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Solarspot vs Solatube

If you are also considering a Solatube 160DS or Solatube 290DS

We can categorically prove with independent testing (ironically endorsed by Solatube themselves) that the equivalent products from Solarspot will give you around 70% more light – based on 2m tube. These tests were carried out by the BRE (Building Research Establishment) and CSTB (the European equivalent) and are independent and irrefutable. Read the report or skip the boring stuff and see a summary.

How can two systems, both with 99.7% reflective tubes, be so different?

It’s all about the design. The amount of daylight that gets into your room is due to two main components; the dome and tube. Starting with the dome, the Solarspot dome is designed to capture as much low level light, early morning, late afternoon and on cloudy days via the RIR light funnel whilst allowing the maximum overhead light to enter the system without any restriction or encumbrance.

Bizarrely, the Solatube dome is actually deigned to restrict light from above – or in their words - technologies incorporated in the Solatube roof dome help control light delivery to prevent potential glare during summer months… These ‘technologies’ are so effective that they can cut out up to around 50% of the potential light that could be lighting your home.

The other difference is the tube widths, whilst Solatube claim that their units are 250mm and 350mm in diameter, the extension tubes on these systems are only around 235mm and 335mm. Compare this to Solarspot extension tubes that are around 260mm or 380mm for most of the length of a system and you can see how the extra tube volume of our systems will allow a more efficient transfer of light.

Ask yourself one question, if this isn’t true, would be allowed to say it?


These photos compare 250mm diameter light tubes neighbouring bathrooms in Milton Keynes. Acrylic versus polycarbonate dome. The Solatube system had been installed for around four years and the dome had degraded so badly that it was only delivering around 25% the light of the Solarspot. In testing of new systems the Solarspot was delivering around 70% more light than the Solatube.

It starts with the domes

All Solarspot domes are supplied with acrylic domes because acrylic is a more light efficient material and doesn’t go yellow and cloudy when exposed to UV light. Now Solatube, who prefer polycarbonate, might try and tell you that there is an issue with acrylic and building regulations however this is not the case. Let us explain.

There are no specific building regulations written for sun pipe systems. There are however regulations written for traditional roof lights, and this is what Solatube have chosen to follow and highlight. To summarise a very long document, for a dome (or roof light) to be required to be made from polycarbonate, the area of ‘glazing’ would need to exceed a ratio of 5:1 (roof to glazing). The average ration of a sun pipe style system on a typical roof would be near to 100:1 so it doesn’t even come close.


The BRE test of Solatube domes

In a separate test commissioned by Monodraught Sunpipe, the BRE tested the light transmittance (efficiency) of their own dome (Sunpipe) against the Solatube Raybender 3000 with ‘Light Tracker’ reflector. In the tests, the standard Sunpipe dome was shown to be 15% more efficient than the Solatube – those patented Fresnel lenses where certainly doing a great job at keeping out all of that troublesome daylight. In a second part to the test, they looked at the UV effect on polycarbonate domes and the results were rather alarming. In as little as four years, the Solatube polycarbonate dome was proven to degrade, turning cloudy and yellow, to point where it had lost a further 10% of an already poor initial efficiency.

The answer is no

At Solarspot we have a coveted ISO 9001 certification that does the same thing. Every stage of production and material sourcing is tracked and recorded so you can be assured that every Solarspot system is manufactured to the same standard using the highest quality materials. Solatube Highest Performance Guarantee.

Up until August 2017, Solatube offered a ‘Highest Performance Guarantee’ on their ‘Brighten Up Series’ but since the intervention of UK Trading Standards and the Advertising Standards Authority it has had to be removed. The ‘money-back guarantee’ was judged to have testing criteria that was so convoluted that it could not be fulfilled and therefore it would be impossible to make a successful claim against.

Solarspot D-38
Solatube 290 DS
Solarspot D-25
Solatube 160 DS

The D-38 is the clear winner delivering around 70% more daylight than the D-25 or Solatube 290 DS. That means you could specify a 1.8m D-25 over a 290 DS and save around £125. Comparing the D-25 and 160 DS, the Solarspot unit delivers 70% more light for, on average, less money.

solarspot dome

Above the Solarspot dome harvests the maximum daylight into the tube, regardless of the weather conditions.

Solatube dome

The Solatube dome, whilst effectively harvesting light in the early morning and evening, actually restricts light from overhead both on sunny and overcast days, as well as blocking light from the north.

On average, the Solarspot dome captures 50% more daylight than the Solatube.

Solarspot extension tubes

Size for size Solarspot extension tubes are around 20% more efficent than Solatube*.

*Due to the extra width Solarspot are able to deliver more light as it can travel through the tubes more efficiently.

BBA certificate

A BBA certificate offers no guarantee of product performance. In fact, up until a few years ago, the worst product ever tested held a BBA certificate.

ISO 9001

Solatube are no longer able to offer this guarantee following a ruling by trading standards.


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