How Much Does It Cost to Replace Blown Windows?

For a 200mm x 400mm blown window, the average cost of a replacement is £30 to £60 for one unit, £60 to £110 for two windows, £95 to £155 for three windows, or £135 to £195 for four windows.

In the case of a 500mm x 700mm window, the cost of replacing blown windows is about £45 to £80 for a single window, £90 to £145 for two windows, £145 to £200 for three windows, or £215 to £275 to replace four windows.

As for an 800mm x 1000mm window, if it is blown, the blown window replacement cost would land around £85 to £125 for one unit, £180 to £240 for two units, £280 to £350 to replace three units or £380 to £460 for four replacements.

man measuring a window frame

Lastly, if a large 900mm x 1200mm window has misted up, you'll need to budget for about £120 to £150 to replace one unit, £250 to £300 for two windows, £385 to £425 for three windows, or £505 to £565 to have four windows replaced.

Other cost factors are the type of windows being replaced, the number of window fitters hired, ease of access, and your property's location.

Window fitters tend to charge higher rates in the southeast and London especially, while rates are generally below the national average in regions like northern England, Scotland, and Northern Ireland.

Blown Window Repair Prices

Size of Window No. of Windows Labour Cost Supply Costs Total Cost
200mm x 400mm 1 £10 to £30 £20 to £30 £30 to £60
2 £20 to £50 £40 to £60 £60 to £110
3 £30 to £70 £65 to £85 £95 to £155
4 £45 to £85 £90 to £110 £135 to £195
500mm x 700mm 1 £15 to £40 £30 to £40 £45 to £80
2 £30 to £70 £60 to £75 £90 to £145
3 £50 to £90 £95 to £110 £145 to £200
4 £90 to £130 £125 to £145 £215 to £275
800mm x 1000mm 1 £20 to £45 £65 to £80 £85 to £125
2 £50 to £80 £130 to £160 £180 to £240
3 £80 to £115 £200 to £235 £280 to £350
4 £110 to £150 £270 to £310 £380 to £460
900mm x 1200mm 1 £30 to £50 £90 to £100 £120 to £150
2 £70 to £100 £180 to £200 £250 to £300
3 £110 to £130 £275 to £295 £385 to £425
4 £140 to £180 £365 to £385 £505 to £565
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What are the Supply Costs of a Blown Window Replacement?

The supply costs of replacing blown windows exclude the labour cost and any waste removal expenses.

On average, the supply costs will account for about 50% of the overall cost, with around 30-50% attributable to labour expenses and roughly 10% for waste removal. Let's look at the supply costs for the jobs discussed in the previous section.

The material cost of replacing a 200mm x 400mm unit is £20 to £30. For two of these units, expect to pay £40 to £60, for three about £65 to £85, or in the case of four 200mm x 400mm replacement windows, £90 to £110.

window exterior

The supply costs will be approximately £30 to £40 to have a single 500mm x 700mm window replaced, £60 to £75 to replace two units, £95 to £110 for three replacements, or £125 to £145 to replace four of these medium windows.

To have an 800mm x 1000mm blown window replaced would come with a supply cost of about £65 to £80 for one unit, £130 to £160 for two units, £200 to £235 for three units, or £270 to £310 to have four windows of this size replaced.

It costs about £90 to £100 in supply expenses to replace a single 900mm x 1200mm window. For two of these units to be replaced, expect to pay £180 to £200, for three units, £275 to £295, or in the case of four units £365 to £385.

Size of Window No. of Windows Total Cost
200mm x 400mm 1 £20 to £30
2 £40 to £60
3 £65 to £85
4 £90 to £110
500mm x 700mm 1 £30 to £40
2 £60 to £75
3 £95 to £110
4 £125 to £145
800mm x 1000mm 1 £65 to £80
2 £130 to £160
3 £200 to £235
4 £270 to £310
900mm x 1200mm 1 £90 to £100
2 £180 to £200
3 £275 to £295
4 £365 to £385

What are the Additional Costs of Blown Window Repairs?

There are several added costs you may incur as part of this work. In this section, we'll break down some recurring examples.

Minimum Fee

Some window fitters will charge a minimum fee, regardless of how much work is required. This may be a fee that is added to all other costs or in the form of an inclusive cost such as a daily labour charge.

In this case, a set labour charge would apply even if the work doesn't end up lasting for a full day. For instance, work that lasts for five hours may be charged as if it were a full day's work.

Type of Window

Another important consideration in shaping blown window repairs prices is the type of window you are looking to have installed as a replacement. In terms of design, casement and flush windows are among the cheapest choices.

Tilt & turn and sash window designs have a closer to average window cost, while cottage and bay windows are more expensive options.

window seat

Of course, when it comes to the number of glass panes, single-glazed windows are more affordable than double glazing, which in turn is cheaper than triple glazing.

