Replacement Glass for Windows Cost

By Sam
Last updated 7th February 2024 - Reading time: 6 mins
At a glance
  • Average cost for a garage conversion is £70
  • It will take roughly an hour to complete
In this article, you'll find the following:
  • A breakdown of pricing information for different sized windows
  • How long the job will take and a general overview of what the job entails
  • How to find and hire a window specialist

Want to know how much replacing blown windows will cost?

On average you can expect to pay between £55 to £195, depending on the size of the blown window.

What else can this guide help you with?

In this price guide, we take a look at the costs for window repair, (including repairing uPVC windows, window mist repair and replacing window panes and blown double glazing) as well as the cost of hiring a window fitter to carry out the work.

Just need a quote?

You can check out our window glazing experts for a few quotes.

Want to find out more first? Take a look below for the complete guide...

person replacing a window

Typical cost for replacing a double glazed unit is around

This type of job normally takes around 40 minutes to complete


How Much to Replace Window Glass?

Let's get started...

Replacing blown double glazed windows can often seem like an expense you could well do without.


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.

If you want brand new double glazing for all your windows, then read our new double glazing cost guide.

Can you repair a blown window yourself?

You can do this yourself as a DIY project, however, you will have to be very precise with the measuring. Most people will simply get a local joiner or window fitter and to do the job.

Would rather a professional do it? How do you find one?

A great way to find a reliable local window fitter is through recommendations from friends, family or neighbours.

But if this is not possible, then we provide a free and easy-to-use service on this website you can simply enter brief details about the job plus some contact information, then you can have up to 3 local tradesmen get in touch with you to provide written quotations.

Window Glass Replacement Prices

Job Description Duration Material Cost Labour Cost
200mm x 400mm unit 30 mins £25 £30
500mm x 700mm unit 40 mins £34 £40
800mm x 1000mm unit 45 mins £72 £45
900mm x 1200mm unit 50 mins £95 £50
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Things to Consider with Blown Double Glazed Units

How do glazed windows become blown?

The main reason why double glazed units become misty is that the seal between the two panes of glass has failed.

What's the process of repairing it?

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 even specialist companies which can repair the double glazed units by removing any moisture and resealing the window.

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 this initial measurements can result in a brand-new double glazed unit which simply will not fit properly into the existing window frame.

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Doing it Yourself

Removing blown double glazed units is normally fairly simple,  although some modern double glazed windows are fitted with special antitheft blocks which can complicate things.

The double glazed units themselves can be held in place using pressure gaskets or double sided tape, but in either case can be removed relatively easily.

Before ordering the replacement double glazed unit you will not only have to be very precise with the measurements, you will also need to know the thickness of the glass panes, whether the glass is toughened, and the type of glass for example is the glass tinted or standard.

With the right skills and tools, DIY replacement of a double glazed unit is certainly possible.

But you also have to consider that this is not a terribly expensive job and if you get a professional in then the job won't take as long, or be as messy, and will be much less hassle and frustration, and you can avoid a potentially shoddy job being done and then having to hire a professional in anyway!

Blown Double Glazing Checklist

  • Blown double glazing is much less energy-efficient so will cost you money
  • With blown double glazing you do not have to replace the entire window
  • Misted up double glazing units can also be repaired in some cases
  • Replacing a double glazing unit is fairly straightforward
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How much does it cost to replace a blown double glazed window?
Normally, this would simply involve replacing the double glazed unit itself rather than the entire window. So this, in most cases, will be a relatively cheap job, with the bulk of the costs actually being the labour.
How much does replacement sealed double glazing unit cost supply only?
You can buy double glazed units in standard sizes from as little as around £20.
How long should my windows last before they start misting up?
This really depends on the quality of the windows. Many customers report no problems with double glazing after 15 years or more. On the other hand, there are instances of blown double glazing happening within five years of installation.
What causes condensation between the panes of a double glazed window?
In most cases, this is caused by the seal around the window feeling and allowing moisture to get in between the panes. Although, there can be other reasons which mainly relate to any building work going on in the immediate vicinity of the window.
As replacement the only option with blonde double glazing?
No, you can also have double glazed windows repaired in situ by specialist companies. But this is not always possible and depends on the type of glass in the window frame material.
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