UK: Technical data obtained from an in-depth study of heat pumps at sites across the UK has confirmed that well-installed and operated heat pumps perform to a very high standard in domestic homes.

The new field trials study from the Energy Saving Trust builds on the phase 1 study it published in 2010 which found widely varying efficiencies across the 83 installations surveyed. These varied from COPs as low as 1.2 to as high as 3.3. The best-performing systems were those that were deemed to be properly designed and installed.

The latest study covering 44 heat pump sites, were conducted between 2010 and 2013. The variations in performance were investigated with interventions carried out to achieve improved performance from the heat pump installations. Overall 20 of the 32 heat pumps undergoing interventions between Phase 1 and this study achieved improvements in performance with the remainder achieving similar or slightly lower performance.

The majority of sites taken forward from Phase 1 were those that showed the worst measured performance. In several cases, the manufacturers, having inspected their own sites, felt that the heat pumps were incorrectly sized for the property. To rectify this, a number of heat pumps were replaced as part of Phase 2 implementing the installation standards at the time. These were classed as major interventions.

According to the Energy Saving Trust, homes best suited for heat pump installations could expect to earn savings and income of around £1,350 a year on air source heat pumps and around £3,000 a year on ground source heat pumps (figures based on a four bedroom detached property with 250mm loft insulation and filled cavity walls with electric storage heating and using the recently announced RHI tariffs).

The success of the heat pumps’ performance during the study was underpinned by the experience of the users. Eighty per cent were said to be satisfied with their heat pump’s performance, while over three quarters (77%) would recommend a heat pump to a friend, mainly because of its efficiency and running costs of the system.

“Based upon the results of the study, we are convinced that heat pumps can play a significant role in providing an effective heating solution for homes and reducing carbon emissions,” said Jaryn Bradford, the Energy Saving Trust’s senior technical manager.

“From the study, it is clear that heat pumps are sensitive to design, commissioning and how the householder uses the system. However, the performance monitoring trials have provided early indications that the introduction of improved installation standards, amongst other things, will lead to improved performance,” he added.

“The interventions carried out during the study are an early indication of the successes that robust standards can achieve. If heat pumps were installed today under the current installer guidelines, alongside further customer guidance on operating the system, they would achieve even better performances than indicated in the study.”

The latest heat pump study was supported by funding from DECC, the Energy Technologies Institute, EDF Energy, Npower, British Gas, Scottish Power, Scottish and Southern Energy (SSE), E On UK, NIE Energy, Danfoss UK, NIBE and Mitsubishi Electric.

The full report can be downloaded here

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