This simulation study investigated the influence of operating parameters and module and system design on performance and cost of pervaporation modules. It was based on isopropanol dewatering measurements with silica membranes and different types of methods to calculate heat and mass transfer resistance. It was shown that conventional modules need up to 50% more membrane surface than a new isothermal module design (Pervap SMS(R) by Sulzer Chemtech). The performance was evaluated by comparing depletion, pressure drop and polarisation effects lowering the module efficiency. Assuming a best-guess cost structure for dewatering with inorganic membranes, it was concluded that the optimum lies in the range of high cross-flow velocities/Reynolds numbers. Pressure drop values around 10 bar may still be economical, but module arrangement plays a smaller role due to a near constant mass flow on the feed side.