In recent years, heat pumps have emerged as a promising new form of technology with a relatively low environmental impact. Moreover, they have presented householders with an opportunity to reduce their heating bills. Heat pumps can heat a building by 'pumping' heat from either the ground or the air outside: an intriguing process which utilizes principles that are somewhat analogous to those employed in the domestic refrigerator. Armed with the practical information contained in these pages, homeowners will have the necessary knowledge to take advantage of this potentially low-carbon technology to heat their properties.Describes what a heat pump is, how it works, the different methods of pumping heat and the importance of an appropriate and well-planned installation. Examines the air, the ground and water as sources of heat and explains how to make an informed choice. Considers the all-important subject of distributing the heat through radiators or through an under-floor system. Covers hot water production and delivery to the taps. Outlines environmental and financial issues associated with heat pumps. Dispels some common misconceptions and presents a number of case studies. Essential reading for all those householders who are considering installing heat pumps in order to heat their homes in a more eco-friendly and efficient way. Aimed at those homeowners who wish to do some of the work themselves or who wish to shadow sub-contractors. A useful reference tool for architects, plumbers, heating engineers, builders and students. Superbly illustrated with 155 colour photographs and diagrams by Gavin D J Harper. John Cantor is a heat pump engineer, inspector and consultant and has written many articles on the subject. Gavin D J Harper is a member of the Institute of Engineering and Technology.