A solar tube system is only as good as its dome
The RIR® (Refractive Interactive Reflection) Light Funnel captures more light!
Solarspot Dome Technology – If the dome, or covering, does not capture the maximum amount of daylight available then how can it deliver the maximum amount of light to your room. All Solarspot domes are precision moulded from non-yellowing impact resistant acrylic to provide maximum light transmittance, 95%, the highest on the market.
Compared this to the efficiency of some polycarbonate domes from companies like Solatube and you may be surprised to hear that they are as low as only 74% efficient. Solarspot domes meet all building regulations for fire.
You may be told that you must have a polycarbonate dome on your roof to meet these regulations but this is only the case if the dome (glazed area) exceeds a roof to glazing ratio of 5:1. In order to achieve this figure you would need to fit over 40 D-25 systems into the roof of a 10sqm room, when you would only require one.
Unlike any other system on the market, every Solarspot has active light capture technology mounted in the top of the tube harvest the maximum possible available daylight.
Acrylic, PMMA or Plexiglass as it’s sometimes known has a much greater light transmittance than polycarbonate. In addition, polycarbonate is not stable when exposed to the UV rays present in daylight. Read more…
Independent tests from the BRE have shown that domes from companies like Solatube go cloudy and yellow in as little as four years, reducing an already poor performance by a further 10%.
The patented RIR® technology works in three ways
Low level light – early morning and later in the afternoon, is redirected into the tube at a steep angle to force it through the tube more efficiently so less energy (daylight) is lost.
Direct, overhead light – the RIR ‘funnels’ the light to maximise its passage through the tube without obstructing and light as happens in moulded domes – as with Solatube and Sunpipe.
Over-cast days – light hits the dome from all angles so the RIR allows light from behind the dome to pass through whilst changing the angle to improve efficiency even more.
At the beginning and end of the day, and during winter months, light hits the dome from a low angle. The RIR® captures this light to ensure that the system is delivering the maximum performance all day long and throughout the year. The RIR also has the same effect when the dome is mounted on a north-facing roof, capturing light that is lost on other systems.
When the sun is above the vast majority of the light passes straight into the mouth of the tube whilst direct light that hits the back of the dome is captured and reflected in by the RIR® for maximum efficiency.
On cloudy days, light hits the dome from all angles. The crystal-clear dome and RIR® lens combine to ensure that the maximum amount of light is captured regardless of the conditions helping to guarantee more light into your home than any other light pipe system.
Not everyone had the luxury of a south-facing roof. This is no problem for the Solarspot as the RIR® lens captures light that casts across the roof and redirects down into the tube, and room below. This means that even north facing rooms can be bathed in beautiful, direct sunlight.
Condensation protection and thermal efficiency
An element of condensation is present in all solar tube systems but unlike all other systems that deploy their double-glazed lenses at the bottom of the system, allowing for potential condensation to form on the inside of the tube wall, the Solarspot condensation lens (Convas) is located at the top of the tube. This means any condensation that does form is restricted and managed in the dome without any risk of contamination of the tube wall.
Another benefit of the Convas lens is to increase the thermal efficiency of the unit by providing an air-tight seal and creating a triple-glazed system. In addition, the Convas lens provides another layer of protection for the reflective tubing, which can be damaged by UV rays if they are not screened out.
Frequently Asked Questions
Are the systems double glazed – and if so where?
All Solarspot systems are double-glazed just below the dome, and for good reason. Firstly, this acts to trap air in the tube to limit and heat gain or loss from the room below. Secondly is prevents any condensation, a natural situation that occurs in all solar tube systems, from getting into the tube itself. The Convas™ lens in the Solarspot contains any condensation, that may occur in cold weather, inside the dome and allows it to escape harmlessly onto the roof, unlike systems that are ‘double-glazed’ at the ceiling where condensation can actually get in the tube and onto the reflective surface.
Can I have two tubes coming down from one roof dome?
Whilst it may seem desirable to limit the impact of the number of domes on a roof by spurring off a number of tubes from one source it simply isn’t practical or effective. It would result in complicated configurations of longer tubes that result in a very inefficient system. As with many things in life, keeping it simple will give significantly better results.
Acrylic or polycarbonate, what is the difference?
You will see both materials being offered by solar tube manufactures. Polycarbonate is very strong and offers some advantages when particular specialist fire standards need to be met – specific commercial situations only (contact us for details). But polycarbonate has two disadvantages when compared to other materials; it has a relatively poor transparency rating and, rather alarming for a product designed for outdoor use, it goes cloudy and yellow when exposed to UV in as little as 12 months. Acrylic, also known as Plexi-glass and PMMA, on the other hand has most efficient light transmittance factor being even better than glass. It’s also strong enough to withstand the rigours of whatever the weather, or a clumsy builder, can throw at it. Read the acrylic vs polycarbonate summary of the BRE test
What about glass, Bohemian crystal to be precise?
If you are considering a Lightway sun pipe system you may be tempted by the claims made by their Bohemian glass dome. But dig a little deeper and the only thing Bohemian glass seems to have going for it is; it stays clean (well so does any dome shaped lens on your roof, regardless of what it’s made of) and it doesn’t go yellow (just like Acrylic). But glass, Bohemian or otherwise, has disadvantages. Firstly, despite what you might think, glass is not as transparent as some other material – acrylic in particular. The second, and probably more important, is that to withstand life on a roof it needs to be very thick when compared to plastic domes. In fact, the Lightway Crystal sun Tunnel dome is roughly 400% thicker than an equivalent sized plastic dome which consequently absorbs precious daylight that then doesn’t get through to the tube system.