What makes us the brightest

See how our scientific approach delivers more light to you

Solarspot® – More efficient than the Solatube® or Sunpipe®

The BRE test results are in

Look at any sun tunnel suppliers’ website and they will probably tell you that their system is the best, the brightest, the most efficient etc. in order to persuade you to buy from them. So how do you know who’s telling you the truth and who’s leaving you in the dark when it comes to the facts?

To say that some manufacturers make claims that are open to interpretation is giving them the benefit of the doubt. A less charitable person might reach the conclusion that they are giving out false and misleading information. A couple of manufactures, who will remain nameless, are claiming to be ‘95% efficient’, when what they actually are is 95% reflective – not the same thing and the net result in terms of light delivery is massive. In fact, no system in the world is 95% efficient and systems with reflective values of only 95% are actually so poor that we discounted them in these tests.

It’s difficult for the average consumer to cut through all of the jargon and reach an educated and informed decision without the help of a qualified team of daylight boffins – and where can you find one of those when you need one? So in order to shed some light on the problem, we went to the independent daylight experts at the BRE and asked them for help.

Building Research Establishment

BRE (Building Research Establishment) is an independent and impartial, research-based consultancy, testing and training organisation, offering expertise in every aspect of the built environment and associated industries – that’s what it says on their website so who are we to argue.

We asked them to take our Solarspot D-38 system and compare it to a Solatube 290DS and Sunpipe 450 and test them to see which was the most efficient at delivering daylight – what other reason would you have to buy one and what critical information would you need when deciding which system to purchase? We also referenced a couple of the very popular (amongst builders and not necessarily the individual left with the rather poor results – more will be explained) flexible duct systems.

So why these systems and sizes?

There are many systems and sizes available and it would be impractical, and expensive, to test every single system and size on the market, so we picked the countries best-selling rigid system; the Sunpipe from Monodraught and the Solatube, apparently the world’s leading daylight system. The Sunpipe system has a diameter of 450mm and has a claimed reflective value of 98% whilst the Solatube has a diameter of 350mm and reflective value of 99.7%, so the Solarspot sits in between size wise.

All three systems were just over 2m long and the tests were carried out under a natural overcast sky – this is Britain after all. The tests were performed at the BRE’s headquarters in Bricket Wood in Hertfordshire.

The test results and what it means to you

Each system was tested three times to ensure that there were no spikes in light or freak results and the average of the efficiency of the three readings is given as the result.

As the table shows very clearly, the clear winner in efficiency terms is the Solarspot D-38 with results that are roughly half as good again as the other two. So what does that mean in terms of light delivery for you and your home.

Simply put, if you had two systems, side-by-side, in the same roof, facing in the same direction, and both tubes are the same length, then if one was half as efficient again as the other, then you would expect half as much light again as the other. But you also need to take into account the width of the tube.

For example; if you put a Solarspot D-38 and Solatube 290DS together – as suggested above – because the Solatube is 30mm narrower, it has less volume. In turn, the Solarspot would be delivering around 69% more light in the same conditions.

Flexible-duct systems

In tests previously carried out by the BRE for Solalighting Limited, (BRE test number 248038a) measuring the efficiency of two 350mm diameter flexible-duct systems, they were shown to be more flexible fiend rather than flexible friend (you have to be old enough to remember that reference).

The best figures that the flexible unit were able to return were only around 6%. This was with the ducting being pulled tight and with the tube completely straight. In reality the tube will not be totally straight and with some slack in the system; given this more realistic scenario the figures are likely to be nearer 1.5%-3%.

In conclusion

It’s clear to see that there is a resounding winner, and we hope that the winner is our customers. If you would like to read the full report from the BRE you can download it from our website, just follow the link at the top of the page.

If you would like more information about how Solarspot can transform your home with natural daylight, please call us today on +39 0332 700137 or use our email link.

System specifications as tested
Solarspot ® D-38* 375mm diameter, clear dome with RIR Light Funnel, single-glazed diffuser, Vegalux tubing; 99.7% reflectivity, 2280mm in length
Solarspot ® D-38** 375mm diameter, clear double-glazed dome with RIR Light Funnel and additional Convas lens, single-glazed diffuser, Vegalux tubing; 99.7% reflectivity, 2280mm in length
Solatube ® 290DS 350mm diameter, Raybender dome with Light Tracker reflector, double-glazed diffuser, Spectralight tubing; 99.7% reflectivity, 2280mm in length
SunPipe ® 450 450mm diameter, diamond dome, double-glazed diffuser, Supersilver tubing; 98% reflectivity, 2280mm in length

* This is the standard version of the system and is supplied unless specified.

** Convas lens option. For multiple installations in commercial roofs or building with ‘warm-roofs’ a Convas lens may be specified.