Window Glass Replacement Cost
- The average cost of replacing blown windows is around £70.
- Double glazing glass replacement typically takes 1 hour.
- A breakdown of how much misted window repair costs for different-sized units.
- An overview of what the job involves and expert advice from tradespeople on MyJobQuote.
- How to find a local window repair specialist..

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Table of Contents
- How Much to Replace Double Glazing Glass?
- How Long Does Window Glass Replacement Take?
- What Causes Blown Windows?
- What Affects the Cost of Replacement Double Glazed Units?
- What Extra Costs Are Connected With Blown Windows?
- Can You Replace Window Glass in Double Glazing Yourself?
- 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 2025?
Replacing blown double glazed windows can often seem like an expense you could well do without. But if the problem is simply misted up or cloudy double glazing, then you don't have to replace the entire window — just the double glazed unit itself.
Repairing a blown double glazed window is a common and affordable job that window fitters deal with. The average window glass replacement cost is between £55 and £195, 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?
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.
| 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 | £117 |
| 900mm x 1200mm unit | £95 | £50 | £145 |
How Long Does Window Glass Replacement Take?
The table below provides an estimate of how long it typically takes a specialist to make double glazing repairs like this.
In short? It should not take an experienced tradesperson more than about an hour to correctly replace the glass in a double glazed window.
| 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 |
What Causes Blown Windows?
How do glazed windows become blown? Below we take a look at some of most common scenarios:
- Poor window installation - Without being fitted correctly to start with, there are going to be further issues later on.
- Failed seal - If the seal between the two panes of glass breaks, it allows moisture and condensation into the gap.
- Older windows - When exposed to the elements, frames and sealant can deteriorate over time.
- Weak or low-quality glass - Using materials that are easily damaged are likely to compromise the end quality.
- Accidental damage - If the glass or frame cracks the seal can become disturbed and no longer working effectively.
- Using harsh abrasive chemicals - Improper use of cleaning materials or chemicals can result in damage to the seal and frame.
How long do you expect double glazing to last before problems occur?
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.
Here are some examples:
Number of Panes
If there is only one pane with misty windows then this will be cheaper to repair in terms of materials compared to the cost of replacing multiple units.
However, bear in mind that the labour costs may not be too dissimilar if you have a small job to do. This is because the glazier cost will include any set-up time, plus they may have a minimum fee to ensure they're paid fairly for their work.
Size and Style
Larger windows will be more expensive when you're looking at a home window repair, simply because they require more materials and more work.
It's also worth noting that some window styles like bay windows generally have more glass so these will be pricier.
Type of Glazing
Double glazing is common in the UK, and so many quotes on glass replacement will default to this type of glazing. Yet triple glazing is also becoming popular and the costs of blown window replacements will be higher because there's more glass involved.
Similarly, rooms like bathrooms often use frosted glass for privacy, with the cost of this glazing style generally higher.
If there's something extra added to your windows such as self-cleaning technology or tinting, you can expect the replacement window glass to be more expensive.
Material Costs
This links with the factors above and the cost of glass is a major element of any window repair.
However, it's also important to recognise the smaller material costs that might go into the job such as any work on the actual window frame itself.
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 invariably 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?
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
Although many replacement double glazed units will not require frame replacement, there are some instances where it might.
If the window frame is damaged, it may make more financial sense to replace it at the same time as the blown window. This may only be recognised when the window unit itself is removed, so it can be something of a hidden cost through no fault of your contractor's.
Trims
The cost of new finishing trims for your windows will usually be included in the quote for double glazing glass replacement, but it's worth checking as it improves the overall aesthetic appeal of the windows.
Security Features
Checking whether your window handles are still effective is another quick task that could be useful when you're making any changes to your windows.
Replacement handles could improve the security of your home, as well as resolving any issues you might have had with opening and closing the units.
Waste Disposal
Typically, the disposal of old window units is included in your home window repair quote. However, always check with your contractor that they plan on taking the old window away with them or you will need to arrange disposal yourself.
Can You Replace Window Glass in Double Glazing Yourself?
In theory, with the right set of skills, removing a blown double-glazed unit in order to replace a uPVC window is relatively straightforward.
However, attempting the job yourself could void any existing warranties. Poorly fitted windows may also affect performance and could impact your home insurance in the event of an emergency. By hiring a professional, you not only ensure the job is done correctly, but you also avoid unnecessary stress and benefit from their guarantees.
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 glass, whether it’s toughened, and the type of glazing used. While ordering the glass yourself might save money, most installers will include the cost of the glass in their overall quote.
What’s the Process of Repairing It?
One of the most common reasons why double glazed units become misty is because the seal between the two panes of glass has failed.
If this happens, then you do not need to replace the entire window including the frame.
You can, in fact, simply replace the double glazed unit itself. Alternatively, there are specialist companies that can repair the double glazed units by removing any moisture and resealing the window.
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?
Is Replacing a Glazed Unit Complicated?
Replacing a double glazed unit is fairly straightforward and in fact, any local handyman or DIY enthusiast should be able to do it.
However, the difficult part and the part which can often lead to expensive mistakes is the initial measuring of the window before placing an order with a manufacturer.
Any mistakes in these initial measurements can result in a brand-new double glazed unit which simply will not fit properly into the existing window frame.
Blown Double Glazing Checklist
- Does the contractor offer any guarantees on the replacement glass and installation?
- How much is the total cost? Ask for a breakdown so you know exactly what you're paying for
- Is the contractor experienced in repairing and replacing blown glass?
- Will the contractor take all the necessary measurements themselves?
- Do they take the required measurements as part of the service?
- Will the contractor remove any left-over waste or the old window?
- Is your contractor insured to carry out the work?


