Some rooms are dark because of where they sit in the house, not because anyone planned it. A landing with a door at each end. A bathroom between two bedrooms. A hallway that runs back from the front door into the middle of the plan. None has a wall that faces the outside, so none can have a window in the ordinary sense.
A sun tunnel is made for exactly those rooms. A small skylight on the roof gathers daylight, a mirror-lined tube carries it through the space above the ceiling, and a diffuser spreads it into the room below. This guide looks at where to put a sun tunnel, which sun tunnel uses make the most sense, and where another kind of glazing is the better choice.
If you are new to the idea, the sun tunnel hub explains the parts and how they fit together. What follows is about placement, room by room and roof by roof.
The test: does the room have a roof above it?
Every sun tunnel needs a straight-ish path from the sky to the ceiling. So the first question is not which room is darkest. It is which dark room has a roof, or a short roof space, above it.
A room on the top floor, under a pitched roof, passes the test easily. The loft space above its ceiling is where the tube runs. A room on the ground floor of a two-storey house has a bedroom or a bathroom above it, and the tube would have to pass through that floor, which is rarely sensible. A flat or lean-to roof over a single-storey extension is different again: the roof is right there.
Walk through your house and mark the dark rooms. Then ask of each one, what is directly over my head? If the answer is a loft, a sloping roof or a flat roof, a sun tunnel is a candidate. If the answer is another room, look at the other options later in this guide.
Landings and stairwells
The upstairs landing is the textbook case. Closed in by bedroom doors, it occupies the middle of the plan while the stairwell drops away below. In the daytime it can be gloomy enough to need the light on, and the stairs below it can be worse.
A sun tunnel over the landing puts a pool of daylight at the head of the stairs, and some of it spills down the stairwell. It also suits the sort of room where you pass through rather than stay. A landing needs light, but it does not need a view, and a diffuser in the ceiling is a clean, small answer.
A landing under a loft usually has a short, direct route, since the loft sits right above it. That keeps the tube short and the light strong. If the loft has been converted into a bedroom, the route changes and the surveyor will need to look at what sits above the landing now. Either way the question is a practical one, and the survey answers it.
Bathrooms, shower rooms and cloakrooms
Bathrooms are often tucked into the middle of the house, away from the outside walls, so they are natural homes for a sun tunnel. Daylight in a bathroom makes it feel cleaner, and a morning wash in natural light is a different experience from one under a downlight.
Moisture matters here. A bathroom produces steam, and steam reaches the diffuser and the tube. The tube is sealed against it, and the diffuser keeps the room side closed. If a bathroom also needs better air movement, ask about a ventilating version, which carries air out as well as light in. It is a different product from the plain unit, so mention it at the start.
Privacy is the other point. A diffuser is frosted or patterned, so nobody can see in, and it faces straight up, so neighbours cannot see in either. That is one reason a sun tunnel suits a bathroom better than a window that looks out at a fence.
| Room | Why it suits | Watch for | Option |
|---|---|---|---|
| Landing | No outside wall | A converted loft above | Sun tunnel |
| Bathroom | Private, steamy | Air movement | Ventilating unit |
| Hallway | Long and enclosed | Run length | Tube choice |
| Walk-in wardrobe | Small, windowless | Tube width | Small diffuser |
| Utility room | Often internal | Roof position | Sun tunnel |
Hallways and entrance halls
From the front door a hallway tends to run toward the heart of the house, and its far end can be dim even at midday. A sun tunnel at that far end lights the part the front door glass cannot reach.
Think about the pattern of use. A hallway is passed through many times a day, and daylight changes the feel of it for everyone who does. A pair of small diffusers can work better than one large one in a long hall, because they spread the light along the length. Whether that suits your house depends on the roof above, and the surveyor will say.
Where a pitched roof and a loft sit over the hallway, the job is simple. A hallway in a bungalow is simpler still, since the roof space sits straight over the ceiling. A hallway in a modern house with a tight roof space may need a flexible section to get round trusses. The shape of the roof structure above is the deciding factor.
Walk-in wardrobes, dressing rooms and utility rooms
Small rooms with no windows gain the most from a sun tunnel in proportion to their size. A walk-in wardrobe is a good example. Seeing the true colour of clothes is easier in daylight, and a modest tube lights a small space well.
A utility room that sits in the middle of the plan, or a boot room carved out of a larger space, is the same story. The room does a practical job, and a pool of daylight makes the job easier. A corridor study or a small home office with no window is a candidate too.
