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How to choose a sun tunnel daylight system

Flexible Daylight Pipes Are No Match For Solatube Rigid Tube Systems 

We are often asked about the difference between Sun Tunnels that use flexible tube material rather than the rigid tubes used in Solatube Sun Tunnels. Are flexible tube systems easier to install? How efficient are they at transferring light from rooftop to the room below? Are they cheaper to buy? 

Lets starts with cost... 

Flexible sun tunnel systems can be cheaper than their rigid tube counterparts. If cost is the highest priority when purchasing a daylighting system rather than the system quality or light output, then you or your builder may opt for a flexible system. But are you really saving money? 
 
What if we told you that you would need 10 flexible light tubes to meet the light output of just one Solatube Daylighting system? This was the result when the Building Research Establishment* tested our Solatube rigid tube system – size for size – against the flexible tube system of the most widely-known roof light manufacturer. 
 

Ok, well, are flexible systems easier to install? 

We don’t think so; both system types require roof works and ceiling cutting, but to get the best light transfer from any tubular daylighting system, the tube should be as straight as possible with minimum bends.  
 
To make a flexible tube straight means that it must be tightly stretched and then fastened very securely at the top and bottom end of the system – which is very difficult to achieve in an actual installation. And, of course, flexible tube products are often chosen by builders because they need to bend them around obstructions in the roof, so the already-dismal light output suffers even more at every bend in the flexible tube.  
 
Remember, every Solatube system comes with two 0-30 degree angles incorporated in the top and bottom tube to make installation easier and additional 0-90 degree angles are available too.  

What about efficiency? 

As already mentioned, a single Solatube Daylighting System can provide more than 10 times the light of a similar sized flexible light pipe system. Our tube material plays a large part in the superior performance of the Solatube sun tube system; our rigid tubing use Spectralight Infinity 99.7% reflective tube material which transfers light evenly and efficiently down the tube to the room below.  
 
Unique to Solatube, this material loses only 0.3% of the light at each bounce down the tube. By contrast, a flexible tube, with its concertinaed foil lining, reflects light in all directions (including upwards!) resulting in very poor light output – see below. 
So while flexible sun tunnel systems may be perceived by some as the easier, cheaper option, they will never match the quality, light output and efficiency of a Solatube rigid tube system. In continental Europe, flexible tube systems are shunned owing to their poor performance and quality. In the UK, however, while the professional community rarely specify them, some homeowners and builders are tempted by a brand name or use them simply because they are readily available at builder’s merchants and cheap. 
 
If you want a quality, efficient tubular daylighting system that delivers high levels of daylight into your home, make sure you (or your builder!) steer clear of flexible tube systems! 
28 February 2017 
 
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