You’ve probably heard the words ‘Velux window’ and know that it means a skylight loft window. But, did you know that it’s only a brand name? Many companies make and fit branded roof windows which seem to be just as good as Velux. But, for this article, we’ll restrict ourselves to Velux Windows.
How much does a Velux window installation cost for a typical loft in the UK? Many people don’t realise that installing one of these isn’t just about cutting a hole in the roof and dropping a window into it. At each stage, the installer ensures the roof is weathertight and waterproof. And you pay for those skills. So, depending on the size of the window and its location you can expect to pay anything from £800 to £1,800.
Many householders, and you might be one of them, need windows when converting their loft into a living or bedroom. Alternatively, you might be considering a single storey kitchen extension and you’ll need natural light for that too. Velux windows do a great job in both of these situations and more. Moreover, you also need a means of escape in case of an emergency or fire. That’s where roof windows become extremely useful.
However, fitting a Velux window isn’t a job for the amateur. Even though they are expensive to install, you must have them fitted properly so that your weatherproofed roof isn’t compromised. There are plenty of Velux installers for you to choose from and if you choose wisely they will make a good job of it too.
Architects usually specify a window to be fitted at the same angle as the roof pitch so that it sits flush with the roof tiles. They give the loft space natural light, much–needed ventilation and provide an emergency exit if necessary. All in all, they are an important part of any loft or single–storey extension.
How Much Do Velux Windows Cost?
The cost of Velux window installation varies with size, style and location. The material costs featured below include the cost of the window, flashing kit, insulation, and waste disposal. Velux window prices and other material costs will stay constant across the country. However, the labour charges will be about 10% to 20% greater in London and Southeast.
Velux window sizes & prices:
|Window fitting task||Estimated time||Window size (mm)||Material cost||Labour charges||Total cost|
|Small Velux window installed in a bathroom||1 day||660mm x 980mm||£800 to £1,000||£300||£1,100 to £1,300|
|Large Velux window on a roof slope||1 day||1340mm x 1600mm||£1,200 to £1,600||£400||£1,600 to £2,000|
|Medium Velux window installed on a roof slope||1 day||940mm x 1180mm||£1,000 to £1,400||£400||£1,400 to £1,800|
|Replace small Velux window in an existing opening||4 to 6 hours||660mm x 980mm||£750 to £850||£150||£900 to £1,000|
Don’t forget other additional charges such as scaffolding for access to the roof. Your installer might not need these, as Velux windows are designed to be installed from indoors. But, you should allow for this cost. Depending on the accessibility of the roof area, you might have to hire scaffold from a specialist company. Or, the window fitter might own a scaffold tower.
Velux Replacement Codes
After 1968 Velux Windows introduced a serial number system for each of its windows. If you need a replacement for an existing Velux or need spare parts, you only have to look on the existing window and find the code number.
You can find the serial number plate (shown below) in the top right–hand corner of the frame. You have to open the sash first as the plate is invisible when the window is closed.
The plate gives information to the manufacturer that gives the exact specifications of the window.
- This number specifies the ‘Type’. If you’re shopping for another window you can alter the ‘Type’ but you can’t alter the ‘Size’ unless you change the opening size.
- Here you’ll find information on ‘Size’. You can only change this if you enlarge or reduce the size of the opening where the window frame fits.
- This is the ‘Variant’ code number. This number refers to items such as glazing, window finish and type of opening. Therefore you can change this specification as long as the size remains constant.
- The ‘Production Code’. This code provides additional information for the manufacturer.
Installation types: Standard and Recessed
The manufacturer offers Velux windows in two installation types.
- The standard installation allows the external window surfaces to be flush with the roof tiles.
- Recessed installation, sets the window 40mm below the roof tiles.
Although you can choose either option, Velux recommends the ‘Recessed’ version as this will make it easier for the window to achieve its stated energy performance. It also offers more design options for your architect.
Velux Window Benefits & Features
You’ve probably guessed by now that Velux windows are a modular product with various interchangeable items. This gives the purchaser added freedom to choose exactly the style they want and any extra features.
Not only do they offer the standard variations you would expect such as:
- Centre or top hung window sashes.
- Electric, solar–powered or manual opening controls.
- Roof terrace, balcony or standard roof windows.
They also offer special function windows for added choice.
- Super Sound Insulation reduces external noise from motorways or airports by up to 50% when compared to a standard Velux window.
- Burglary Resistant roof windows have added security features if the window is easily accessible from the roof. This option offers toughened and laminated glass, reinforced construction and additional locks.
- Smoke sensors activate the opening mechanism on the Smoke Ventilation windows and have a manual override ‘break glass point’ if needed. Obviously, these windows also have normal day-to-day natural ventilation controls too.
- If you need Passive House certified building components for your project, then Velux offer their Passive House Roof Windows. These are triple glazed for maximum heat efficiency and are powered by solar energy for opening the window, shutters and blinds.
Velux Fittings & Finishings
When you buy a Velux window, that’s not all you receive. You get everything you need to install the window and make it watertight. All you supply are the tools and labour! The typical kit includes:
- Velux flashings. This ensures your window remains waterproof. It provides the perfect interface between the window and your roof.
