Roof Window Replacement Cost

Last updated 30th January, 2024

Have you been looking at replacing a roof window? Want o know more about Velux window installation?

This article covers all you need to know about fitting a Velux window. We discuss Velux window prices, labour fees and much more!

Let's get started below!

replace roof window

Ready to get a price for your job?

Get Prices

How Much Does It Cost to Replace a Roof Window?

The average cost of replacing a roof window will vary depending on the type of roof window that needs replacing. For instance, prices range from £180 to £950 for top hung roof windows, £210 to £1100 for centre-pivot windows, £390 to £940 for conservation roof windows and £270 to £2710 for fixed and non-opening roof windows.

Larger roof windows are more expensive, for example, balcony windows tend to cost around £2140 to £5460, while flat roof domes normally range from £825 to £1990. If you have walk-on roof windows that need replacing you should expect to pay anywhere from £1750 to £3630 and around £1070 to £2840 to install a roof lantern.

What will the overall cost depend on?

The cost of installing a roof window will also depend on a number of factors including the number of windows you need installing as well as the level of access to the roof and whether scaffolding is required – if so, the cost will increase. The final cost will also vary for different-sized windows along with varying types of glazing and frame materials.

Roof Window Prices

Here are a few average costs for hiring someone to replace a roof window. This price includes the labour and material costs:

Centre-Pivot Window

uPVC £250 to £860 £470 to £595 £600 to £700
Timber £290 to £450 £450 to £830 £580 to £1100
Aluminium £210 to £250 £275 to £595 £390 to £450

Top-Hung Roof Window

uPVC £490 to £910 £560 to £650 £690 to £800
Timber £370 to £540 £520 to £690 £720 to £950
Aluminium £180 to £440 £495 to £565 £635 to £940

Conservation Roof Window

uPVC £390 to £415 £480 to £590 £620 to £670
Timber £400 to £470 £550 to £710 £690 to £900
Aluminium £450 to £545 £570 to £730 £800 to £940

Fixed & Non-Opening

uPVC £450 to £560 £535 to £740 £630 to £2710
Timber £270 to £290 £510 to £650 £590 to £730
Aluminium £530 to £590 £590 to £780 £815 to £1000

Balcony Window

Timber £2140 to £3555 £2285 to £4885 £4060 to £5460
Aluminium £3590 to £3860 £4250 to £5200 £5130 to £5320

Flat Roof Domes

uPVC £960 to £1050 £1550 to £1715 £1920 to £1315
Aluminium £825 to £1070 £1180 to £1420 £1590 to £1990

Walk-on Roof Window

uPVC £1750 to £2000 £2140 to £2160 £2700 to £3050
Aluminium £2150 to £2480 £2640 to £2800 £3430 to £3630

Roof Lanterns

uPVC £1490 to £1670 £2160 to £2350 £2620 to £2830
Aluminium £1070 to £1190 £2170 to £2450 £2530 to £2840

Supply Costs

If you wish to purchase your own roof windows directly from the manufacturers, then the following tables will help you understand the material price for roof window types.

Centre-Pivot Window

uPVC £150 to £760 £320 to £445 £400 to £500
Timber £190 to £350 £300 to £680 £380 to £900
Aluminium £110 to £150 £125 to £170 £190 to £250

Top-Hung Roof Window

uPVC £390 to £810 £410 to £500 £490 to £600
Timber £270 to £440 £370 to £540 £520 to £750
Aluminium £80 to £340 £345 to £415 £435 to £740

Conservation Roof Window

uPVC £290 to £315 £330 to £440 £420 to £470
Timber £300 to £370 £400 to £560 £490 to £700
Aluminium £350 to £445 £420 to £580 £600 to £740

Fixed & Non-Opening

uPVC £350 to £460 £385 to £590 £430 to £2510
Timber £170 to £190 £360 to £500 £390 to £530
Aluminium £430 to £490 £440 to £630 £615 to £800

Balcony Window

Timber £1640 to £3055 £1535 to £4135 £3060 to £4460
Aluminium £3090 to £3360 £3500 to £4450 £4130 to £4320

Flat Roof Domes

uPVC £460 to £550 £800 to £965 £920 to £1215
Aluminium £325 to £570 £430 to £670 £590 to £990

Walk-On Roof Window

uPVC £1250 to £1500 £1390 to £1660 £1700 to £2050
Aluminium £1650 to £1980 £1890 to £2050 £2430 to £2630

Roof Lanterns

uPVC £990 to £1170 £1410 to £1600 £1620 to £1830
Aluminium £570 to £690 £1420 to £1700 £1530 to £1840

Additional Costs

Along with the roof window installation cost, you may also need to consider several other costs for related jobs that may need doing at the same time, including:

Broken Roof Tile Repair

Before having a new roof window installed, you may want to replace any broken tiles on your roof.

