Gas sensors are used in many different application areas. As many gas sensor components are battery heated, one major limit of the operation time is the power dissipated as heat. The aim of this work has been to simulate the heat transfer on a hydrogen gas sensor component. Modelling and simulations have been performed in FEMLAB. The partial differential equation with boundary conditions was solved and the solution was validated against experimental data. Convection increases with the increase of hydrogen concentration. A great effort was made to find a model for the convection. When the simulations were compared to experiments, it turned out that the theoretical convection model was insufficient to describe this small system involving hydrogen, which was an unexpected but interesting result.