This paper introduces an analytical modeling of a convective CMOS accelerometer. The device is a one-axis accelerometer based on a three bridges structure (one heater and two detectors). The modeling relies on the use of heat transfer fundamentals and is validated using experimental data issued from both test-vehicles and FEM analysis. It describes the heat conduction phenomenon that determines the thermal initial condition and then the convection mechanism that provides the sensitivity to the acceleration. Although only the static model is detailed, the dynamic behavior of test samples has been characterized and included into the HDL module. In order to illustrate the use of the model, the sensor is simulated together with its control electronics in an implementation of an A/D modulator. Simulation results are then compared with physical measurement with good agreement.