This will ensure your roof is safe and will also protect your home from leaking or damage from damp.

The cost of repairing broken roof tiles is normally around £75 if replacing less than five tiles or up to £325 for less than fifteen tiles.

Roof Replacement

If you have had your roof for more than 20 years and are starting to experience regular leaks, then your best option may be to completely replace your roof.

The overall cost of roof replacement will depend on the type of roof you want, for instance, a gable roof is normally priced at £3500 or up to £5500 for a two-valley installation.

Other options include hip roof installation which ranges from £4500 for a semi-detached home up to £5500 for a detached property, although for two valleys you can expect to pay up to £7000.

Roof Maintenance

To prolong the lifespan of your roof, you should try to have it cleaned as often as possible to prevent a build-up of debris which can cause damp.

This will also avoid flooding and will provide you with a long-lasting roof solution.

While you can clean the roof yourself, you may want to consider hiring a professional to clean and treat your roof.

This includes roof mess treatment which ranges from £500 for a small detached house up to £900 for a large detached property.

You may also to pay for a professional pressure washing service which normally costs around £600 for a small detached home or up to £1500 to pressure wash a large detached property.

Cost Breakdown Calculator

Individual costs for hiring a tradesman to install a centre-pivot roof window - Total Cost: £640






Waste Removal

Labour Costs and Time Frames

Window specialists usually charge around £100 to £200 per day to fit an average roof window and tend to work in pairs for safety reasons.

In most cases, the replacement of a roof window shouldn't take any longer than a day to complete and can often be quicker.

If you are planning to have a larger roof window installed such as a roof lantern, this may take a lot longer and can cost around £500 for a small model which takes around 2 days to install, while a large installation is normally priced at up £1000 for up to 4 days' work.

Cost Affecting Factors of Replacing a Roof Window

The cost of fitting of roof window models will depend on a considerable number of factors including:

Type of Window

There are various types of roof window which differ in price, so the model you choose will determine the final cost.

For instance, the roof window price for a low-cost option such as a top-hung roof window starts from around £180 to be installed.

However, if you want a like for like replacement for a premium balcony window, then you could end up paying around £5460.

Type of Frame

Another important element to consider is the frame material of the roof window you choose, with timber, aluminium and uPVC being the most popular options.

Prices will vary for different material and window types, for example, aluminium centre-pivot roof windows typically cost around £210 to £450, while a uPVC model is normally priced at £250 to £700, and for a timber frame, you should expect to pay around £290 to £1100.

Type of Glass

The type of glass used in your roof windows will also determine the final price, as some glass options are more expensive than others.

Roof window

For instance, single glazing is the most affordable choice which normally costs around £100 per window, while double-glazing is normally priced at £200 and over £350 for triple-glazing.

You may also pay up to £80 extra per metre for toughened glass or £40 more per square metre for laminated glass.

Size of Window

The roof window fitting cost will also depend on the dimensions of your roof opening, as the larger the window, the more expensive it will be.

For example, if you just need a small fixed roof window installed, then you should expect to pay around £450 to £590, while a large fitting could cost as much as £2710.

Location of Property

Where you live is also considerably important, as window specialists may consider the cost of petrol in their estimates, so if your home is located in a remote area, you may end up paying more.

Your location will also determine the labour rate, as Window Specialists in London tend to charge around £200 to £250 a day, while tradesman in the surrounding areas only set rates at around £100 to £150 per day.

Ease of Access

Replacing a roof window can be quite complex, especially if you have a pitched roof, as this makes the installation more difficult and may require scaffolding and other industrial equipment which could increase the cost.

