How a tubular skylight works
A clear dome on the roof catches sunlight, including low morning and afternoon light. The tube below is lined with a highly reflective surface, so the light bounces down through the roof space with little loss. At the ceiling, a diffuser spreads it into a soft, even glow that looks a lot like a light fitting switched on.
Because the ceiling opening is small, there's no shaft to frame or plaster. Most installs are a hole in the roof, a hole in the ceiling and the tube between them.
What decides how bright it is
Tube width. A wider tube carries more light. Solatube, a maker, says its 250 mm model lights about 19 m2 and its 350 mm model about 28 m2, with the dome in direct sun. A hallway needs far less than a living room.
Length and bends. Every elbow and extra stretch of tube loses some light, and each model has a maximum run. A short, straight run from a sunny slope gives the brightest result, so a good installer picks the roof position for the tube, not just the ceiling spot.
Sun and pitch. Your Home says tubular skylights work best in sunny, clear climates. Check the model suits your roof pitch too: Velux lists its flexible and rigid sun tunnels for pitches from 15 to 60 degrees.
The other kind: solar-powered opening skylights
These are standard glazed skylights with a motor run by a small built-in solar panel and battery, opened by remote or wall switch. Because no wiring is run to them, they're popular over kitchens and bathrooms where you want to let steam and heat out.
They cost far more than a tubular unit and need a full light shaft, so they're priced and installed like the fixed skylights on our main skylights page.
What you can do, and what a roofer should do
You can
- Pick the ceiling spot where you most want light, and say which rooms are darkest
- Look at which roof slopes get sun and which sit in shade
- Ask about add-ons like a dimmer, night light or exhaust fan before install day
Leave to a roofer
- Cutting the roof and fitting the dome flashing for your roof type
- Running the tube with as few bends as possible
- Sealing the ceiling diffuser and checking insulation around the tube
- Wiring for any motor or light add-on, by a licensed electrician
Our take
For a windowless bathroom, hallway or robe, a tubular skylight is one of the cheapest ways to change how a room feels, and we'd do it. Ask each installer where they'd put the dome and how many bends the tube needs. The one who plans the shortest, straightest run usually delivers the brightest room. If you want to open it for ventilation, that's a solar-powered opening skylight, and a different budget.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.