As for the frame type, uPVC framed windows are generally the cheapest option. Timber-framed windows are roughly a mid-range option in terms of price tag, with aluminium-framed windows generally costing more than most.

Size of Property

Property size is relevant since it can directly impact the number of windows that may need to be replaced and often the size of the windows too.

Number of Window Fitters

Fixing blown windows is generally considered a one-person job, unless for a particularly large window.

However, should two or more contractors be hired, your hourly or daily labour cost will increase as a result.

Of course, the more workers on the job, the quicker the work will be, so whether this increased hourly or daily labour cost will actually increase the cost overall is difficult to say.

It will largely depend on how effectively a team of window fitters work in unison.

Duration

The longer the work lasts, the more the labour costs will likely come to. The only exception to this rule may be in a scenario where a daily labour cost or fixed-job cost applies, and a four-hour job turns into a six-hour job.

Otherwise, the length of the work will be one of, and in some cases, the most important cost factor.

Tradesmen Costs for Replacing Blown Windows

The labour cost is how much you pay a tradesperson or a team of tradespeople on an hourly or daily basis for their work.

In this section, we'll lay out the labour costs involved for the various window replacement jobs discussed in the opening section.

For the following costs, we are assuming that a single labourer has been employed for these tasks. If two labourers are hired, double the costs for an approximation of a two-person labour charge.

Notably, there is a reasonable chance that two window fitters will be employed for fitting a large window. Please note that the labour cost is often also shaped by the size and number of windows.

Some labourers charge in part or wholly per unit, so the hourly labour rate x duration will not translate directly into the average labour cost.

The blown windows repairs cost of labour for having a single 200mm x 400mm blown window replaced is about £10 to £30 with the cost rising to roughly £20 to £50 for two units, £30 to £70 for three units, and £45 to £85 for four units.

a man installing a window

To have a 500mm x 700mm window replaced, one unit will cost around £15 to £40, with the price being about £30 to £70 for two units, £50 to £90 for three units, or £90 to £130 for four units.

Moving on to an 800mm x 1000mm window, the labour cost per unit is roughly £20 to £45 with two units having a labour cost of £50 to £80, three costing about £80 to £115, and four costing roughly £110 to £150.

To replace 900mm x 1200mm blown windows, one unit would have a labour fee of about £30 to £50, with two units costing £70 to £100, three units coming with a cost of £110 to £130, and the labour price being around £140 to £180 for four units.

A window fitter will charge about £10 per hour as a base labour cost, but as mentioned, the labour cost of these jobs is also influenced by the size and number of windows.

The labour cost can also be shaped by the number of tradespeople on the job, ease of access, the location of your property, and of course, duration.

How Long Does It Take to Replace Blown Windows?

The time frame involved in replacing blown windows will depend on a variety of factors. Let's take a look at how long the jobs discussed in this article might take as well as the various time-affecting factors.

For a single window fitter, it should take about an hour to replace a 200mm x 400mm window, an hour and 20 minutes to replace a 500mm x 700mm unit, 1.5 hours to replace an 800mm x 1000mm unit, or an hour and forty minutes to replace a large, 900mm x 1200mm unit.

man repairing a window

However, large windows are often replaced by two window fitters, in which case the job should take a little under an hour.

The time it takes to replace blown windows depends on the size, type and number of windows, the number of window fitters hired, ease of access, and whether or not additional work is required.

FAQs

Q: Why have my double glazed windows blown?

A: There are several common reasons why even these two paned windows can mist up over time. Firstly, blown windows double glazing may be the result of an incorrect or poor installation.

On the other hand, wear and tear, or faulty or broken seals, could be behind the issue or at least be one of the causes.

Weather can affect windows and cause them to lose clarity. You can hire a professional to repair blown double glazed windows for a reasonable price.

Q: What is the main cause of a blown window?

A: In most cases, a blown window is the result of wear and tear, but a poor fitting is another possible explanation.

Q: What are the best frame materials for replacing a blown window?

A: Timber is still considered the best option by many homeowners due to its aesthetic qualities and ability to keep heat in.

However, vinyl, aluminium, and fibreglass each have their own benefits, and the best option for you will depend on your preferences.

Q: How long before a window starts to mist up?

A: It should be about 15 years or more before a window may start to mist up, but it will depend on the quality of the window and how well it is maintained.

Q: What are the issues associated with blown windows?

A: Firstly, they are not as clear and therefore are not as aesthetically pleasing. More importantly, their heat and sound insulation qualities are lower.


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Sources

  1. https://www.cloudy2clearwindows.co.uk/news/double-glazing-become-cloudy/
  2. https://superiorwindowcompany.com/whats-the-best-window-frame-material/
Author: Dean M

I have a Bachelor's Degree in Creative Digital Media, I'm a freelance writer and I've worked for clients such as the British Blockchain Association and I have experience in writing articles, YouTube video scripts, online guides and newsletters. I have written and produced many short films as well as a web series and feature film. I am also currently working on a novel.