However, if you are having a roof window installed on a flat surface, then costs should be kept as low as possible

What Does Replacing a Roof Window Entail?

To help you understand the process of professional roof window replacement, here is a breakdown of what you should expect:

  1. The first step of the replacement process involves laying down dust sheets in your loft to protect the floor and any personal items stored there.
  1. Once the inside of your home is protected, the window specialist will then remove the existing window, followed by measuring the exact dimensions to ensure your new window fits perfectly.
  1. They will then work with a partner to first remove the sash before installing the window frame unless it is a fixed model.
  1. Once the sash is removed, they will fix the frame onto the framing battens. When it is secure, they will secure the top corners with clips and screw in the brackets.
  1. After the frame is fitted, the sash can then be reattached by placing it back to front to ensure it is fully engaged with the frame.
  2. This will then be attached to the frame with the sash's metal arms which should fit perfectly in the top corners of the window frame along with the covers that will be clicked into place.
  1. Once everything is in place, the window installers will check that all the measurements are correct while also assessing whether the window is working as it should.
  2. After they have confirmed the quality of everything, they will then add in the last of the screws to the external corner brackets.

DIY Replacing Roof Window

Replacing a roof window for a new window of the same type and size is fairly straightforward as a DIY job, as there are no major alterations required to the roof, including no cutting of rafters if the opening is already in place and no planning permissions or building approval is required.

However, Of course, fitting a larger window will involve removing roof felt and tiles, plus cutting into rafters and adding additional support if required.

This is a much bigger project and not for the casual DIY enthusiast, so you are best calling a professional window specialist to complete the job.

Besides the complexity of a large roof window installation, there are a number of potential pitfalls to this job if doing it yourself.

Roof window replacement

For instance, even if you just need a like for like replacement, there may be a need to climb on the roof to take off tiles or flashings or to remove felt or waterproof membrane.

Before doing this, you need to ensure that there are no pipes, wires or other obstructions in the path of your roof window.

If you are lucky and your new roof window fits between the existing rafters in the existing opening, then it can be just a simple job of fitting the window to the existing woodwork, with perhaps some additional timber framework internally required for new plasterboard and decoration to finish the job off.

If you are planning to replace your roof window yourself, then you will need the following equipment:

  • Dust sheets (£2 to £16)
  • Safety tape (£0.70 to £8)
  • Screwdriver (£1 to £100)
  • Drill (£25 to £200)

Ready to get a quote from local tradesmen?

Post your job in minutes and get quotes from local and reliable trades. It's FREE. No obligations.

Get a Quote

Choosing Roof Windows

Contrary to popular belief, Velux is not a generic name for a roof window; it's the name of a specific company that makes a particular type of roof window.

However, there are actually many other types of roof windows, including:

Centre-Pivot Roof Window Cost

A centre-pivot window hinge from the middle of the frame on both sides of the roof window.

They typically cost anywhere from £110 to £900 and are suitable for roof pitches 15°, 75° and 90°.

Centre pivot roof window

The main benefit of choosing a centre-pivot roof window is that they are very easy to operate even when installed above loft furniture.

They also offer more flexibility which allows for better views of the exterior.

One of the downsides of centre-pivot windows is they are not as great to look at in comparison to other roof windows, so they may not be the best option if you are looking to improve your interior and exterior aesthetic.

Top-Hung Roof Window Cost

Top-hung roof models feature a hinge at the top of the frame which allows the window to open outwards.

They are one of the popular options when converting a loft space as they only cost around £80 to £750.

Top hung roof window

One of the key advantages of top-hung roof windows is that they have a 180° rotation which makes them much easier to clean and also offers obstructive views which is ideal if you have a lovely skyline to look at.

They are also very easy to install due to their classic design, which helps to keep installation costs down.

The problem with having a window with unobstructed views on top of your roof is that it will increase the amount of sunlight that enters you home which can cause sun damage to your interior, so you may want to purchase a blind.

Conservation Roof Window Cost

A conservation roof window is similar to a standard roof window, although it features a glazing bar down the middle of the glass pane and the window actually sits flush against the roofing material.

You should expect to pay anywhere from £290 to £740 for a replacement conservation window which is normally installed on properties in conservation areas.

