Recent research has allowed improved modeling of residential photovoltaic systems currently being deployed throughout the United States. In particular, aware of how photovoltaic systems perform under various environmental scenarios has improved giving those who buy or lease residential systems better insight into the economic performance of their systems and ultimately their investment. One aspect that affects performance is the impact of soiling. In this paper an empirically derived soiling model is assessed against other soiling assumptions on financial payback. In addition, potential owners are required to make decisions that will determine how quickly their investments will pay for themselves. These factors include cost of financing and tariff characteristics. Also, utility incentives have a significant impact on the return of a PV investment. Results show that potential buyers of photovoltaic systems need to examine certain economic assumptions to accurately assess whether or not to pursue an investment in a PV system.