Be a Karen – not a Dick or a Dylan...
Karen did her research and got 70% more daylight with a Solarspot*
Dick spent more money and bought a Solatube but got 40% less daylight*
Dylan bought a Velux flexible sun tunnel – lucky he has a good torch*
Up to 70% brighter than the next best system*
Unless you have the opportunity to see them side-by-side it’s difficult to visualise the difference between one sun tube and the next. So to help illustrate this we’ve made a very simple comparison to domestic light bulbs.
*350 – 400mm sector.
The Science Behind the Solarspot
What makes Solarspot the brightest choice – we are the only manufacturer that publishes independent comparative test data that allows you to be able to see just how our system compares to the likes of Solatube, Sunpipe or Velux. So when we say that we’re brighter you know that it’s true.
For legal reasons we have to state that all independent testing is for your reference only and none of the testing companies involved either endorse or recommend any particular product or brand. So if you want to find out how the products you are considering compare, you should ask for the efficiency figure so that you can make a comparison.
Unlike virtually any other product a solar tube has only one function, to bring in daylight from the outside to the inside, yet most suppliers seem to offer confused information making it difficult for the customer to determine which manufacturer supplies the product that provides the most light.
The test results provided by Solarspot make it clear how a Solarspot compares to the so-called ‘leading systems’ on the market.
We tested the leading products in the 350 – 450mm category as it’s probably the most specified system size. For this comparison three 2.2m systems where passed over for testing.
The systems sent were the:
- Monodraught SunPipe 450
- Solatube 290-DS
- and our own Solarspot D-38.
All three units were tested in over-cast light, the scenario recommended as it provides a level playing field so that most accurate indication of the products performance can be measured.
The testers were then able to produce an efficiency figure for each of the system so that calculations could then be done to determine just how much light each unit will deliver (compared to another) regardless of external conditions, tube length etc. The Solarspot D-38 significantly out-performs the other two being 33% more efficient than the SunPipe and 44% more efficient than the Solatube.
Whilst the Solarspot D-38 is an impressive 44% more efficient than the Solatube 290-DS, it actually delivers around 70% more daylight. This is due to the slightly wider tube diameter of the Solarspot.
Probably the best selling product in this size category is the Velux 350mm flexible system. Using the same testing process, the Velux flexible unit was shown to have a meagre efficiency level of less than 4%. Compare this to the Solarspot D-38 with an efficiency of 57%, and a slightly wider diameter, and you would expect to get roughly 2000% (20 times) more light than the Velux.
Please note: Independent tests of efficiency figures, whilst meeting the highest testing criteria, do not constitute a recommendation or guarantee from the test authorities involved.
Decomposition of light rays in flexible sun tube systems
The same is true for all of the systems, whatever the size or configuration (bends etc.), efficiency is king. Take the 250-300mm category as an example; the CSTB in France tested the Solarspot D-25 and Solatube’s 160 DS and return figures of 55% and 35% respectively. Then factor in that the Solarspot averages a diameter of 260mm compared to the Solatube at 237mm and the D-25 will deliver roughly 70% more light. In fact this level of efficiency allows it to deliver the same light levels as the larger Solatube 290-DS.
At the other end of the scale if you compare the Solarspot D-65 (650mm diameter) with the larger Solatube M74 (740mm diameter) and the extra performance of the D-65 allows it to deliver around 10% more light.
Whilst this is important to consider when fitting single units it’s vital when working on larger projects with multiple units. Take an office situation with 80 Solatube 290-DS units specified; by switching to the Solarspot D-38 it would be possible to reduce the number of units by 40%, greatly reducing the cost in both materials and labour, just replacing like-for-like and getting a massive 70% more light for better year-round performance.
Please note: BRE testing covers the Solarspot D-38, Solatube 290 DS and Sunpipe 450. Testing of 250mm diameter units; Solarspot D-25 and Solatube 160 DS, carried out by CSTB in France. Other figures shown are from manufacturers own testing.