Conservation roof window

You can benefit from having a conservation window installed on the roof of your home if you live in an area with historical interest that requires preservation.

The reasons for this are because a conservation roof window is designed to fit with more traditional-style properties which works much better than a modern roof window.

The downside of a conservation window is that despite them fitting in with the exterior of your home, they may not offer the most attractive aesthetic due to the middle bar.

Fixed & Non-Opening Roof Window Cost

Fixed and non-opening roof windows do not open and are only used to enhance views and increase natural light.

The average cost of fixed roof windows is around £170 to £120.

Fixed roof window

Fixed windows are one of the most energy-efficient window types as they have an extremely tight seal which prevents any heat from escaping or cold getting in.

Having this type of window installed will not only improve energy efficiency but will also reduce energy bills and lower your carbon footprint.

One of the downfalls of opting for a non-opening window is that they do not provide the ventilation that standard roof windows do, so you may want to consider combining a fixed window with a non-fixed model to improve airflow.

Balcony Roof Window Cost

Balcony windows are a more luxury option as they are usually installed alongside a balcony and railings to offer great views.

The average cost of a balcony window ranges from £1640 to £4460.

Balcony roof window

If you wish to bring the inside outside and vice versa, then a balcony window is the best option for you, as it helps to create more outdoor space just outside your loft bedroom.

It also enhances the look of your property's exterior and may even increase the value as it will stand out to potential buyers.

The main issue with balcony windows is that they are one of the expensive roof windows, so you will need to consider whether the investment is worthwhile before making any changes.

Flat Roof Domes Roof Window Cost

Flat roof domes are a type of roof light which are built with a thermoformed roof cover and are typically installed on a flat roof surface.

This type of roof window is normally priced at £325 to £1215.

Flat roof domes

This type of roof window is designed by various manufacturers who create domes that help to maximise natural light which helps to enhance the look of your space while also cutting down on electricity, as artificial light is not normally required during the day.

Due to the high level of natural sunlight, flat roof domes may actually let too much light in which can cause your home to be too warm or your interior may be susceptible to heat damage.

Walk-On Roof Window Cost

If you are lucky enough to have a roof terrace at the top of your property, you may want to consider installing walk-on roof lights which are a type of fixed window which enable you to look down to the floor below, and you can also walk on them.

For this type of roof window, you should expect to pay in the range of £1250 and £4320 for supply only.

Walk on roof window

The main benefit of walk-on roof lights is that they enhance the look of a property and make it unique, which may also help to improve the value of your home. They are also made of high-quality materials which are resistant against significant pressure and scuffing.

The downside of walk-on roof windows is that they are usually only used for decoration and therefore do not provide a good level of ventilation, so you need to make sure you have non-fixed windows in the same room.

Lantern Roof Window Cost

If you wish to spruce up your flat roof, then a roof lantern is one of the most beautiful options available.

They are normally a pyramid-style shape which mimics the look of a pitched roof, and they tend to range from £570 to £1840.

Roof lanterns

Lanterns are one of the most aesthetically-pleasing roof windows as they feature different sections which reflect light around your home.

This will not only enhance the look of your property from the inside but also the outside, which may increase the kerb appeal.

The problem with roof lanterns is that they usually have to be assembled on-site, which means labour costs will increase as the job will take a lot longer.

Choosing a Roof Window Frame

Another important choice you need to make is the type of frame material you want on your roof window.

To help you decide, here is a breakdown of the different material types, the costs and the pros and cons of each.

uPVC Window Frame Cost

One of the most popular window frame materials is uPVC which stands for unplasticised polyvinyl chloride.

This is a type of plastic which is used for a wide range of roof windows and typically costs anywhere from £150 to £2510.

The main advantage of opting for a uPVC window frame is that this material is extremely lightweight and durable.

uPVC roof window frame

uPVC also acts as a great insulator and helps to retain heat – making your home more energy-efficient.

One of the downsides of choosing uPVC is that they can often become discoloured from sunlight exposure, so you may need to replace your frame when this happens.

They also have a much shorter lifespan in comparison to timber frames.

Timber Window Frame Cost

Timber window frames are a more traditional choice and are normally used on older properties, although some modern homes also have timber frames which help to enhance character. The typical cost of timber frames for roof windows is around £170 to £4460.