The principle is the same for all of them. A sun tunnel is a good match for a room that is small, has no outside wall and sits under a roof. It is a poor match for a big room that needs light across its whole floor, which is the job of a larger rooflight.
Kitchens, living spaces and extensions
A kitchen with a window at one end can still have a dark far corner. A sun tunnel is an option there, but it is a small light source, and it works as an accent rather than as the main source of daylight.
A kitchen extension that has a flat roof is usually better served by a flat-roof glazing unit or a lantern. They are made for large floor areas and they bring in a broad wash of light, where a sun tunnel brings a pool. A roof lantern can sit over the dining table or the island and light the whole zone.
There is no rule that a room must have one or the other. A sun tunnel can light a corridor off the kitchen, or a pantry, while a larger rooflight lights the kitchen itself. The surveyor can suggest the mix that fits the house.
Pitched roofs, flat roofs and awkward roofs
Sun tunnels fit on many roofs, but the roof decides how the dome is fixed. On a pitched roof the dome sits on a flashing that suits the tile or slate, and the tube drops through the loft. On a flat roof the dome sits on an upstand, and the tube drops through the ceiling void. On a low-pitched roof, the dome and flashing are a little different again.
Orientation matters less than people expect. A dome catches light from all across the sky, so a north-facing slope still works. A roof in the shade of a tree is a different matter, and a dome under heavy branches will carry less. Look at what stands between your roof and the open sky.
Roof structure is the real constraint. A modern roof built with trusses leaves less room for a wide tube than an older cut roof. A loft full of ducts, a water tank or heavily boarded storage space needs working round. None of these stops a sun tunnel, but each shapes the route.
Where a sun tunnel is the wrong answer
Honest advice includes the cases where a tube is not the answer. A room that needs a view needs a window. A large room that needs even light across a wide floor needs a bigger rooflight. A room that sits under a long run of other rooms, with no short path to the roof, may not suit a tube at all.
A loft conversion wants a roof window, which opens, gives a view and, in a bungalow loft within 4.5 m of the ground, can serve as an escape window. A sun tunnel does none of that. If you are converting a loft, read roof windows before choosing. And if you are unsure whether a tube or a window is the right tool, is a sun tunnel the same as a roof window lines up the two side by side.
A sun tunnel also does not replace every light in the room. It brings daylight in the day. For evenings, a light kit can be added to the tube, or ordinary room lighting does the job.
Before you choose a spot
- Does the room have a roof or roof space above it?
- Is it a small room with no outside wall?
- Is a view needed, or only light?
- What sits between the roof and the ceiling?
- Would a larger rooflight suit the room better?
Replacing an old sun tunnel in the same place
If a sun tunnel is already in the ceiling and has gone dull, the position is already proven. Replacing it means the route is known, the opening exists and the room is used to the light.
But it is worth a fresh look at the position. Rooms change. A landing that once sat under an open loft may now sit under a converted bedroom. A tree may have grown. A new extension may have cut across the old route. The survey checks the dome, the tube, the flashing and the ceiling end together, and tells you whether to replace like for like or to move.
We install and replace. Either way, the work is finished neatly, inside and out.
Planning, paperwork and the next step
Fitting a sun tunnel is usually a small job on the roof, but it is still building work. Installation meets current Building Regulations, and any Building Control notification the work requires is handled by us. Whether planning permission is needed depends on the house and the roof, and the planning guide at skylight planning permission in Milton Keynes is the place to start. If you are unsure whether your street has special rules, ask the local planners before you order.
After that comes a free survey. The room, the roof and the loft all get a look, the run is measured, and the choices are talked through. The quote you get is fixed and written, with no change on the day, and a 10-year workmanship guarantee in writing goes with the work. A typical fitting takes one or two days.
For the cost side, read what moves the price of a sun tunnel. For the light itself, see the daylight answer, or what a sun tunnel is if you are starting from the beginning. When you are ready, book your survey.
Placement questions answered
Which room is best for a sun tunnel?
A small room with no outside wall and a roof or loft above it. A landing, a bathroom, a hallway or a walk-in wardrobe suits a tube well.
Can a sun tunnel light a ground-floor room in a two-storey house?
Only if there is a short, workable route to the roof. If other rooms sit above, the route is often too long, and a different kind of glazing elsewhere may do more good.
Do I need a view or only light?
A sun tunnel gives light only. If you want a view or an opening for air, a roof window is the right tool, and the survey can compare the two.
