Rooftop photovoltaic (PV) systems can be readily deployed on industrial halls with relatively large rooftop area. Feed-in tariff above the base price of electricity is offered in many countries to subsidize the high initial investment of PV systems. In order to fully capitalize the benefit of the feed-in tariff, the investigation of the actual performance of PV systems under case-specific conditions is very important. With building energy simulation, this paper explores the cost-benefit of implementing PV systems of different capacities for a few different cases of industrial halls. The impact of various economic parameters is also investigated.