This article shows how ukbathroomguru used a sun tunnel (or suntube) to increase natural light in a new en suite that had no windows.


This article follows on from my previous article which dealt with ways to maximise natural light in en suites with no windows.

It deals with the installation of a sun tunnel as part of the overall en suite installation which can be seen in more detail here.

Sun tunnels effectively redirect light from your roof through your loft void to the room below, meaning that you won’t necessarily always have to turn the lights on.


They are an excellent way of getting natural light into an en suite or bathroom that has no window or opportunity for a Velux style window to be fitted (normally because there is a loft space above).

They work best over small straight runs and the amount of light they direct into the room below is quite surprising, as can be seen from the image below from Velux’s website.


Sun tunnels usually do not need planning permission but you should always do your own due diligence to find out, especially if you live in a listed building or conservation area.

Case Study: Sun tube installation

In this en suite there were no external walls, so there was no opportunity to fit a new window.

There was also a loft space above so a Velux type window could not be fitted in the roof.

Therefore it was decided that a sun tunnel could be fitted.

This is how it is done….


Loft insulation and boarding is stripped back and a hole is cut in the plasterboard ceiling of the bathroom below & loft timbers are moved out of the way as required. The suntube ceiling fixture is secured into place.


Roof timbers are amended & roof tiles removed to suit the installation of the domed external part of the sun tunnel. Flashing is fitted to ensure the roof remains watertight.

The two sections are then essentially linked together with the main body of the sun tube, which has a highly reflected inner surface to bounce light down into the room below:


All joints are taped with a reflective Aluminium tape to make sure as much light as possible makes it to the room below and is not lost into the loft.

The light produced is very bright and as Velux themselves say:

“Natural daylight brings your indoor spaces to life in ways that a simple lamp can’t. Experience the changing light of the seasons and times of day.”


Sun tubes can be fitted for between £500-£900 depending on location, and distance from the roof etc.

Extra features

Some sun tunnels can be fitted with the following additional features:

Blackout shade


I understand this is held in place magnetically, and can be fitted or removed in seconds.

Daylight controllers


Daylight controllers allow users to control the amount of daylight that enters the room with a remote control.

Some daylight controllers use an electrical outlet and some use solar power & internal batteries depending on the model / manufacturer.

This feature allows the skylight to be dimmed if you want to take a nap or reduce the glare on your TV, though neither of these features is generally applicable to en suites or bathrooms!

However I have read reports that the dimmer feature actually reduces the total amount of light coming through the sun tube by its very presence so read some reviews before purchasing.

Nightlight kit

Some sun tunnel models feature an additional light kit that is effectively a bulb fitted behind the diffuser as shown above.

Anything else?

If you have any questions or thoughts about this article or any others, please feel free to contact me  or leave a comment.