We supply and fit sun tunnels in Clerkenwell for halls, landings, bathrooms and other rooms that get little or no daylight. If you have a dark space with a loft or roof void above it, this page is for you. It explains how a sun tunnel works, the sizes and parts, how we fit one and what drives the cost.
A sun tunnel is a small dome on the roof linked to a round diffuser in the ceiling. A tube with a mirror lining carries daylight down between the two. The result looks like a light fitting, but it is lit by the sky. Our fitters are FENSA registered, and the work comes with a 10-year guarantee.
Sun tunnels are part of our wider double glazing service in Clerkenwell. You can compare them with other roof glazing on our main skylights page.
How a Sun Tunnel Works
There are three main parts:
- The roof dome. A clear dome sits on a flashing on the roof. It catches light from across the sky, not just direct sun.
- The tube. The inside has a highly reflective lining. Light bounces down the tube with very little loss.
- The ceiling diffuser. A frosted panel in the ceiling spreads the light evenly across the room. It looks neat and hides the tube.
Light still comes through on a grey day, though it will be softer. At night, the diffuser is dark, just like a window. Some kits include a light fitting inside the diffuser, so one unit lights the room by day and night.
Rigid and Flexible Tubes
There are two types of tube. The choice depends on the route from roof to ceiling.
- Rigid tubes are straight sections with a mirror finish. They carry the most light, so they suit long runs and larger rooms. Angle pieces can steer the tube around rafters or pipes.
- Flexible tubes bend around things in the loft. They are quicker to fit but lose more light along the way. They suit short runs of a metre or two.
Tubes come in a range of widths. A smaller tube is fine for a WC or a cupboard. A wider tube suits a hall, landing or kitchen. We pick the size at the survey based on the room and the length of the run.
Where Sun Tunnels Work Best
A sun tunnel is a good choice when a full window is not possible. Common places include:
- Halls and landings in the middle of the house.
- Bathrooms and en-suites with no outside wall.
- Walk-in wardrobes and utility rooms.
- Kitchens at the back of a deep terrace.
- Single storey extensions with a pitched or flat roof.
They work on most roofs, including tiled, slated and flat. On a flat roof, the dome sits on a raised kerb so rain runs away.
If the room sits right under the roof slope, a roof window may give you more light and fresh air. See our page on Velux windows for loft rooms and vaulted ceilings. For period homes where the roof must keep its look, our conservation rooflights are worth a look.
How We Fit a Sun Tunnel
We start with a free survey to plan the route from roof to ceiling. You then get a written, fixed quote. Our full process, from survey to aftercare, is set out on our how we work page. On the day, the steps are:
- We mark the ceiling and cut a neat round hole between the joists.
- We find the matching spot on the roof and lift a few tiles or slates.
- We fit the flashing and dome, then make good the tiles around it.
- We join the tube sections in the loft and seal each joint with tape.
- We fit the ceiling ring and diffuser, then clean up.
Most sun tunnels are fitted in half a day. There is little mess inside, as most of the work is in the loft and on the roof.
What Drives the Cost of Sun Tunnels
We do not list prices online. Each job gets a written, fixed quote after a free survey, and you can book one on our get a quote page. The cost depends on:
- Tube width. Wider tubes let in more light and cost more.
- Tube type and length. Rigid tubes and long runs need more parts.
- Roof type. Tiles, slates, felt and metal roofs each need a matching flashing.
- Extras. Built-in lights, extractor fans and dimmer kits add to the cost.
- Access. A tall house or a steep roof may need scaffold.
- Number of units. Fitting two or three on one visit saves time per unit.
Payment stages are set out in your written quote.
Planning and Building Regulations
A sun tunnel has a low dome, so most fall under permitted development. Rules are stricter for flats, listed homes and homes in conservation areas. If that applies to you, check with your council first.
The tube passes through the loft, so it must be well sealed and insulated. This stops warm, moist air from reaching the cold roof space. A sleeve of insulation around the tube helps cut heat loss and stops condensation forming on the outside.
Care and Upkeep
Sun tunnels need almost no care. The tube is sealed, so dust cannot get in. A few simple checks each year are enough:
- Look at the dome from the ground. If leaves or moss have built up, have it cleaned.
- Wipe the ceiling diffuser with a damp cloth.
- Check the loft for any sign of damp around the tube.
The dome is made from tough, UV-stable plastic. It will not yellow or crack with normal weather.
Sun Tunnels in Extensions and Orangeries
A sun tunnel can also help the room next to a new extension. When you build out at the back, the old kitchen or dining room can lose its window light. A sun tunnel through the main roof can bring it back. For the extension itself, a glass roof or an orangery with a lantern lets in far more light.
Frequently Asked Questions
Can sun tunnels be installed in any room?
Most rooms on the top floor, or in a single storey extension, can have one. The tube needs a clear route from the roof to the ceiling. In a two storey house, a ground floor room can sometimes take one through a cupboard upstairs. We check the route at the survey. Rooms with a flat roof or a pitched roof both work.
Are sun tunnels suitable for flat roofs?
Yes. On a flat roof, the dome sits on a raised kerb or an angled base so water runs off. We seal the roof covering to the kerb in the same way as a flat roof skylight. A short tube on a flat roof extension can bring a lot of light into the room below with very little loss along the way.
Do sun tunnels provide ventilation as well?
A standard sun tunnel brings in light only. Some kits include a fan that pulls air out through a vent in the diffuser. This suits bathrooms and en-suites with no window. The fan needs a power supply and must meet Building Regulations for extraction. We can talk through the options at the survey.
How much light does a sun tunnel give?
It depends on the tube width, the length of the run and the weather. A short, wide rigid tube on a bright day can light a hall or bathroom as well as a ceiling bulb. On a dull day the light is softer but still useful. Longer runs and flexible tubes let through less light. We size the tube to suit the room.
Will a sun tunnel make the room cold?
No. The dome and diffuser trap still air, and the tube is wrapped in insulation where it passes through the loft. This keeps heat loss low. The ceiling diffuser seals the hole, so there are no draughts. Some diffusers have a double layer for extra warmth. The tube is sealed at every joint to keep the loft dry.
