Study Reveals Solar Water Heating Benefits and Savings

In what to date is the largest field trial of its kind to be undertaken – taking in some 88 domestic installations – the installation of a solar water heating system is capable of meeting more than half of a households’ hot water needs, in addition to saving most owners £55 a year.

With average solar thermal systems costing between £3,000 to £5,000, add to the mix poor monetary annual savings and the news won’t be warmly welcomed. But it just goes to highlight the need for clarification over the Government subsidies that have been designed to support and encourage the uptake of the renewable heating technology.

Under the Renewable Heat Incentive, the Government will provide financial support to homeowners who install renewable heating technology. However, the residential tariff levels that are going to be available are not due to be announced until next year.

The Energy Saving Trust has conducted similar field trials, and it’s worth noting that studies monitoring the performance of heat pumps and micro wind turbines have failed to live up to performance expectations. Solar thermal, however, performed better, with the systems deemed to work well in the UK. So much so, the Trust said the field study results were impressive.

Solar water heating systems were revealed to provide a median of 39% of a households’ hot water needs. At its best, the system managed to achieve 60%, although the figure plummeted to just 9% for the worst-installed system. Based on laboratory tests, it had been estimated that they would achieve a typical figure of 35-40%.

The results also revealed that the pumps that powered the systems used between 1 and 23% of the energy generated, which would achieve a cost of just £8 in electricity for a typical system annually, unless the pumps were powered by free electricity achieved from  a similar solar PV installation.

“This is a technology that works, and works well in the UK,” said Jaryn Bradford, senior technical manager for the Energy Saving Trust, who compiled the report.

He added the biggest impact on the performance of a solar water heating system was down to how well insulated the hot water tank and pipes were.

Presently, 140,000 homes in the UK are estimated to have installed a solar thermal system.