The main advantage of timber frames is that they are extremely long-lasting with a lifespan of around 60 years if your windows are looked after properly.

Timber roof window frame

Timber is also a good insulator due to its low thermal conductivity which helps it to retain heat, so you do not waste money on your energy bills.

A downfall of opting for timber is if they are not maintained properly, the frame may be susceptible to broken seals and draughts which can cause damp and rot.

Timber roof window frames are also more susceptible to weather damage and can also attract insects.

Aluminium Window Frame Cost

Aluminium roof window frames are also a common option as It is a durable metal and is therefore long-lasting.

You should expect to pay around £80 to £4320 for aluminium window frames.

If you are looking for a low-maintenance window solution, then aluminium frames may be your best option as this material is extremely resistant to decay and corrosion, making it very easy to clean.

Aluminium roof window frame

It is also an extremely flexible material which can be moulded to suit different shapes, so if you are opting for a unique roof window, an aluminium frame is the best option.

One of the main disadvantages of aluminium is that it has a high thermal conductivity which basically means it does not hold heat hell, so you may lose some of the heat in your home.

This also causes condensation issues which can lead to moisture build-up and fungi-growth, which can be harmful to anyone with allergies.

Types of Glass for Roof Windows

Something else to consider the type of glass you choose for your roof windows.

There are various options to choose from, including:

Single Glazing

Single-glazing is the original type of glazing which consists of just one pane of glass which is inserted into a roof window frame.

Single-glazing usually costs around £100 or less.

Despite single-glazing not being used as often there are some advantages, for instance, single-glazing is ideal for older window frames as you only need to change the glass rather than the entire window installation.

They are also perfect for hot climates, as locations like this do not require heat retention, although if you live in England, the weather definitely does not work with this type of glazing unit.

There are various disadvantages of single-glazing, the first being the lack of insulation which will cause your home to feel cold and may even cause damp.

There are also no noise-reduction qualities due to the singular pane of glass which may be extremely annoying If you live near a busy road.


Double glazed windows are similar to single-glazed panels, although instead of one piece of glass they feature two panes of glass with a layer of inert gas in between which normally cost around £200.

The main advantage of double-glazing is the level of insulation which is formed due to the barrier of the three layers of glass and gas, which will protect your home from the elements.

It also helps to retain heat, making it extremely energy-efficient, which enables a reduction in your energy bills and carbon footprint.

One of the main issues you may experience with double-glazing is that if they have a blown seal, the glass itself cannot be fixed and will need to be replaced entirely, which can be expensive.

Triple Glazing

Triple-glazing is the latest type of glazing available which features three panes of glass with two pockets of argon or xenon gas in between.

The average cost of triple-glazing is around £350 or more depending on the size of the window.

Roof window glass

The advantages of triple-glazing are similar to double-glazing except it offers a high level of efficiency which can lower your energy bills significantly, while also providing extensive noise reduction and the glass is also much harder to break.

A downside of triple-glazing is that it reduces light penetration due to the barrier of the three panes of glass which lowers the amount of natural light and heat entering your home.

Toughened Glass

Toughened glass or tempered glass is a highly-durable glass solution which is manufactured in extremely high temperatures.

To have toughened glass installed in your roof window frames, you should expect to pay around £80 per metre.

Toughened glass is one of the most robust types of glass due to the harsh conditions it is produced, which causes its resistance to heat and shock to increase by 400 to 500%.

This results in it being extremely hard to break and also enables it to hold heat very well.

The main disadvantage of toughened glass is the extensive manufacturing process which means it can take a while to make and is also very expensive.

Laminated Glass

Laminated glass is made up of two layers of glass with a PVB plastic in between each pane of glass.

The typical cost of laminated glass is around £40 per square metre.

Similar to double-glazing, laminate glass is great for blocking out noise due to the barrier of the two panes of glass which is ideal if you live in a high-traffic area.

It also provides extensive safety, as it prevents intruders from breaking your windows and entering your home as the glass is extremely hard to smash.

A downside of laminate glass is that it is not ideal for larger or irregular-sized roof windows such as lanterns as the material is not flexible to mould to these shapes and sizes.

