Abstract: A central heating system includes a boiler and uses a burner to heat a heat carrying medium, which is in the form of a liquid. The system includes also one or more chargeable electric batteries, an electric generator for charging these batteries, a steam engine for operating the generator, and a steam generator for powering the steam engine. The steam generator receives its heat, for the steam generation, from the flame of the burner and delivers this steam to the steam engine, thereby operating the electric generator. This electric generator is dimensioned to give the batteries a total amount of charging energy which exceeds the total amount of energy that is required by the electric current consumpting apparatus.