The combustion of methane on a surface burner is investigated numerically for both an active and a catalytically inactive surface. Results are compared with experiments performed on a small-scale model of a production household burner. A global approach is used to model surface processes, whereas gas-phase chemistry is described in terms of a detailed reaction mechanism. The simulation shows the importance of radical desorption from the surface. In order to reveal further NOx reduction potentials, a NOx formation analysis indicated the mechanisms important in surface burner systems. The results reveal the importance of NNH reactions for NOx formation.