The Energy Saving Trust is calling for improvements in the installation of heat pumps following a field study that showed many underperformed.
The
Energy Saving Trust conducted a 12-month field trial of
air and ground source heat pumps. While the trial found that heat pumps can operate
efficiently when installed correctly, it discovered that many of the devices underperformed as a result of incorrect sizing of systems, complicated controls, a lack of education for household users, and the use of multiple installers.
Comprehensive field trial
The trial was the first phase of a comprehensive field study of heat pumps. During the past year, researchers studied heat pumps at 83 sites, with 54 of these being ground source and 29 being air source.
The trial began in early 2009 and monitored technical performance and customers’ experiences for a year.
During the trial, a variety of early heat pump installations failed due to poor
design or installation. But when installed properly, results show that a number of heat pumps performed well, achieving an overall system efficiency rating of three and above – meaning every unit of electricity put in has an output of three units of heat.
"This trial shows that when installed and operated correctly, heat pump
technologies will save significant amounts of
CO2 in the UK, when replacing oil or traditional electric heating," said Simon Green, head of Business Development for the Energy Saving Trust. "But there is no doubt that the results are more varied than were expected, with results showing both high and low performing heat pumps."
Researchers found that heat pump performance is highly dependent upon appropriate installation and integration with the
building’s existing heating system, in cooperation with appropriate control by the customer. The Energy Saving Trust calls for improvement of installation techniques so that heat pumps become quality and mainstream ways to reduce carbon.
Improving the technology
Sustain, an independent green consultant firm, urged companies not to dismiss heat pump technology, but to make sure it is used correctly.
The company said the pumps work well in highly insulated new buildings where there is a low temperature distribution system, such as under floor heating. If insulation levels are poor, controls are not explained to users, or conventional radiators are used, the heat pumps will struggle to provide the performance quoted by manufacturers, it said. The pumps make the most sense for people using oil or electricity, not gas, as their main heating fuel.
"We are always looking for up to date research and good quality data that will help our clients," said Kevin Boniface, senior associate at Sustain. "We welcome the results of the study but urge the Government not to delay the introduction of the Renewable Heat Incentive, which encourages a range of
renewable technologies and is an important instrument for change."
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