The present payer deals with the improved performances and thermal comfort of individual forced hot water heating systems equipped with a gas fired wall boiler, for homes. The problems of such systems are due to the high power of the burner which causes cyclic running. Furthermore, the installation of a room thermostat is imposed by the French thermal regulations. Developed independently from the boiler, the thermostat does not fit its environ ment. The manual aquastat set point adjustment at the boiler can lead to a set point conflicting with that of the thermostat. Hence, the authors have developed a new room thermostat, based on a fuzzy logic function, which takes into account the system reactions. This thermostat assimilates the characteristics of the different parts of the system: boiler, heaters, building, climate, etc. The new thermostat was tested in simulation and good results were obtained. Then. it was validated experimentally. (C) 2001 Elsevier Science Ltd. All rights reserved.