How Much Does a Sun Tunnel Cost in 2026? (UK)
A sun tunnel costs between £500 and £1,800 fully fitted in 2026. Rigid-tube 250mm units sit at the bottom of the range (£500–£900 fitted), flexible 350mm units come in at £700–£1,200, and electric-powered models with integrated LED for hallways and stairwells run £1,200–£1,800. That is a fraction of a roof light — typically £2,500–£5,000 fitted — and a far cheaper way to bring natural daylight into a windowless bathroom, en-suite, landing or walk-in wardrobe. Here is the full cost breakdown, the four factors that move the price, and the cases where a roof light is the better spend.
Planning the work? Check what it usually costs, or work out your own estimate. The free quote form is at the top of this page.
2026 sun tunnel cost breakdown
| Type | Diameter | Fitted price | Light output |
|---|---|---|---|
| Rigid sun tunnel | 250mm (10") | £500–£900 | Equivalent to a 60W bulb |
| Rigid sun tunnel | 350mm (14") | £700–£1,100 | Equivalent to a 100W bulb |
| Flexible sun tunnel | 250mm (10") | £550–£950 | ~70% of rigid (bends lose light) |
| Flexible sun tunnel | 350mm (14") | £750–£1,200 | ~70% of rigid |
| Electric (with LED) | 350mm (14") | £1,200–£1,800 | Daylight + nighttime LED |
| Comparison: standard roof light | 550 x 980mm | £2,500–£5,000 | Daylight + opening, view |
What's included in a fitted price
- The dome, reflective tube (rigid or flexible), ceiling diffuser and flashing kit
- Roofer's labour (typically 4–6 hours one-man job)
- Internal plasterboard cutout and skim of the ceiling diffuser ring
- Make-good of the loft insulation around the tube
- 10-year workmanship guarantee from a FENSA/CERTASS-registered installer
Four factors that move the price
1. Run length and number of bends
A straight 1.0m run (typical) is at the bottom of the range. Every metre of tube adds roughly £50; every 30° bend in a flexible-tube install costs about £40 and reduces light output by 5–10%.
2. Roof finish
Standard tile or slate is the baseline. Lead-flashed Welsh slate, single-ply membrane, or fibre-cement slate (Marley Eternit, Cembrit) typically add £100–£250 in flashing-kit cost.
3. Internal ceiling height and run-through
A first-floor bedroom with the unit directly under the loft is the easy case. A ground-floor hallway under a bedroom (i.e. the tube has to box through the bedroom floor void) is a different job altogether — typically £300–£600 extra for boxing and decoration.
4. Brand and dome quality
Velux SUN sells at a 25–35% premium over Lightway or Solatube equivalents. The premium buys you flood-rated flashing kits, a 10-year manufacturer warranty, and parts availability for the next 20 years.
When is a roof light better value than a sun tunnel?
A roof light wins when (a) the room needs ventilation as well as light, (b) you want a view out, or (c) you are planning a loft conversion within five years anyway (in which case a flush-fit Velux is on your future drawings and a sun tunnel becomes a sunk cost). A sun tunnel wins for windowless bathrooms, en-suites, downstairs WCs, internal corridors and walk-in wardrobes where ventilation isn't the bottleneck and openings are not desirable.
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