Sun tunnels: What is a sun tunnel and which sun tunnel is right for me?


What is a sun tunnel?

Sun tunnels are an inexpensive solution to bringing light into a home where there is limited space for a rooflight. They feature a panel that sits discretely on the outside of a roof, a highly reflective tube channeling sunlight into the room, and a diffuser that disperses light naturally.

Sun tunnels can be installed on both flat roofs and pitched roofs, providing a good all-round solution for dark bathrooms, loft spaces or small home offices. They are also beneficial in hallways and corridors, reducing electricity bills by introducing natural sunlight. This product can pay for itself!

Which sun tunnel is right for me?

Because they suit such a variety of needs, there are a number of options when it comes to picking which sun tunnel is right for you. The first decision when buying a sun tunnel is whether to choose a flexible sun tunnel or a rigid sun tunnel. This will depend on where you’re aiming to direct light and what will it will need to pass through:

Rigid sun tunnels

Rigid sun tunnels consist of one straight tube to direct light where you need it. These tunnels can’t be bent or angled but will give you the most light transmission as the light travels in one motion to reach its destination. Rigid sun tunnels are the most common choice for applications where the tube is installed through an empty roof space into rooms below.

Flexible sun tunnels

Flexible sun tunnels incorporate a bent or angled tube, reducing the amount of light that enters a room. However, because of the way that light bounces off the reflective insides of the tube, you can get around any obstructions that prevent you from using a rigid alternative. For example, if your loft space features aircon units or services, you can get around these with a flexible sun tunnel.

Flexible sun tunnels are best suited to shorter distances, allowing you to pick the optimum placement on the outside of the roof and to direct the tube exactly where you’d like it, even if that positioning isn’t directly below the roof.

What size sun tunnel do I need?

Sun tunnels come in many sizes made for either slate, tiles, or flat roof substrates. To ascertain the correct size of sun tunnel you need, it’s best to first look at where and why this is being installed. For example, will the light become a design feature, e.g. do you want to install the sun tunnels in an evenly spaced row or in a symmetrical pattern? Do you simply need one sun tunnel to light a small, dark corridor?

For applications where you’re lighting a small room then it is recommended to purchase the biggest product that will fit in the ceiling space. For larger rooms such as spare bedrooms or bathrooms then one or two medium-sized tunnels will be an attractive feature.

Room Size Example Room Type  Recommended Sun Tunnel Diameter 
0 – 4m2 Hallways, larders, walk-in wardrobes, and bathroom ensuites 10 inches
4 – 10m2  Small rooms, stairwells, and home offices  10 inches
11 – 15m2 Bathrooms and bedrooms  14 inches
16 – 22m2  Kitchens, living spaces and extensions 14 inches

How much light will a sun tunnel provide?

The amount of light a sun tunnel provides is dependent on several factors. This includes whether your roof is south-facing, from which it is possible to generate the most amount of light. If your roof doesn’t face south, this isn’t a problem as sun tunnels are highly reflective and provide good levels of light all round. Another factor that will determine the amount of light is the shape and size of the room. If, for example, you opted for a smaller, 10-inch diameter sun tunnel in a 20m2 room, the light dispersion will not be sufficient to light the whole area.

In the best, south-facing conditions, a rigid sun tunnel of 10 inches will provide around 150-200 watts of dispersed light compared with a 14-inch option, which will generate around 200 – 250 watts.


What brands of sun tunnel are there?

Sun tunnels are also known as light tunnels, light tubes or sun tubes and many popular brands are available. Choose between VELUX pitched roof sun tunnels and flat roof sun tunnels, FAKRO pitched roof light tunnels and FAKRO flat roof light tunnels as well as Monodraught sunpipes, Em Tube pitched roof skylights and Em Tube flat roof skylights.

If you need advice for choosing the right sun tunnel for your project, please contact our helpline on 01752 692 760.

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