What is the average cost of a VELUX window?

Two VELUX windows can be two different jobs. One is a small window swapped in a ready-made opening. The other is a larger window cut into a slope that had none, with the structure altered to take it. The brand is the same and the work is not.

An average blends those jobs into a figure that fits neither. It would also move with the mix of sizes and specifications sampled, and a window is only priced properly once its size, opening, glass and roof are known. Each one is taken in turn below.

VELUX sizes its roof windows by code, and the manufacturer publishes the width and height for each. Open the sash and a metal plate on its top edge comes into view. Anything VELUX produced after 1968 carries one, and the code stamped on it gives the width and height. The size codes guide walks through reading it.

A larger window brings more glass and a larger frame, and it asks more of the roof around it.

Opening style changes the specification. A fixed window has no moving parts to specify, a hand-operated one adds a sash that opens, and an electric one adds a motor, controls and a power supply. On the solar and electric models, a built-in sensor detects rainfall and shuts the sash by itself.

A bathroom may only need a hand-operated sash left ajar after a shower, while a landing may be happy with a fixed pane. The room under the glass drives the choice, so the survey takes in the room as well as the roof.

The VELUX glazing menu runs from a dirt-repellent coat that makes the outside easier to wipe, through a laminated inner pane meant to hold together if it is broken by accident, to a version tuned to quieten rain. Models differ in which of these they offer, so each choice is tied to the window being priced.

Every choice is a line in the specification. Choosing for a bedroom under a slate roof is a different exercise from choosing for a utility room.

The roof is half of the price conversation. A VELUX lies flush with the slope, and the flashing that seals it must suit the slates or tiles around it, so the covering is one of the first things noted. Pitch comes next, since the model is picked to match it. Then there is the timber behind the opening, which has to be sound enough to hold a new frame.

Access also plays a part. A slope you can reach from an open drive is a simpler proposition than one above a narrow passage, a conservatory or a steep drop, because the window and the materials have to be got up there somehow.

None of this can be read from a catalogue. It is why two quotes for the same model can differ, and why the survey comes before any figure is given.

Replacing a window in an existing opening, at the same size, is the simplest case. The like-for-like swap guide explains that case. A new opening is a bigger job: gov.wales notes that cutting one usually means altering the structure, and the roof then has to hold up the unit or be strengthened. A new or replacement roof window should also reach 1.4 W/m²K, or Window Energy Rating band B, under Approved Document L (Wales).

We handle the Building Regulations notification with local authority building control or a registered building control approver, where the work is notifiable. A new rooflight in the slope inside a conservation area, the Gower AONB, Bannau Brycheiniog National Park or a World Heritage Site also needs a planning application, covered in our answer on roof windows and planning in Wales.

When the survey has settled these points, you receive a fixed written quote, and the work carries a 10-year workmanship guarantee in writing. For the wider picture, see how much roof windows cost and the VELUX windows page. To book the survey, call 01792 929062 or fill in the form.