These days, warranty periods are similar across most products, what is more important is how usable the warranty is in the case of a claim.
Your inverter should come with a minimum of a five-year warranty, with quality suppliers offering extensions to 10 years free of charge or with minimal additional cost.
Solar panels or modules come with two types of warranties. The first is a performance warranty, which is a minimum guaranteed output from the panels, generally over a 25 year period. The second is a warranty on the manufacture of the module itself, which is for 10-12 years, covering items such as the glazing, framing and wiring.
Also very important is the workmanship or installation warranty – Solargain offers a five-year installation warranty.