In this work, a novel sensor for measuring the viscosity of a gas, based on the combination of a heating cavity, a pressure sensor and a meander with a high resistance to flow, all integrated in low-temperature co-fired ceramic (LTCC) technology, is presented. This paper reports the design, thermal characterisation and modelling of the heater module in quasi-stationary operation. The performance of the heater is satisfactory, and good agreement between experimental and calculated thermal properties is found. Nonetheless, some design changes are recommended, in order to improve heat transport in the heater module.