This study evaluates different fuel cell system configurations for residential applications from an economic standpoint. The evaluation is made using a Monte Carlo simulation for different building types, heating systems, and rate structures. Electric and thermal energy produced and used, energy from the grid, and gas consumption are evaluated using a frequency energy model. This frequency model is based on detailed energy consumption measurements. Sensitivity analysis shows that the parameters defining the potential residential market are building type, utility rates, and heating systems. These are not related to fuel cell system characteristics. In general, the systems offering the lower annual net payment are fuel cells with about , no battery, cogeneration system for space heating and domestic hot water heating.