Bathroom/Utility Room Window — 200mm x 400mm unit.
- Standard Small-Size Window — 500mm x 700mm unit.
- Standard Medium-Size Window — 800mm x 1000mm unit.
- Standard Large-Size Window — 900mm x 1200mm unit.
| Window Size | Material Cost | Labour Cost | Total Cost |
|---|---|---|---|
| 200mm x 400mm unit | £25 | £30 | £55 |
| 500mm x 700mm unit | £34 | £40 | £74 |
| 800mm x 1000mm unit | £72 | £45 | £115 |
| 900mm x 1200mm unit | £95 | £50 | £145 |
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Window Glass Replacement Costs by Glass Type
When it comes to the cost of replacing your sealed unit, usually the biggest factor influencing the price of the window replacement will be the size. However, the type of sealed unit you need to replace will also have an impact on the final cost.
If you're replacing triple-glazed units, or units with toughened or energy-efficient window glass, then these are likely to cost more than a standard double-glazed unit. The table below shows typical costs for different types of replacement glass for uPVC windows.
| Window Glass Type | Typical Total Cost |
|---|---|
| Standard double-glazed unit | £55–£145 |
| Triple-glazed unit | £90–£220 |
| Toughened double-glazed unit | £80–£180 |
| Frosted or obscure double-glazed unit | £70–£170 |
| High-performance energy-efficient unit | £80–£190 |
| Conservatory side panel unit | £120–£250 |
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Conservatory window glass replacement is often more expensive simply because these panels are often much larger than standard house windows. Plus, additional features such as being toughened or having tinted glass may also be required.
Estimate Your Costs to Replace Window Glass
Looking for a project-specific cost for your window glass replacement?
If you're not sure what local prices will look like in your area, why not try out our free replacement window glass cost calculator!
Simply fill in a few details, and get an accurate idea of local replacement glass costs in your area.
Window Glass Replacement Cost Calculator
How Long Does Window Glass Replacement Take?
An experienced tradesperson will take around 30 to 60 minutes to correctly replace window glass in a double-glazed window.
As you can see from the table below, larger units will naturally take longer to replace. It's also worth mentioning that it would be more efficient to have multiple units replaced in the same visit, as travel and setup time will be spread across a single, larger job.
| Window Size | Estimated Duration |
|---|---|
| 200mm x 400mm unit | 30 mins |
| 500mm x 700mm unit | 40 mins |
| 800mm x 1000mm unit | 45 mins |
| 900mm x 1200mm unit | 50 mins |
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What Affects the Cost of Replacement Double-Glazed Units?
There are various factors that will affect the window replacement cost if you have blown windows:
Number of Panes
Replacing one sealed unit with misty windows will be cheaper in terms of materials compared to the cost of replacing multiple units.
However, bear in mind that with call-out charges and minimum fees, the labour costs may not be too dissimilar if you only have a small job to do.
Size and Style
Replacing larger home windows will be more expensive, simply because they require more materials and more work.
It's also worth noting that repairing window styles with more glass, like replacing bay windows, will also be pricier.
Type of Glazing
Double glazing tends to be the most common type of blown window repair, but triple-glazed windows cost more to replace due to more materials and a more complex construction.
Similarly, frosted windows like those found in bathrooms, or anything special like self-cleaning or energy-efficient coatings, safety glass, or tinting, will make the glass replacement more expensive.
Window Frame Condition
Your window frame itself may generally be in good condition, but beads, seals, or other components may need to be repaired or replaced along with the window glass.
If any of the pieces that keep the glazing unit in place need replacing or get damaged when the glass is removed, this will affect the cost of the job.
Access Challenges
It should be relatively easy to replace window glass in standard height, ground floor windows.
However, upstairs windows or windows that are difficult to get to may require additional labour and access equipment, increasing the cost of the job.
Location
Finally, where you are in the UK will affect the prices you pay for window glass replacement.
Households in London and the South East will typically pay more for this type of work due to the higher cost of living in those areas.
The top pane in my window is blown but the lower one looks fine. Do I need to replace the whole lot?
"No you don't need to replace the lot, just the one that has blown.
Only the glass will need to be replaced. It's worth taking a look at your other windows just in case — but unless it's really noticeable, it's not necessary."
