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New data analysis provides evidence on in-situ heat pump performance

Posted: 23 May, 2024. Written by Virginia Graham

Comprehensive evidence to be published by RECC and the Ground Source Heat Pump Association (GSHPA) shortly provides new insights into the system performance of 1,700 air and ground source heat pumps (ASHPs and GSHPs). These heat pumps were subject to strict monitoring by Ofgem under the Renewable Heat Incentive regulations. The independent research funded by the GSHPA, RECC and the Department for Energy Security and Net Zero (DESNZ) provides:

•   median and mean Seasonal Performance Factors (SPFs);

•   SPFs for installations carried out in specific years from 2017 to 2022; and

•   results broken down by GB country and English region.

The report builds on a similar exercise carried out in 2019 using a previous dataset provided by Ofgem. At that time, a methodology was developed to process the data and calculate the in-situ system efficiencies. The new research, with a much larger dataset, compares the in-situ efficiencies calculated versus the ‘as designed’ performance using the installer-provided Seasonal Coefficient of Performance (SCOP) forecasts included in the dataset. The results are also compared with the Renewable Heat Premium Payment (RHPP) field trial published in 2017 and the 2024 results from the Electrification of Heat Demonstration Project (expected to be published in June 2024).

The results provide good evidence of heat pumps performing well. For example, the average GSHP SPF has improved significantly from just over 3.0 in 2017 to 3.31 in 2022. 67% of all GSHPs and nearly 30% of all ASHPs performed at SPF 3.0 or above. Exactly one third of GSHPs and 8% of ASHPs were performing at SPF 3.5 or above.

However, those and other positive results are tempered by findings showing that ASHP performance has not improved since 2017; and that a disappointing proportion of installations - ASHPs in particular - are performing with low or very low SPFs. A significant performance gap between the design SCOPs and the in-situ efficiencies remains for both ASHPs and GSHPs. This research shows that average design SCOPs have jumped. For the ASHPs installed in 2022, the gap between the mean design SCOP and the mean SPF has grown to 1.04.

Overall, consumption and generation data from 1,400 ASHP and nearly 300 GSHP installations subject to ‘Metering for Payment’ rules was analysed. The research was carried out by rb&m ( in March and April 2024. You can read the full report below:   

Further Information: