Abstract: A catalytic calorimeter measures the heat value of a gas and includes a chamber for receiving gas and air. A catalyst within the chamber causes the combustion of the gas and air, while a first thermocouple provides a signal indicating the temperature of the gas and air prior to combustion. A second thermocouple indicates the temperature of the catalyst, which is heated by an electrical resistance heater. A first temperature controller is connected to the second thermocouple and the heater for maintaining the catalyst at a predetermined temperature. A heat sink within the chamber absorbs heat from the products of the combustion of the gas and a third thermocouple indicates the temperature of the heat sink. A Peltier effect thermoelectric cooler is provided to remove heat from the heat sink. A second temperature controller connected to the third thermocouple and the cooler maintains the heat sink at a predetermined temperature.