Open Loop Ground Source Heat Pumps (space heating)
A heat pump works by extracting heat from the environment and transferring that heat to your home. They need some electricity to run, but because their heat output is higher than the electricity input, they are highly efficient, low carbon heating systems
This page details the criteria used to select open loop ground source heat pumps for toptenuk.org. The heat pumps displayed here are all able to supply heat for space heating or space heating and domestic hot water. Air-based distribution systems are not included in this list – only wet heating systems. Heat pumps which only supply domestic hot water only are covered in a separate category on the topten website, Domestic Hot Water Heat Pumps.
For space heating and domestic hot water heat pumps, only those that reach the minimum criteria specified below are displayed on the website. For more details on how they operate and things to look out for when purchasing one, please see our Product Guide.
Open loop ground source heat pumps
In these heat pumps the heat is collected from ground water (aquifer) or surface water by circulating the water through a direct, open-loop heat exchanger. These are also called ‘Water-to-Water’ heat pumps, especially in regulations.
The minimum criteria to be shown on toptenuk.org is shown in Table 1 which covers certification and energy performance metrics.
Table 1: Current selection criteria for open loop ground source heat pumps.
MCS certified or equivalent
Must carry the EHPA quality seal
Must be serial product (i.e. no prototypes/one-off systems)
*SCOPs calculated using average climate conditions and design criteria defined by Commission Regulation (EU) No. 813/2013.
The following regulations were the basis for the above selection criteria for heat pumps.
MCS certified or equivalent - To qualify for the top ten website, heat pumps must be MCS certified or equivalent. In order to receive this certification, the heat pump must meet the standards set by MCS. Details of the standards are given here on the MCS website.
Coefficient of Performance – Ratio of heat energy produced to input electrical energy. For example, if a heat pump produces 4 kWh of usable heat for a home and requires 1 kWh of electricity to do so, it has a COP of 4.
Seasonal Coefficient of Performance – this is an average coefficient of performance taken across the entire heating system.
Standard BS EN 14825:2018 Air conditioners, liquid chilling packages and heat pumps, with electrically driven compressors, for space heating and cooling. Testing and rating at part load conditions and calculation of seasonal performance; https://shop.bsigroup.com/ProductDetail?pid=000000...