Numerical modeling of Si homoepitaxial deposition from in the horizontal reactor has been undertaken employing the steady‐state, fully parabolic flow approximation for the heat, momentum, and mass‐transfer equations. Reactants are assumed to be dilute in their carrier gas. The resulting set of partial differential equations are discretized using finite elements and solved using the method of lines. The effect of a third dimension, the side temperature boundary conditions, and natural convection are explored. Given recent kinetics data on the silane decomposition and silylene insertion reactions, it is shown that a quasi‐thermodynamic equilibrium exists in the heated region above the surface, at least for hydrogen gas ambients. The combination of a fast silylene surface reaction and a slow silane surface reaction implies that the effective surface reaction rate is governed by the homogeneous thermodynamic equilibrium in the gas phase and diffusion through a thin mass‐transfer boundary layer near the surface. Examples of how tilting the susceptor contributes to growth uniformity are presented, and the effectiveness of similarity solution models at predicting this enhanced axial uniformity is tested.