The aim of this paper is to present heat pumps as energy and environmentally sound solution in heating systems that are used for residential purposes. The basic principle the operation of the heat pump relies on is presented as well as thermal sources and the most commonly types of heat pumps used for such purposes. The simulation of an air-water heat pump used for water preparation and heating is given for three basic cases: high, average and low energy efficient facility. The analyses how energy efficiency takes a part in energy, ecological and economic parameters is showed as well.