Only the glass will need to be replaced. It's worth taking a look at your other windows just in case — but unless it's really noticeable, it's not necessary."
What Extra Costs Are Connected with Blown Windows?
There are some additional costs that might be involved with window pane replacement.
These will depend on your window's condition, and what type of agreement you have with your contractor:
Replacement Window Frame
In most cases it might be possible to simply replace the glass in your windows, but if the frame is clearly damaged, or damage is found once the glass is removed, it might be necessary to replace the whole window.
Depending on the type and size of new window you need, you could expect additional costs of between £300 and £700 for a standard uPVC window.
Glazing Beads, Gaskets and Seals
You can usually remove the beads and seals around your window glass, fit the new glass, and then fit everything back into place. But if they are damaged, get damaged during removal, or perhaps just look tired, you might want to replace them.
If these will be an additional cost, they are not very expensive, typically between £10 and £30 depending on type and size.
Glass Upgrades
While you're replacing your glazing unit you might also take the opportunity to upgrade the glass in your windows.
Replacing standard double glazing with energy-efficient, toughened, or self-cleaning glass will cost around £15 to £60 more per typical unit.
Access Equipment
If your windows are hard to get to or heavy and awkward to handle, you might need to budget for the additional cost of some kind of scaffolding or hydraulic lift equipment.
Hiring a small access tower to replace window glass could cost £100 to £300, but more specialist access equipment or scaffolding could add an extra £300 to £1,000+ to your costs.
Waste Disposal
Typically, the disposal of old window units is included in your home window repair quote, but always check with your contractor.
If you need to arrange to get rid of your old sealed units yourself, expect to pay between £20 and £50 to have them properly disposed of.
What Causes Blown Windows?
How do glazed windows become blown?
Let's take a look at some of the most common scenarios:
- Poor Window Installation — If windows aren't fitted correctly to start with, there are going to be further issues later on.
- Failed Seal — If the seal between the two panes of window glass breaks, it allows moisture and condensation into the gap.
- Older Windows — When exposed to the elements, frames and sealant can deteriorate over time.
- Accidental Damage — If the glass or frame cracks, the seal can become disturbed and no longer work effectively.
- Using Harsh Abrasive Chemicals — Improper use of cleaning materials or chemicals can result in damage to the seal and frame.
While there can be a number of different explanations why double pane glass units fail and become misty, the fact that the seal between the two panes of glass has failed is usually the most common reason.
Two of our windows have misted up between the panes. Can just the glass units be swapped rather than whole new windows, and what does that cost?
"Yes it’s a very easy change over of double glazing units. Typical sized glass units cost around £60 to 80 per unit plus labour."
How to Tell if You Need New Glass or a Full Window Replacement
Usually, with a blown double-glazed unit you should be able to simply replace the glass in the window. However, if there are problems with the frame itself, the whole window could need replacing, but how can you tell?
Signs you might just need to replace the glass unit include:
- Condensation Between the Panes — A classic sign that the seal between your double-glazed window panes has failed is condensation between them, as moisture has been able to get in.
- Obvious Localised Damage — Damage such as a cracked glazing unit where the rest of the frame looks fine may indicate that a simple glass replacement is required.
- No Obvious Frame Issues — If there is no obvious damage to the frame and it still opens and closes without problems, you probably only need to replace the damaged glass.
If you're experiencing any of the following, you might need to replace the whole window, as simply replacing the glass is unlikely to improve the window's performance:
- Clear Damage or Deterioration — If there is obvious damage or deterioration to the frame it's likely that the complete window will need replacing.
- Issues Opening and Closing — If the frame prevents the window from opening and closing properly, it could be warped or damaged and needs replacing.
- Draughts and Water Leaks — Significant draughts and water leaks round the edges of the window or frame are signs that a new window could be required.
In general, if the issues are localised to the glazing unit itself, you might be able to simply replace this and restore your window. But if the frame itself is also causing issues, then it's likely that a full window replacement could be needed.
How long do you expect double glazing to last before problems occur?
