Do sun tunnels work at dusk?

Only as long as there is daylight to collect. As the light drops, the output fades with it, and a light kit takes over for the evening.

Do sun tunnels work in winter?

In brief

Yes. A sun tunnel works all year, because it carries whatever daylight reaches the roof. In winter the days are shorter and the sun is lower, and cloud is common, so the room is lit less strongly than in summer, and at night the tunnel gives no light unless a light kit has been fitted. A room that was dark before will still be noticeably lighter in daytime.

A sun tunnel is passive: it passes on daylight and makes none of its own
Winter output is lower because days are short, the sun is low and cloud is frequent
A dull day still gives a soft, even light compared with an unlit room
At night there is no daylight to collect, so a light kit is needed for evening use
Clean domes, tight tubes and a good roof position help most in the darker months

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What changes between summer and winter

Nothing about the tunnel itself changes. The dome, the tube and the diffuser do the same job in January as in July. What changes is the daylight available to collect. In midwinter the sun stays low in the sky and sets early, the hours between sunrise and sunset are fewer, and a thick grey sky is more likely than a clear one.

The result is a sun tunnel that gives a quieter, flatter light in winter and a livelier one in summer. In a hallway or bathroom that means the room feels lit in the middle of the day rather than brightly sunlit. For most uses that is exactly what is wanted, since you are replacing a bulb that would otherwise be on all day.

Overcast days

Cloud scatters daylight rather than blocking all of it, and a dome collects scattered light from the whole sky. A sun tunnel therefore keeps working on a grey morning, with less strength and with no hard shafts of sun. Rooms on the landing or a hallway that rely on the tunnel will look gentle rather than dim.

How much that is in practice depends on the tube size, the type of tube, the length and the position of the dome. Those are the same factors covered in how much light a sun tunnel gives, and the maker's published guidance for each model is the best guide. We do not promise a particular brightness for any room.

Rooms that borrow light from a landing window or a glazed door will see a smaller change than a room with no other daylight. The more enclosed the space, the more the tunnel is noticed. A windowless bathroom or a cloakroom often shows the biggest difference between lights on and lights off at midday.

Evenings and a light kit

In winter the working day often ends in the dark, and a windowless hallway with a plain tunnel needs its ordinary ceiling light as soon as the daylight fades. For that reason some owners choose a sun tunnel with a light kit. This is a small lamp fitted inside the diffuser and wired to a switch, so the same ceiling opening gives light by day from the roof and by night from the lamp.

The lamp is wired on a normal lighting circuit, so the cable goes in during the electrician's first fix, ahead of the plasterer
A light kit is quoted as an extra and named in the written quote
The kit fits inside the tube or the diffuser, so the daytime appearance of the room does not change

If you are not sure whether an evening light is wanted, mention it when we visit and we can price the tunnel both ways.

Keeping a tunnel working through the dark months

A few details help the tunnel do its best when daylight is scarce. The dome should be clear, so a wash with water and a soft cloth now and then keeps leaves, moss and bird droppings from dimming it. The tube should be straight and tight, because a slack flexible tube loses light. Where there is a choice, a rigid tube loses less over a long run; rigid or flexible sun tunnel compares the two.

Position helps as well. A dome on a south-facing slope, clear of trees and a taller neighbouring roof, collects the low winter sun for longer. We look at shading and aspect when we survey the roof, so the dome goes where it will do the most.

Warmth, condensation and the tube

A sun tunnel passes through the loft, and the tube is sealed at the dome and at the diffuser so that warm air from the room below does not carry moisture up into the cold space. Good fitting matters here more in winter than in summer: joints are taped, the tube is kept clear of insulation gaps, and the ceiling fitting is sealed to the plasterboard. Where the tube crosses a cold loft, some makers supply an insulating sleeve. We follow the maker's instructions for the model chosen.

The fitting meets the Building Regulations in force, and our work has a 10-year workmanship guarantee behind it.

Is it worth it for a dark winter room

A sun tunnel is best judged against the room as it is now. A landing with no window that needs a light on at nine in the morning will see that change on most winter days, even if the light is subdued. A bathroom that stays gloomy until noon will do the same. If the aim is a view of the sky, plenty of light for reading, or ventilation, a roof window may be the better answer, and sun tunnel or skylight sets out the differences.

For help choosing, ask for a survey. We look at the roof, the loft run and the room, and send a written quote naming the model, the tube type, any light kit and the lead time stated by the maker. The overall range is on our sun tunnels page, and what a sun tunnel costs explains what the quote contains.