The thesis describes in detail the cogeneration of heat and electricity, with a focus on its practical use. It observes the basic physical characteristics and compares general technical characteristics of individual CHP technologies. The situation in the field of CHP in the European Union and Slovenia is assessed along with some general energy indicators. It also describes the process of obtaining permits for a production unit along with a brief review of the technical conditions with which the production unit must comply when connecting to the electricity network. Some possible ways of financing the purchase of CHP units are presented as well as possible options for financial support of the operation. The last part of the thesis is devoted to examples of good practice in installations of CHP production units, together with a practical demonstration of a reconstruction of the heating system of a residential building with a CHP unit, and a hypothetical presentation of the impact that the rehabilitation of heating systems in households with installation of CHP units would have on the power supply.