5 years or less
41 votes - 8%8% of votes
6 – 10 years
79 votes - 16%16% of votes
11 – 15 years
117 votes - 24%24% of votes
16 – 20 years
116 votes - 24%24% of votes
More than 20 years
130 votes - 27%27% of votes
483 votes
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What's Involved in Replacing a Sealed Window Unit?
Replacing a sealed unit is a relatively straightforward project, but a successful installation requires accurate measurements to be taken.
For the best results, we recommend hiring a local window repair specialist to get the job done efficiently and correctly.
The easiest way to find a glazier near you is to use MyJobQuote. By entering a few details about your job, location, and budget, you'll be matched with local traders ready to help you with your misted windows.
It's free, easy, and there's no obligation to book.
This is what you can expect the process to look like when you hire a professional to replace window glass in your home:
Before the Job Starts
- Inspection & Measuring — Your window specialist will confirm the sealed unit has failed, check the condition of the existing frame, and take accurate measurements for your window glass replacement.
During the Job
- Removing the Old Unit — The glazing beads are removed, the failed unit is taken out, and the frame is prepared for the new unit.
- Installing the Replacement Unit — The new sealed unit is fitted, the glazing beads are reinstalled, and the window is checked to make sure it operates correctly.
After the Job
- Final Checks & Clean Up — The new unit is checked to make sure it is fitted securely with no movement or gaps, the work area is tidied, and the old sealed unit is taken away to be disposed of properly.
My mum’s bungalow has four double glazed windows with condensation between the panes. Is there a way to remove the condensation, or do the windows need to be replaced?
"The glass units have blown. It’s only a small job to replace the glass — there’s no need to replace the entire window. Replacing four units should take around an hour."
Blown Double Glazing Checklist
Before choosing a window repair specialist, here are the things you need to consider to make sure you find the best trader for your job:
- Have you been sent an itemised cost breakdown? Always ask for a breakdown so you know exactly what you're paying for.
- Does the contractor have experience with blown window replacement? Make sure the contractor is experienced in repairing and replacing blown glass for best results.
- Is waste removal included in the quote? Check to see if the contractor will remove any leftover waste or the old window, or if it's an extra cost you need to budget for.
- Is there a guarantee or warranty on their work? Before booking, ask if the contractor offers any guarantees on the window replacement and installation.
- Does the contractor have insurance? Make sure they're insured to carry out the work, ideally with Public Liability Insurance.
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FAQs
How Long Should My Windows Last Before They Start Misting Up?
Double-glazed windows should last for 20 to 35 years or longer if they are good quality, well-maintained, and installed properly. This lifespan is for the entire window, not just the sealed unit, so they may start to mist up sooner than this. It depends on the quality of the installation and window.
Is Resealing a Window a Good Idea for Blown Double Glazing?
It's recommended you opt for a replacement unit rather than resealing a blown window. This is because window glass repairs will often simply remove the visible signs of the problem (e.g., cloudy windows) but may not fix the problem fully, leading to more problems later.
Does a Blown Sealed Unit Affect a Window's Energy Efficiency?
When a sealed unit is blown, it means the seal between the glass panes has failed and the insulating gas between them may escape. As a result, the unit may not insulate as effectively as it used to. How noticeable this is depends on the size of the window. A single unit in a multi-unit window might not make much difference, but a large blown conservatory sealed unit might be a different story.
Can I Replace a Blown Sealed Unit Myself?
With the right set of skills, removing a blown double-glazed unit can be relatively straightforward. If you're ordering a replacement unit directly from a supplier, you'll need to know precise details such as the size and thickness of the window glass, whether it's toughened, and the type of glazing used.
If your window also has issues with the frame and you need to replace a uPVC window, this may become more than a DIY job and something you want to hire a professional for to make sure it is done properly.
Is a Blown Window Covered by Insurance?
You'll need to review your home's insurance policy to see if this is the case. In general, insurance companies won't pay out if it's just the seal that's broken, whereas if it's the window glass, then it may depend on what has caused the issue.
Does a Blown Window Repair Come with a Warranty?
Your new sealed unit will probably come with a manufacturer's warranty, which will differ from one manufacturer to another, and your installer may also offer a warranty or guarantee on their workmanship. Check with the professional you hire. Similarly, if you end up replacing your whole window, you will probably get a warranty for the new window and the installation, but these will also vary.
