How Much Does a Velux Window Cost in 2026?

Velux Window Fitting Costs

These are the prices UK firms publish for supplying and fitting a roof window, and almost all include the window and flashing kit. The main figure is the middle price, and the range covers the middle half of firms, except where we say it's a guide or an estimate.

Replacement cost by size

Worked out from the four firms that price replacements by size.

VELUX's own replacement service says its average is £1,200 to £1,600 a window. A new window depends more on the roof: a trussed roof, slates, or a window wider than the gap between rafters all take longer. If you buy the window yourself, labour only is roughly £600 for a swap and £900 for a new opening. Our Velux window sizes guide explains every size code if you're not sure of yours.

Velux Window Cost Calculator

Choose the job, size and type for a rough price before you ask for quotes.

Velux Window Prices by Size

Prices for the window only: a VELUX GGL white painted centre-pivot, the standard type, from online merchants, including VAT. The range is the middle half of merchants, and an MK04 cost from about £350 to £450 depending on where you bought it. The flashing kit is extra, at about £120 for an MK04 on tiles or slates.

78 x 98 cm (MK04) windows by type

VELUX's list price for a white painted MK04 is £503 including VAT, so online merchants sell about 25% below it. Pine costs the same as white painted or more at every merchant we checked, so it won't save you anything. A top-hung window opens wider, and in a big enough size it's the type used where a window has to work as a fire escape (see escape window sizes).

Velux, Keylite and FAKRO Compared

Velux is a brand name: the windows are made by the VELUX Group, a Danish company, and the name is so well known that people call almost any roof window a Velux. The other big makes on merchants' shelves are Keylite and FAKRO, and all three come in the same common sizes, give or take a few millimetres. Here's what a 78 x 98 cm window with its flashing kit costs at merchants.

Switching between the three saves little, but budget ranges cost about £100 to £150 less than a standard VELUX: VELUX's own basic range starts at about £280 and Optilight at about £250. Dakea, another budget make, belongs to the VELUX Group. VELUX, Keylite and FAKRO are trade marks of their owners, and Less.co.uk isn't connected with any of these makers.

Extras and Other Costs

Replacing an older window can also need an adaptor so the new flashing fits, which VELUX lists at £110 for an MK04. Firms rarely publish prices for an engineer, so treat that figure as rough.

Planning Permission and Building Regulations

Planning permission (England)

Most houses can add roof windows without planning permission, under permitted development rights. The window can't stick out more than 150 mm from the roof slope or sit higher than the highest part of the roof. On a side-facing slope it has to be obscure-glazed, and it can only open if the opening part is more than 1.7 m above the floor. Flats and maisonettes don't have these rights, listed buildings need listed building consent, and some councils remove the rights in conservation areas, so check with yours. A householder planning application in England costs £548.

Building regulations

A new roof window alters the roof structure, so the Planning Portal says building regulations approval will generally be needed. No competent person scheme covers new openings, so it goes to council or private building control, usually for about £375.

Replacing a whole roof window, frame and all, is building work too. You can read that a same-size swap needs no approval, but that only holds when the fitter is registered with a competent person scheme such as FENSA or CERTASS and certifies the work for you. Otherwise you tell building control before the work starts, which costs about £300. Replacing just the glass in the existing frame isn't covered.

When to Replace or Repair a Velux Window

VELUX says roof windows last 20 to 30 years, or longer if they're looked after. The signs one is near the end are water dripping in after rain, condensation that never clears, and glass that's cracked, cloudy or yellowed.

If the frame is sound, a repair can be much cheaper. A new sealed glazing unit costs £200 to £450 fitted, although some VELUX panes aren't sold on their own, and fixing a leak at the flashing costs £150 to £600. For damage to the roof around the window, see our roof repair costs.

VELUX guarantees its roof windows for 10 years against manufacturing faults, including the glazing and flashing, with 5 years on electric parts (10 if you register them), 3 years on manual blinds and 5 on electric or solar blinds. Its 10-year installation guarantee only comes through its own fitting service or a VELUX certified installer. With any other fitter, the workmanship guarantee is whatever the firm offers, so ask for it in writing.

Flat Roof Skylight Costs

A flat roof takes a rooflight that sits on a raised kerb, not a pitched roof window. A fixed 1 m x 1 m rooflight costs about £940 from merchants, with domes from about £600, and an opening one, usually electric, about £1,570.

Fitted into an existing flat roof, expect about £2,000 for a fixed rooflight (£1,500 to £2,500) and about £2,750 for an opening one (£2,200 to £3,500). Few firms publish these prices, so treat them as a guide. If the flat roof is near the end of its life, it's cheaper to add the rooflight when it's re-covered (see flat roof costs).

Can You Fit a Velux Window Yourself?

VELUX strongly advises using one of its certified installers. Its product guarantee covers manufacturing faults only, so it won't pay out for problems caused by the fitting. A new opening means cutting the roof structure, getting the flashing watertight and having building control check it, which is beyond most DIYers.

A like-for-like swap is more manageable for a confident DIYer with a head for heights, but in England and Wales you'd have to apply to building control yourself, at about £225 to £375. Blinds are the easy part: they clip into the frame in minutes.

Velux Window Fitting Prices by Region

A new roof window fitted in each region. The window and flashing kit cost the same everywhere online, so only the fitting part of the price is adjusted for local building costs. The firms we found didn't show a clear regional pattern, apart from London and the South East tending to cost more.

Regional prices use the BCIS location factors published by the Department for Education (December 2025), with the Valuation Office Agency's figure for Wales. There's no current official figure for Scotland, so we show the UK price there. How we work out regional prices.

How to Get Your Velux Window for Less

How a New Roof Window Is Fitted

A new window usually takes 1 to 2 days, plus drying time before the inside is decorated. A straight replacement skips most of these steps and takes about 4 hours.

1. 1

   Survey and quote

   The fitter checks the roof from inside and out: where the rafters or trusses are, the roof covering and pitch, and the size and position you want. A trussed roof or a window wider than the rafter spacing may need an engineer's design. They should apply for building control approval before starting.

2. 2

   The opening is cut

   Tiles or slates come off, the felt is cut, and any rafter in the way is cut and trimmed, with doubled timbers either side to carry the load.

3. 3

   Window and flashing go in

   The frame is fixed into the opening with its insulation and underfelt collars, the flashing kit is fitted around it, and the tiles or slates go back over the flashing.

4. 4

   The inside is lined

   The reveal around the window is boarded, plastered and left to dry before decorating. Check whether this is in the quote, as some firms charge for it separately.

5. 5

   Building control signs it off

   An inspector checks the work, and you get a completion certificate. Keep it with the house deeds, as you'll need it when you sell.

Frequently Asked Questions