How much does a sun tunnel cost?
Considerably less than a rooflight, and the run length is what moves it.
Part of our Sun Tunnel Installation guide
Substantially less than a rooflight, because there is no structural opening, no trimming and no large glazed unit.
What moves it
Diameter. 250mm is the standard domestic size; 350mm costs more and delivers roughly double the light.
Run length. More tube, and more importantly more labour getting it through the roof space cleanly.
Bends. Each elbow adds a component and adds time. A straight drop is quickest and performs best.
Rigid or flexible. Rigid costs a little more and performs far better. We specify rigid unless there is genuinely no straight route.
The covering. The collector is flashed in like a small rooflight, so a profiled tile needs the right flashing and a slate roof is straightforward.
Access. A bungalow or single storey roof is simple. A two storey roof may need scaffold, which on a job of this size is a significant proportion of the total.
A light kit, if you want the fitting to work after dark. Much cheaper fitted at the same time.
Two at once
Where a hallway and a bathroom both need one, doing them in a single visit shares the access and the roof work, and it is meaningfully cheaper than two separate jobs.
Against a rooflight
Where a rooflight is possible it gives far more light. A sun tunnel is not the budget version of a rooflight; it is the answer where a rooflight cannot go.
The cheapest daylight in this trade
A sun tunnel costs a fraction of a rooflight, and the range is narrower than most work we do because there is less to go wrong and less to vary.
Five things move it.
Rigid or flexible. The biggest factor and, honestly, not much of a choice. A rigid mirrored tube costs more and delivers roughly three times the light of a flexible foil one over a typical run. We fit rigid wherever the route allows it.
The run length. A short drop from roof to ceiling in a bungalow or a first floor room is a morning. A long run down through a loft and a first floor void to a ground floor ceiling needs more tube, more joints and more time, and it loses light on the way.
Whether the route is clear. Purlins, water tanks, soil pipes, steels and cables all live in loft space. Where the ideal ceiling position and the ideal roof position do not line up, the tube takes a bend, which is more work and less light.
Diameter. 250mm, 350mm and 530mm are the common sizes and each step up costs more. Output goes with area rather than width, so the step from 250 to 350 roughly doubles the light.
The covering. Slate and plain tile are straightforward. Profiled tiles need the matching flashing profile. Handmade clay is slow and a proportion breaks.
Why access barely features
Unlike a rooflight, the roof component is small and most of the work is from inside. On a bungalow it is reachable from a tower on almost any plot, which removes the line that most often surprises people on a quotation.
That is a large part of why sun tunnels are such good value on single storey property.
Two rather than one
Two smaller tunnels frequently beat one large one, because two pools of light read as ambient daylight while one reads as a spotlight in the middle of the ceiling.
Where two are being fitted in the same visit, the second costs meaningfully less than the first because the access, the protection and the setting up are shared.
What should be included
The kit with diameter and whether the tube is rigid or flexible. The flashing, and which profile for your covering. Insulation to the tube where it crosses unheated loft space, which is not an optional extra. An airtight seal at the ceiling ring. Making good to the ceiling, and whether decoration is included. Disposal.
The insulation and the airtight seal are the two lines that get left off cheap quotations, and their absence produces condensation running down the tube to the diffuser, which then gets reported as a leak.
Optional extras worth having
A light fitting inside the diffuser, so the same ceiling opening works after dark. A glass dome rather than polycarbonate on a south facing roof, because polycarbonate yellows under ultraviolet over fifteen to twenty years while glass does not.
Why it is the best value daylight we fit
Two reasons, and both come from the scale of the work. The roof component is small, so the access that dominates a rooflight quotation barely features. And most of the work is from inside, so on a bungalow it is frequently a half day job with no scaffold at all.
For a windowless bathroom or hallway, nothing else comes close on cost, and it is why we recommend it over a rooflight on a fair number of jobs.
Ask us
Send a photograph of the roof and one of the loft space, and tell us which room you want lit. That is enough for a realistic range by email, free and without an appointment.
The two lines that get left off
Insulation to the tube where it crosses unheated loft space, and an airtight seal at the ceiling ring. Neither is an optional extra. Without them, warm room air gets into the tube, condenses on the cold metal, and the water arrives at the diffuser looking exactly like a leak.
One last point
Where two tunnels are fitted in the same visit, the second costs meaningfully less than the first, because the access, protection and setting up are shared. Two smaller tunnels usually beat one larger one.
More on Sun Tunnel Installation
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