Sun Tunnel And Natural Light

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What is a Sun Tunnel or Solar Tube and how does it work?

Sun Tube, Sun Tunnel, Sky Tube, Solar Light Tube, Light Tunnel, and Solar Tube, a lot of different names for same thing, made by different manufacturers, but they all achieve the same purposes. All of the above capture sunlight or daylight and transmit it down either a solid reflective aluminium tube or a shiny flexible ribbed plastic tube in the least number of bounces possible.

How Sun Tubes Work

Either a flexible or solid tube directs natural light or ambient light through the tunnel to a diffuser (opaque double glazed ceiling tile) which can be positioned on your ceiling where the light is required.

Sun Tunnel

Do They Do What It Says On The Tin?

Layton Roofing & Building Specialists have been fitting them for many years. The results can be very surprising even if you’re used to seeing the before and after results. If you have been installing sun tubes for a living like Layton Roofing do it can often be a difficult balance to advise a customer on how good a sun tube will be without either overselling it and setting up for a disappointment, or under selling and putting a client off unnecessarily. No one wants to see an unhappy face after the completion on a job, and so far everyone has been pleased with the results.

Which Manufacturer Of Sun Tunnel Is The Best To Use?

If you have been trying to find sun tunnel reviews or compare them it can be almost impossible to get like for like figures for light levels, brightness or light output in watts. So if you’re thinking of fitting a solar tube or sun tunnel, I bet you’d like to know two things in the most uncomplicated way possible…

  • How much light will I get from a sun tube
  • Which sun tube should I buy

Important questions, and I will try to answer in the simplest possible way. Over the years I fitted a few different brands of sun tube that employ slightly different strategies for capturing light, and they will all argue with percentage figures to back them up that their system is the best. This can make choosing a sun tube quite confusing. I can honestly say though they are all fairly comparable to the naked eye in my opinion, were probably talking a few percent difference like for like. Could you tell the difference between a 100 watt bulb and a 110 watt bulb if you couldn’t switch between the two? No neither can I, but keep reading and well go through the important factors in getting the brightest sun tunnel possible.

How Much Light Will You Get?

This really depends on a few factors but here are the main ones…

Position –  Can you sit it on a south facing roof? This will obviously harvest the best quality of light and is desirable, but a sun tunnel doesn’t have to face south as ambient light will still make quite a difference.

Length of sun tube – What is the length of the tube required internally to transfer the light from the underneath of the roof to the ceiling where you want the diffuser to be fitted. The longer this tube the more “bounces” the light has to make to reach its destination and therefore the more.

Which Is Best, Rigid Or Flexible?

Flex tube iconFlexible tube – Most suited to shorter distances, normally 1.8 meters or less ( 6 feet ). Although cheaper to purchase and install because of faster fitting and a cheaper purchase price, the slightly crinkly reflective material will loose more light in a long tunnel. This is because the minute creases in the flexible tube bounce the light around a lot more than it’s rigid counterpart. Having said that, if you’re south’ish facing and don’t require more than 1.8 meters in length it can produce very good results.

Rigid tube iconRigid tube – The best option if you are looking capturing the most light possible, if you have a long distance between the roof and the ceiling, or maybe if you cannot fit a sun tunnel on a south face and need to capture the most ambient light. Rigid sun tunnels are really essential for a sun tube length over 2 meters as you will loose a lot less of the captured light.

Sun Light Tube Output In Watts

Lets Assume You Are Fitting A 12″ to 14″ Sun Tunnel ( 30cm to 35cm )
In the average suburban house with an average ceiling height of 8 to 9 feet ( 2.4 to 2.8 meters ) you can expect the sun tubes lights to illuminate an 8 foot by 8 foot area quite well depending on the factors mentioned above.
Cube2Sun tube lighting – An 8′ x 8′ x 8′ cube, lets call this the sun tubes ‘Footprint’ I will now do my best to describe how many watts of light you will get if you were to stand not underneath the sun tunnel but just outside it’s footprint in comparison to a light bulb doing the same job. I have chosen 8 x 8 because this will give you a practical indication of light and area.
Let me explain further, if you put a 100w bulb in a small box room it would be bright because the light reflects off all surfaces and illuminates an area. Now imagine the same 100w bulb inside a pitch black aircraft hanger, now the bulbs illumination would look very bad. Even though it’s the same bulb and wattage.
Now rather than complicate matters about how many degrees to the south or not your house faces, whether its spring or summer or which country you live in, lets just split it up into two camps, ambient light and sun light in spring or summer. I realise this is less technical, but it will probably provide you with more realistic light levels unless you are familiar with the complications of Lux and Lumen.
Ambient light – Lets call this an average non sunny day or a house where the suntube  is not positioned facing south, here are the light levels you can reasonably expect.

  • Flexible tube – 2m = 40 – 60 watts
  • Flexible tube  – 1m = 60 – 80w
  • Solid tube – 2m = 80 – 100w
  • Solid tube – 1m= 90 – 110w

South facing sunlight – The ideal sun tunnel install that will supply the perfect light for a sun pipe to fulfil its potential.

  • Flexible tube – 2m = 80 – 100 watt
  • Flexible tube – 1m = 100 – 110w
  • Solid tube – 2m = 150 – 200w
  • Solid tube –  1m = 150 – 250w

Solar tube review of light output
Rather than lots of pictures to click into and back out of, here I have compiled a video of sun tube installations. They show Velux sun tunnels and Solatube sun tunnels installed in the home in various locations, both Flexible and Rigid.

Before And After

It is difficult to how to explain how much actual light you can expect from a sun tunnel, and can be hard to articulate unless you have fitted quite a few in different situations and seen the effect first hand. This is quite a good day light calculator from Velux – Velux sun tunnel calculator and provides light levels in Lux.

f you have been reading sun tunnel reviews or trying to compare solar tubes, it can be quite difficult. I have fitted two or three different brands for customers who have specified a specific make or model and apart from size, and tube type i.e. flex or rigid it’s almost impossible for me to tell them apart. I would say however go for a well know manufacturer as this will ensure quality and spare parts should something get damaged.

Compare Sun Tunnel Manufacturers

  • Velux Sun Tunnel
    Probably the best know maker of sun tubes a very good constantly updated and improved product, and simple to install in most circumstances. Velux flexible tube or rigid options available in 10″ and 14″ ( 25cm or 35cm ) and the Flat roof sun tube. See the product on their page Velux sun tunnels
    Velux badge

  • Solatube
    Another quality sun tunnel company with some innovative features such as the ‘ Raybender ‘ and ‘ LightTracker ‘ technologies, designed to capture more light than other sun tubes. Available in 250mm and 350mm diameter tubes.See their product pages Solatube sun tunnels
    Solatube ico

  • Fakro
    Again, another high quality sun tunnel and roof window manufacturer with a history of good quality products, and now growing in popularity in the UK.See their product pages Fakro sun tubes
    Fakro sun tunnel

  • Solarspot
    A brand I haven’t come across until now if I’m to be honest, but one again promising to be brighter than the competition. I’m sure its a very good tube feel free to research it and look for reviews.See their product pages here Solarspot tubular daylighting systems
    Solarspot sun tunnel

If you are interested in having a Sun Tunnel fitted by a professional then look no further. Layton Roofing & Building Specialists have been fitting sun tunnels for many years and have many satisfied customers. Please contact us for your free no obligation quote


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