The short answer
The cost of a sun tunnel depends on the tube, the roof and the ceiling, not on one fixed figure. A rigid tube costs more than a flexible one, a longer run costs more than a short one, and slate or access by scaffold adds to the labour. We give one written price after seeing the roof and the loft, not a guess over the phone.
What decides the price of a sun tunnel, how rigid and flexible tubes differ, and which questions to put to anyone pricing one.
What a sun tunnel is and what you are paying for
A sun tunnel, also called a light tube or tubular rooflight, is a way to bring daylight into a room that has no wall or roof window. A clear dome on the roof collects light, a reflective tube carries it down through the loft, and a diffuser panel in the ceiling spreads it into the room. It suits a landing, a hallway, a walk-in wardrobe or a small bathroom where a full roof window would not fit.
The price covers four things: the kit, the roof opening, the run through the loft and the ceiling finish. The kit itself is the dome, a flashing for the roof, the tube and the diffuser. The roof opening needs the covering to be lifted and cut, and the flashing fitted so water cannot get in. The run through the loft depends on the distance and any obstacles. The ceiling needs a hole cut and made good.
Unlike a roof window, a sun tunnel gives no view and no ventilation, so it is a lighting product. Our answer on skylight light wells looks at the alternative for rooms where a window can go. Checkatrade's October 2026 table lists £1,250 as the UK average for fitting a new roof window, but that is a window figure, so do not read it across as a tube price.
Rigid or flexible tube
A rigid tube is made of straight sections with a mirror-like inner surface, and it carries light with the least loss. It is the better choice for a straight drop from roof to ceiling. The sections join with angled elbows when the route has to bend, but each elbow reduces the light a little, so the aim is to keep the run short and the bends few.
A flexible tube is a ribbed, stretchy duct, easier to route round rafters, pipes and wiring. It costs less and is quicker to fit in a cramped loft, but the ribs scatter light, so the room is dimmer for the same dome size. It can sag if not supported along its length, and the joints should be taped so that warm moist air from the room does not get into the loft around the tube.
Neither type is a bad choice on its own terms. Choose by the route: a short straight run suits rigid, a long winding route with obstacles may suit flexible, and a mix of the two is common. The tube should be insulated in the loft, since cold tubes in a cold space form condensation inside the room-side end, so ask what insulation is part of the price.
How the roof and the access change the price
The roof covering matters more than people expect. Cutting a clean hole in concrete tiles is one task, working into natural slate is another, and a flat roof needs a different kind of dome and a raised kerb. Our page on fitting a Velux in a slate roof explains why slate is handled with extra care, and a tube needs that same patience.
Access is the next factor. If the dome position can be reached from a ladder or a low roof, the job is quicker. If it sits on a steep slope or high above the ground, scaffold or a tower may be needed. Checkatrade's fascia and soffit table (September 2026) gives £300 to £600 a week for scaffold on one elevation, so access alone can rival the cost of the tube. Ask whether any quote includes scaffold and VAT.
Length is the third factor. The longer the run between roof and ceiling, the more tube, the more supports and the more labour. A tube in a loft that is hard to get around, with limited space between joists, takes longer to fit. Ceiling type matters too: lath and plaster takes more care than plasterboard.
Building control may want notice of a new opening in the roof, so ask your own building control body before work begins.
Getting a fair quote
Because the price depends on so many variables, a quote given without a survey is a guess. A reliable one comes after someone has looked at the roof, the loft and the ceiling. Photos of your roof surface and the loft route come back to you, which makes it clear what the number rests on.
Ours is a single total, written down, saying what is included and what the survey found, and it names the tube type we propose and why. Compare quotes by asking each tradesperson the same questions: rigid or flexible, how many bends, what insulation, what flashing, what is done to the ceiling, who clears the waste.
To start us off, send a picture of the room that needs the light, the roof above it and the ceiling height. Should the hatch be reachable, a shot of the void over the ceiling shows the route. Do not forget that a sun tunnel and a roof window can sit side by side in the same house, each in the room where it suits best.
Our roof windows and skylights hub shows the rest of the work, and the cost to fit a Velux window page gives national prices for the window side.
More on this in Velux Roof Windows & Skylights in Crawley
Two sun-tunnel questions
Is a shaded or north slope too dark for a light tube?
It still gathers daylight, since the dome catches light from the whole sky, not only direct sun. The room will be dimmer than with a south-facing dome, and early or late in the day the output falls. If you have a choice of slope, the sunnier one gives more light for the same tube.
Will a sun tunnel make the room cold?
A well-fitted tube loses little heat, but a poorly sealed or uninsulated one can create a cold spot and some condensation at the ceiling. Ask what insulation and seals are included. A sealed diffuser and an insulated tube through the loft keep the draught and the damp out.