The meter forms part of a heating system supplied with thermal energy in the form of hot water from a heat generator, and serves to determine the amount of heat supplied to a consumer, for the purpose of appropriately charging the consumer for incurred heating costs. The meter includes a computer, operating on the analog principle, a volumeter and connection elements for connection to signal processing devices. The volumeter is formed by a first tubular body through which the hot water flows to the consumer, and this first tubular body is surrounded coaxially, at a definite radial spacing therefrom, by a second tubular body so that the two tubular bodies define a completely closed annular space. The cooled hot water returns through a return line. The supplied hot water in the first tubular body constitutes a primary medium flowing therethrough, and the completely closed annular space receives a secondary medium which is heated by the primary medium. A temperature sensor and a pressure head probe are operatively connected to the first tubular body, a second temperature sensor is operatively connected to the return line, and electronic elements convert the pressure head into an electrical quantity proportional to the volume of the primary medium flowing through the first tubular body. The temperature sensors serve to determine the heat amount. A thermogenerator is connected in communication with the completely closed annular space, for generation of electric energy by the heat of the secondary medium, and an electronic transformer is connected to the thermogenerator to convert the generated electric energy into operating potentials applied to the computer and to the volumeter.