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solarspot versus solatube

Are you considering buying a Solatube 160DS or Solatube 290DS?

Solarspot vs Solatube, how do you choose the best sun tunnel? 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 solatube 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.

The Solarspot 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 Solarspot D-25 over a Solatube 290 DS and save around £125. Comparing the D-25 and Solatube 160 DS, the Solarspot solar tube unit delivers 70% more light for, on average, less money. 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.

The Dome

Solarspot vs Solatube, which dome is better? 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 designed 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.

Solarspot dome

The Solarspot Dome

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

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

Solatube Dome

The 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.

The Tube

Whilst both are 99.7% reflective there’s an important 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.

solarspot tube widths 380mm and 335mm

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

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

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


Solarspot D-25

solatube 160 DS comparison to Solarspot D-25

Solatube 160 DS

Solarspot vs Solatube, which is brighter? These photos compare 250mm diameter light tubes fitted in neighbouring bathrooms in Milton Keynes.  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 systems 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. This allows them to maintain their BBA certificate but as there are no building regulations specifically for sun pipe style systems. To find out more, visit our FAQs page.

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 ratio of a sun pipe style system on a typical roof would be near to 500:1 so it doesn’t even come close.

Fitting Solarspot dome

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.

BBA certification and what it means to you

Dome datasheetIf you are a national house builder, you need products to have a BBA certificate to include them in the NHBC 10 year warranty. If you’re not, then it means absolutely nothing. It is a certificate of conformity which means that when it says the tubing is 99.7% reflective, or the flashing is made from powder coated steel, then it is.

Is it a guarantee of how good it is or how it compares? The answer is no.

Just to give you a comparison, the Solarspot dome had a transmittance figure of 94% and only showed a 1% loss in the four year period. Overall the Solarspot dome was around 30-45% more efficient than the Solatube depending on the life of the unit.

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

At Solarspot we have a coveted ISO 9002 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.

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

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