Sun Tunnel Buying Guide

Updated August 2025

Brighten up areas of the home that natural light struggles to reach with a sun tunnel or two.

Sun tunnels, also known as light tunnels, are a practical, cost-effective way of introducing the benefits of daylight to spaces as small as cupboards and as big as bedrooms.

Healthier than artificial light and cheaper than roof windows, sun tunnels are an increasingly popular lighting solution for residential and commercial properties alike.

*VEW sun tunnels also come with a FREE electric light kit which easily connects to the sun tunnel to be used in the evenings and nights.

Should I Buy a Rigid or Flexible Sun Tunnel?

Sun tunnels come in two distinct reflective tube designs, rigid and flexible. Both have their own advantages.

Rigid

Rigid sun tubes provide sunlight with a direct path from roof to room, meaning less light bounces off the tube's surface and more makes its way into the room.

The pricier of the two tube types, rigid sun tunnels can offer up to 20m of light distribution, meaning light can go a lot deeper into a room and brighten those harder to reach areas.

To help negate obstacles in the roof, adjustable elbows can be easily fitted to existing tubes, as can extension tubes to allow natural light to travel further.

The VELUX Group supplies rigid sun tunnels in two different diameter widths for slates and tiles, and for both pitched and flat roofs.

Flexible

Flexible tubes are great for negating around obstructions in the roof space as they can be easily manipulated to bend around the existing building work.

Flexible sun tunnels are ideal for shorter distances and are the cheaper of the two options. The difference in price is mostly down to flexible tubes reflecting slightly less sunlight as rigid tubes.

Flexible sun tunnels are available from VEW, in 3m tube lengths that can be easily cut to 2m.

The VELUX Group's flexible sun tunnels come with a diameter of 35cm and 2m long tube for slate and tile roofs.

What Size Sun Tunnel do I Need For My Room?

Deciding on what size sun tunnel you need all depends on room type. For the best results in medium to large spaces, we recommend installing either one or two bigger sun tunnels or a cluster of smaller tunnels.

23-25cm

Room Size- 4-10 m2

Room Type- Hallways, small bathrooms

32-45cm

Room Size- 11-15 m2

Room Type- Large hallways, stairwells, bathrooms

52-55cm

Room Size- 16-22 m2

Room Type- Kitchens, bedrooms, living rooms

Can Sun Tunnels Work on any Roof?

Yes, they can, and not just roofs either. As well as being compatible on both pitched roofs and flat, sun tunnels are also available for installation on the outside of walls. Here is how:

Flat Roof

Sun tunnels are available for all types of flat roof pitches, installed with a flashing and flat roof upstand. Sterlingbuild's range of 35cm, 45cm and 55cm flat roof sun tunnels are available strictly with flexible tubes, either 2m or 3m long.

VEW sun tunnels come with an easy to fit diffuser, ceiling mounting ring and everything needed for a professional installation.

Offering both flexible and rigid options are the VELUX Group, who manufacture a 35cm sun tunnel in both tube styles.

Pitched Roof

VEW’s flexible pitched roof sun tunnels come in the same sizes as our flat roof sun tunnels and can be applied to both slate and tile.

The VELUX Group's flat roof offering consists of a 25cm and 35cm sun tunnel- one rigid and one flexible.

Remember to always bear in mind where the best place on your pitched roof is to position your sun tunnel.

Installing a light tunnel on the south-facing side of the roof will optimise the amount of natural daylight your tunnel can capture.

Walls

It is also possible to install sun tunnels directly into your wall with a side wall sun tunnel here. From brands such as Intura, you're guaranteed everything you need in an all-in-one complete package.

Extras

We have a number of additional accessories available at Sterlingbuild to enhance the scope and performance of your sun tunnel. Here are a few of our best.

Adjustable Elbows & Extension Tubes

To help you manoeuvre your rigid sun tunnel around roof construction, adjustable elbows can be purchased to be used with any sun tunnel size. Rigid VELUX sun tunnels can both be be made more flexible with the addition of elbows.

To expand the reach of your sun tunnel and illuminate rooms even further, extension tubes can be purchased from the VELUX Group.

For VELUX flexible sun tunnels, a 2m long extension can be added. The same is true for VEW Sun Tunnels.

Light Kits

A light kit is a handy accessory that can be easily fitted into your pitched roof sun tunnel post installation to make sure you can always turn on your sun tunnel - even at night.

Available from Power Daylight and VEW, electric light kits are one of the most popular accessories for sun tunnels. The kit fits seamlessly onto the existing tunnel for a space saving, highly practical design.

Most electric light kits, such as the VEW tunnel, are LED compatible so will not consume energy at nearly the same rate as incandescent bulbs