Lightway, all smoke and Bohemian glass mirrors?
Lightway sun pipe’s marketing seems very impressive but when we’ve tried to drill down to find out some facts and figures, to back up the big claims, we’ve run into a bit of a wall.
Lightway actually approached us at Norflo over the summer of 2015 with the aim of bringing us on board as a Lightway installer but were unable to answer even the most basic questions that were posed to them. A solar tube is a fairly straight forward piece of kit to evaluate. It has a limited number of basic components and it should be relatively straight forward to size-up, and yet, all of our questions seemed to cause some consternation with guys at Lightway.
So let’s take a look without them.
They make a big play about the dome and how it’s made from Bohemian Crystal. They then lay into domes that are made of thermoplastic because; (alledgedly) they get dirty, they discolour, they don’t look as good on the roof and they gather less light. This is not what we’ve found.
In terms of dirt, the dome is shaped in such a way that any atmospheric dust and grime is washed off by the rain. We’ve found this to be the case in all of the systems that we’ve fitted. Discolouring is a problem and continues to be evident on the Solatube which is one reason why we no longer recommend them. We suggest looking out for acrylic or PMMA domes. As for the appearance on the roof, that’s a matter of opinion, after all, beauty is in the eye of the beholder. incidentally, Lightway themselves use PMMA on their larger systems so I think there’s some slight disingenuity going on here.
And whilst I’m on the subject; I’m a man who likes things to be simple. If I see a product that has a name or number I like it to have a clear meaning. When you see a product called an LT400, LT300 and LT200 you’d expect the numbers to relate to the procduct. For example, the Sunpipe 450 is 450mm in diameter, the Solarspot D-25 is 250mm in diameter but the Lightway 400 is actually 320mm in diameter… buyer beware. I’ve also seen enough solar tubes installed to know that the LT200, a tube that is less than 160mm in diameter, will not light an area much larger than a shoebox.
In terms of the claims for light capture and efficiency – there’s absolutely no science behind any thing that they are saying.
Firstly, glass actually isn’t necessarily better that materials like plexi-glass. Whilst glass has very good optical properties, it isn’t a particularly good light transmitter when compared to plexi-glass. The main problem with glass is that it needs to be quite thick to be strong enough to be used on a roof in this way. The thicker the glass, the more light it will absorb – that’s not good. In fact, in some recent testing the efficiency of the thick glass dome was measured at only 0.50. This compares very badly with systems like Solarspot and their dome, which has a measurement of around 0.90.
- Secondly their dome has no light capture technology in it so that won’t help either. Bohemian crystal does make a nice fruit bowl but on a roof in a building site environment, no thanks. Ironically, on their larger systems they revert back to PMMA plastic like Solarspot use for their domes – Come on Lightway, pick a story and stick to it.
The same is similar with the tube material. There’s quite a bit on their website attacking Solatube (or American sun tubes as they call them) tube lining. They claim that they can bubble or delaminate. We have to say that this is not our experience and would feel more confident about a material that has been in use for over 12 years than some new product that seems to have no technical data to support it. There does not appear to be any evidence available of how reflective it actually is.
They also claim 99.8% reflectivity. But when you read their small-print, is actually says that the reflecty value is 98% at 45 degrees. So it’s 98% reflective, like Velux and Fakro, and not a super-reflector like Solarspot and Solatube.
Personally we think the Lightway unit is all smoke and Bohemian glass mirrors but we’re happy for someone at Lightway to send us all of their technical data so that we can amend the information above.
- Lots of lovely brochures and a great website
- The dome would be great for storing your Quality Streets in at Christmas
- No supporting technical data what so ever – make up your own mind