The design and the operational characteristics of a new isoperibolic calorimeter that is developed to study the electrochemical insertion of deuterium into palladium are described. The design is simple and involves inexpensive materials to build. It possesses a number of distinct advantages that makes it suitable for thermal measurements in other electrochemical systems. It is insensitive to the nature and the location of the heat source within the electrochemical cell. The calibration constant is found to be stable with ±0.5% uncertainty over a wide range of input power levels up to 22 W. It also has the capability of operating over a wide temperature range. In principle, the calorimeter can be used up to 600°C, provided that the electrochemical cell design and materials are chosen appropriately. The design also provides flexibility to adjust the sensitivity of the calorimeter according to the needs of the system under study.