How Much Does It Cost to Install a Velux Window?

One national guide, MyJobQuote, sets out a standard mid-range Velux window at £1,100, and a straightforward swap at around £100 less (MyJobQuote, Sep 2026). That is a typical UK range figure for a common job, published by a cost website, and it is not a Taunton Prestige price. We do not publish prices of our own, because a roof window is priced from the roof it goes into.

What does fitting a Velux roof window cost?

On those figures, a mid-range fitted unit sits around £1,100, and a like-for-like swap into an existing opening sits a little under it. Both assume a common size, a standard flashing kit and access that does not need special arrangements. They give a sense of scale before anyone visits, and no more than that.

The words "mid-range" matter. The guide is describing a middle choice of size and specification, not the lowest-priced unit on the shelf and not an electric or solar one. If you want a bigger window, a motor or a blackout blind, expect the total to move.

The swap figure matters for a different reason. It shows that the opening is worth something: where a window already sits in a sound hole, the heavy structural work has been done once. Our page on replacing a window in the same opening explains what is saved and what is not.

Treat any figure you read online, including these, as a range of possible outcomes. A roof that needs scaffold, a slope with deep clay tiles and a window larger than a standard size can each lift the total beyond the guide.

How much is a Velux window?

The figure above is for a window fitted, so it includes work as well as glass and frame. The unit on its own is priced by its size, its glazing and the way it opens, and suppliers list their own prices. Because makers change their ranges and their discounts, a price copied from last year's catalogue is usually out of date.

What you can say is how the unit price is built. A bigger frame uses more timber and glass. A second pane or a coating added to reach the Part L figure costs more than the basic glazing. A centre-pivot, a top-hung and a conservation-style unit are different products, and a motorised one carries a motor and a control. Ask a supplier for the price of the exact specification, with the flashing kit for your covering listed beside it.

That kit is not an extra in the sense of being optional. A window without the right kit is unfinished, and the kit is made for one covering, as our guide to flashing kits by roof covering explains. A unit bought on its own and fitted by a roofer who then finds the kit wrong is a common source of a second bill.

When you compare supplier prices, compare like with like: same size, same opening type, same glazing, same kit. A low unit price that hides a missing kit or a thinner pane is no saving, and a higher one that includes the kit and the blind may work out less.

Remember also that the unit price excludes the work to fit it. That is where the roof itself starts to matter.

How much are Velux windows fitted?

The answer depends on the job, and these are the factors that move it.

• Size: a larger window is heavier to lift into place and needs a bigger flashing kit.
• Opening type and extras: electric operation, solar power, rain sensors and blinds add parts and wiring.
• The covering: slate, plain tile, interlocking tile and deep clay each need a different kit and a different method of dressing the courses.
• New opening or swap: a new hole needs the rafters cut and trimmed, and the room re-lined.
• Access: a low roof reached by ladder is quick, a high one may need scaffold or a tower.
• The lining inside: plasterboard, plaster, paint and a finished reveal.
• Surprises: soft timber, an old leak or a missing underlay found once the covering is lifted.

Some of these are choices you make, such as the size and the extras. Others are facts about the roof that only a survey finds. We look at the covering, the pitch, the timbers near the opening and the way in, photograph what we find, and set out a single total.

You can reduce the cost by choosing a standard size that matches an existing opening, a plain fit with a manual handle, and a time when other work is already on the roof. Fitting two windows in one visit can share the access and set-up between them.

What you should not cut is the quality of the flashing, the energy figure of the glazing or the care taken with the lining. Those are the parts that decide whether the window is dry and warm in ten years.

The biggest single difference in price is whether the roof already has a hole of the right size. A swap reuses the opening. A new window means a new opening, and that is structural work.

For a new opening, a roofer or builder cuts a rafter, the sloping timber that carries the slates or tiles, and fixes a trimmer each side to carry the load around the gap. The covering is cut back and made good. Inside, a lining is formed and finished. This takes more time, more timber and more tidying up, so the price is higher than for a swap by a clear margin.

Is Building Regulations approval needed for a new opening?

A new opening affects the structure, so check with your building control body before work starts. In Taunton's area that can be Somerset Building Control, 0300 303 7790. The window itself must reach the Part L figure for a new element: Table 4.2 of AD L Volume 1 (2021 edition, 2023 amendments) asks for 1.4 or Band B on the rating label, and note 8 brings roof windows into that row.

Planning is a separate question. Class C of the permitted development rules covers roof alterations to a house, with a limit of 0.15 metres on how far a unit can project from the slope. Listed houses need listed building consent in addition, and conservation areas and the Quantock, Blackdown and Mendip Hills National Landscapes are places to check with Somerset Council before work starts. Inside Exmoor National Park, ask Exmoor National Park Authority.

Our guide to fitting a new roof window follows a new opening step by step.

For a single window on a low roof, a ladder or tower may be enough. For a window on a higher slope, or where the roof is steep and the fitter needs a working platform, scaffold goes up, and it can account for a noticeable part of the bill.

MyJobQuote's guide to replacing roof tiles gives £550 to £750 for a front-elevation scaffold on a week-long hire (MyJobQuote, Oct 2026), and HomeBuilding's new-roof guide gives about £1,000 with permits for a three-bed semi (HomeBuilding, Sep 2025). Both are for whole-roof work and a longer hire than a window needs, so treat them as a sign of scale rather than a figure for your job. Shorter hire and shared use with other work change the picture.

Who applies for the scaffold?

Highways Act 1980 s169 governs any scaffold erected over a footway or carriageway, and the licence is the highway authority's to give. Somerset Council's licences are for accredited contractors, so whoever you appoint lodges the application. The fee is £124.60 per 28-day period (April 2026), with 10 working days' notice. Devon County Council expects the scaffolders to apply for their customers, at £158.

That notice period is worth knowing. A roof window job that needs scaffold on the highway cannot start the day after you say yes, and the date has to allow for the licence. Ask whoever quotes who applies and who pays, and whether that is in the total.

An internal job, such as a window over a stair that can be reached from inside the roof space, can sometimes avoid scaffold altogether. A roofer will say whether that is practical once the slope is seen.

A quote for window work should name the window clearly: size, opening type, glazing and make or range. It should say what flashing kit goes with it, whether scaffold is in the total and whether VAT is. Without those, two prices cannot be compared, and a gap between them tells you little. A higher figure may include the kit, the lining and the scaffold, while a lower one leaves them for later.

Once the survey is done the total arrives as one sum on paper, so what you read is the price for the job, not a range.

Can you cancel after agreeing?

On cancelling, the Consumer Contracts Regulations give 14 days for a contract made in your home following a survey, but not for a repair visit you request because it is urgent (regulation 28(1)(e)). If a dispute arises, the Citizens Advice consumer helpline on 0808 223 1133 can advise.

Keep the data sheet for the window you are given, since it records the Part L figure, and the paperwork for the flashing kit. They are useful if you sell the house or have to deal with a fault later, and a buyer's survey may ask where the window came from. File them with the other paperwork for the roof, together with the photos of the work taken before the covering was closed up.

If you have a window in mind, send us its size and a photo of the roof it will go in. We will tell you whether it is a swap or a new opening, ask what you want in the way of blinds or a motor, and then survey the roof and put the total in writing.