This is a difficult question to answer precisely, because the cost depends on a few different factors. Broadly speaking, it costs about $16,650 for a 5-kW system and $33,300 for a 10-kW system after the ITC is applied. It will be more expensive if you want extra solar equipment or higher quality panels, or if you have higher-than-average energy consumption. On the flip side, you can spend less if you opt for a smaller solar panel system or less efficient solar panels.