Building Regulations for Roof Windows

If replacing a rooflight then you do need to gain building regulations approval, however, if you are installing a roof window in a new opening, then you will usually need to apply for permission to do so.

You will have to pay to submit an application with the cost depending on your individual local authority as they all charge different rates.

Approval is typically required in the event that roof alterations need to be made along with the need for sufficient installation for your roof window.

You may also need to consider the positioning of the rooflight because if it is close to a boundary fire performance will need to be reviewed.

To meet building regulations, you must ensure that the roof is safe, the rooflight is energy efficient and feature high-quality insulation and weatherproofing materials.

You should also make sure that the room, where the rooflight is installed, is ventilated to a high standard.

Planning Permission for Roof Windows

Planning permission is not typically required if installing a skylight window as long as the alterations do not project higher or extend more than 150mm from the existing roof.

However, if you're cutting into roof timbers to accommodate your roof window, you are potentially weakening the structure of the roof.

If this is the case, so you may have to notify the planning department, which should cost around £200 for the application.

Once you have notified them, they should send out a qualified planning officer can come down and advise you on keeping the structural integrity of the roof.

Do I Need to Replace My Roof Window?

There are various signs that indicate that your roof windows need replacing, including:

Leaking Windows

One of the most common issues with roof windows is leakages which can cause significant damage to the interior of your home, which can be very expensive, so the quicker you replace your windows, the better.

Cracked Glass

You may also notice cracks on your windowpane, which usually caused by harsh weather conditions.

Roof window replacement

This could be a sign that your window is ready to break so you should replace it as soon as possible to prevent any leaks or glass breakage incidents.

Blown Window

If you notice condensation forming on the glass of your roof windows, then this is a sign that the seal is broken on the window.

At the first indication of condensation, you should replace your roof lights to prevent the condensation from damaging your roof.

Roof Removal

If you are removing tiles or removing your roof entirely, you will need to remove and replace your roof window.

You can always use the same window; however, if you have had the window for a while, you are best investing in a new one.

Removing a Roof Window Cost

In order to replace your roof window, you will need to have your existing one removed, which will cost around £150 per day when completed by a professional. You can always do it yourself.

However, if you have no experience working on a roof, then you should leave the job to the professionals as it can be a dangerous job, especially if you have a pitched roof.

Roof window removal

Most window specialists will add around £40 to the cost of the replacement to account for waste disposal.

You may also want to get rid of it yourself by taking it to the local skip yard or keep the materials for a project in the future.


If we assume a small top-hung uPVC window installation, then a typical quote would be in the region of £150, whereas a larger window will cost around £500.
This will include the window itself plus the flashing kit, collar and insulation. Assume the quote also includes the removal of all waste, including the old window.

However, quotes will not typically include any scaffold costs if required, though most windows can be fitted from inside, sometimes this is not possible, and a scaffold tower is the only safe option.
Typically, around 4-6 hours if everything goes smoothly, assuming a" like for like" replacement with no structural alterations to the roof required.
Not always, most common spare parts for Velux windows can be changed very easily, and they have an extensive spare parts catalogue for all their window types. Velux windows are high quality and designed to last for years, so when individual things wear out or break, you should be able to find and replace the most common spare parts yourself.
A roof window is categorised as an outward-facing window which is installed in a flat or pitched roof. It is commonly fitted as part of a loft conversion to improve natural light and ventilation.
If you have converted your loft into a bedroom, you may want to block out the light at night by fitting blinds. You can purchase normal blinds which can be operated via string or electrical blinds which can be controlled at the press of a button and are normally utilised in situations where loft windows are out of reach.

How to Find & Hire a Roof Window Replacer

To ensure your new roof window meets building regulations and is long-lasting, you should consider hiring a professional window fitter to install it for you. A typical labour rate for window specialists is around £100 to £200 per day.

When hiring a tradesman, it is important that you conduct a background check to ensure they are fully qualified for the job.

While window fitters do not require formal qualifications, however, you should make sure you only hire someone who is a member of a certification scheme such as CERTASS or the NRFC.

You can also visit Velux's website to find certified installers who have installed high-quality roof windows before and have at least five years' experience doing so.

You should also check that the window installer you hire has public liability and employer's liability insurance to protect everyone, including you in case anything goes wrong during the installation.