In this final thesis, we described what heat pumps are, how they work, what categories they are divided into, and finally we inserted one heat pump into the real system. We started from the left-handed thermodynamic system, which is the basis on which the operation of all heat pumps is based. Then we listed the important parts essential for the operation of the heat pump: working medium, compressor, condenser, expansion valves and evaporator, and we carefully explained their individual purpose in the operation of the heat pump itself. We have divided the heat pumps according to the type of media from which they take thermal energy: air, water, soil and to which they transfer thermal energy: air and water. Then we listed the systems in which heat pumps are used and we explained how heat pumps are better and more efficient than other systems for heating and cooling media that are most often used for heating and cooling spaces where people stay. In the end, we chose one system in the family house, calculated the energy losses and the required power for heating and cooling the selected space, and chose the heat pump suitable for it.