Researchers from the Open University carried out a field trial into user experiences of domestic heatpumps, in partnership with the Energy Saving Trust. 83 households were involved in the field trial (2009-2010) which involved an in-depth user survey and monitoring of their heat pump use. Both private householders and social housing residents were included. The surveys found that most users were satisfied with the reliability, heating, hot water, warmth and comfort provided by their system. Analysis of user characteristics showed that higher system efficiencies were associated with greater user understanding of their heat pump system, and more continuous heat pump operation. The analysis also found that the most efficient systems in the sample tended to be located in private dwellings rather than at the social housing sites. This was related to the larger size of the private dwellings, and the fact that heat pump installations were often part of newly built systems rather than installed as retrofits.