Viridian Solar Measures up the Benefits

Results from the most rigorous UK test of any solar water heating system have been announced. When asked about the energy savings from their products, many solar water heating suppliers offer vague answers, and with good reason - as Viridian Solar has recently found out. Proving the benefits scientifically is time consuming, difficult and expensive.

However, in launching its roof integrated solar panel - the Clearline, Viridian Solar set out to do just this: ‘We felt that it was important to be able to offer realistic information to our customers, not best case scenarios and arm-waving,’ explains Stuart Elmes, Chief Executive of Viridian Solar.

‘The standard industry response is to claim that solar water heating can provide 'up to 70%' of your hot water energy’, he continues, ‘best case information like this is of course meaningless if not put in context. How many actually achieve 70%? Is it one percent, or ninety percent of households? What does everyone else get? Is it 69% energy savings or 10% savings?’

Viridian worked with housing association partners Places for People and Hastoe Housing to choose the six houses for the study. Measuring equipment was selected by the Building Research Establishment (BRE), which also downloaded the data and produced an independent report at the end of the twelve month period.

Unlike previous monitoring studies, the householders did not invest a large sum of their own savings to install the systems. As such, they could be considered to be much more representative of how mainstream households might interact with the technology once it becomes more widely deployed.

Key findings from the study:
* Annual energy savings were in the range of 1,500kWh to 850 kWh, with an average of 1,200 kWh. This corresponds to an average carbon dioxide saving of 230kg/year (natural gas) to 500kg/year (electric heating).

* The way the household runs their heating system can have a big effect on the savings they achieve.

* The solar savings varied from 70% of hot water energy in the most optimising household, down to 26% in a household that ran their gas boiler 24/7.

* User interfaces on electronic timer controllers for the household heating system were too complex for many householders. Heating systems were either run manually, or left on all the time, negating the supposed energy benefit from fitting the controller.

Using insights from the study, Viridian Solar has produced a simple Solar User Guide that coaches householders in getting the best savings out of their solar heating system.

The full text of the report can be downloaded from:
http://www.viridiansolar.co.uk/Solar_Monitoring_study.htm