When discussing the warranty of a solar system it is broken into a few different types.
Workmanship warranty (This covers the installation) Ranges from 10yrs to 25yrs
Panel Warranty (This is dependent on the manufacture of the panels, most are 25yr warranties.)
Production/ Performance Warranty (This will vary upon the manufacture of the solar panels. Some offer up to a 30yr performance warranty.)
Inverter Warranty (Most inverters offer a warranty of 10yrs to 25yrs. There are options to buy an extended warranty if needed. )