- Underfelt Collar. This pleated underfelt gives a tight seal between the window and your roofing felt.
- Water drainage gutter. The gutter diverts rainwater from above the window so it runs down either side of the window.
- Insulation frame. This frame provides a tight foam insulated fit between the window and the roof timbers.
- Vapour barrier collar. This collar keeps everything vapour and airtight.
- Interior lining. These are prefabricated linings to make sure everything is airtight on the interior.
- Lining frame kit. This is an adjustable steel frame to fit onto the on-site timber lining. It also includes a vapour barrier collar.
A window couldn’t do its job without glass. Velux provides many different options for you to choose from. The variations provide heat insulation, added strength and security, protection from the weather and give extra sound insulation.
- Safety glass comes as standard and consists of a toughened exterior glass pane, an inner laminated pane and a heat loss efficiency U-value of 1.3 W/m2K.
- Standard Plus is a triple glazed version for increased thermal and acoustic insulation. This also has a laminated inner pane. Its U-value is 1.1 W/m2K.
- Extra Low Energy is easy to clean and has glass panes coated with a layer to shed rainwater. It’s also triple glazed and is an excellent thermal insulator with a U-value of 1.0 W/m2K.
- Extra Noise Reduction focusses more on noise reduction and is great if you live near a noisy motorway or airport. It’s a triple glazed unit with an external coating to prevent condensation as well as a U-value of 0.81 W/m2K. It’s therefore good at heat retention too.
How to Fit a Velux Window
Although Velux windows come with easy-to-read installation instructions, they aren’t suitable for the amateur to install. Fitting a roof window of any type requires cutting into the structure of your roof and needs expert carpentry skills as well as a knowledge of the UK Building Regulations and Planning Permission constraints, if applicable. Fortunately, Velux windows are all fully compliant with the Building Control regulations so as long as the professional follows the instructions and has knowledge of roof construction, everything should be okay.
Consult the local authority
First, decide whereabouts in the roof you want the Velux window and find out from the local authority if there are any constraints.
Make sure you know the Building Regulations and follow them because the Building Control Officer will inspect the work at various stages. Ensure you don’t weaken the roof structure when cutting an opening for the window.
Make a hole
Remove enough tiles to provide room to install the frame. Follow the same procedure if you have a slate roof. However, you might find there’s more chance of breaking slates compared to tiles. Removal involves lifting tiles, cutting battens and cutting into the roofing felt. You can do this from inside the roof space if you want to, in fact, it’s probably simpler to do so. Once you’ve removed the tiles and felt, you can cut into the rafters to provide the correct sized opening. Probably, you’ll have to insert strengthening timbers and supports to prevent the roof from collapsing as well as providing a support frame for the Velux.
Remove the sash from the Velux and fit the frame into the opening using the fixing brackets. Next, install the flashing to keep the joint watertight, and replace the tiles up to the frame. You will probably have to cut a few to make them fit.
Refit the sash into the frame and it’s watertight. So, you can now concentrate on the inside.
Remember that these instructions are generic and might differ from those provided by Velux. At all times follow the manufacturer’s instructions in preference to these.
Velux Window Cost Q&A
Q. Do you need planning permission for a Velux window?
Usually, as long as you aren’t changing the height or profile of the roofline, there’s no need to apply for Planning Permission. However, if you live in a listed building or a conservation area, you might have to follow certain constraints. Do note, because you are cutting into the roof and probably altering its strength and structural timbers, you will have to comply with the Building Regulations. These cover all structural aspects of the roof as well as ventilation, energy conservation, access and fire exits.
Q. How long should a Velux window last?
If the Velux window has been installed correctly, they are guaranteed by Velux for 10 years. But, they only guarantee additional electrical accessories, blinds and shutters for 3 years. However, many Velux windows were installed when they first started producing, more than 30 years ago. And, these are still in good working order. The owners merely preferred to have an updated model. So, it looks like their working life could be many more years than the guarantee.
Q. How do you care for a Velux window?
It’s very simple to care for a Velux window. According to the manufacturer’s instructions, you should only use water with a soft and clean, lint-free cloth or a non-abrasive sponge to remove any dirt from the frame. You can also clean the glass using a clean, non-metal window squeegee.
You can buy a Velux maintenance kit direct from the manufacturer. This includes lubricating gel for hinges, scratch touch-up kit, new air filter, and touch-up paint. At the time of writing these cost just under £30.
Q. What are the alternatives to Velux?
There are many alternatives to Velux windows. These tend to be cheaper than Velux because they’re less well known. However, Velux produces a good product and their customer support is superb. Furthermore, it isn’t unknown for the company to send fitters as a gesture of goodwill to repair windows free of charge whose guarantees have expired.
Alternative companies that produce modular skylight windows include:
- Keystone Group
- Keylite Roof Windows
Get Velux Installation Quotes
Installing a skylight in your loft or a new single-storey extension will provide much-needed daylight to brighten up dim and dark corners. You may want to compare quotes before going ahead with the project. By filling out the form on the top of this page, you can find out the average cost of Velux window installation. The service is free of charge & there is no obligation to go ahead unless you’re satisfied with the price.