The heat pump monitoring datasets are a key output of the Electrification of Heat Demonstration (EoH) project, a government-funded heat pump trial assessing the feasibility of heat pumps across the UK’s diverse housing stock. These datasets are provided in both cleansed and raw form and allow analysis of the initial performance of the heat pumps installed in the trial. From the datasets, insights such as heat pump seasonal performance factor (a measure of the heat pump's efficiency), heat pump performance during the coldest day of the year, and half-hourly performance to inform peak demand can be gleaned. For the second edition (December 2024), the data were updated to include cleaned performance data collected between November 2020 and September 2023. The only documentation currently available with the study is the Excel data dictionary. Reports and other contextual information can be found on the Energy Systems Catapult website. The EoH project was funded by the Department of Business, Energy and Industrial Strategy. From 2023, it is covered by the new Department for Energy Security and Net Zero. Data availability This study comprises the open-access cleansed data from the EoH project and a summary dataset, available in four zipped files (see the 'Access Data' tab). Users must download all four zip files to obtain the full set of cleansed data and accompanying documentation. When unzipped, the full cleansed data comprises 742 CSV files. Most of the individual CSV files are too large to open in Excel. Users should ensure they have sufficient computing facilities to analyse the data. The UKDS also holds an accompanying study, SN 9049 Electrification of Heat Demonstration Project: Heat Pump Performance Raw Data, 2020-2023, which is available only to registered UKDS users. This contains the raw data from the EoH project. Since the data are very large, only the summary dataset is available to download; an order must be placed for FTP delivery of the remaining raw data. Other studies in the set include SN 9209, which comprises 30-minute interval heat pump performance data, and SN 9210, which includes daily heat pump performance data.  The Python code used to cleanse the raw data and then perform the analysis is accessible via the Energy Systems Catapult Github Heat Pump Performance across the BEIS funded heat pump trial, The Electrification of Heat (EoH) Demonstration Project.  See the documentation for data contents.