Different types of warranties are available for solar panels.
But the main warranty that you should definitely not miss out on is the Performance Warranty, which specifies the efficiency that the solar panel will have over its lifetime.
Good quality p-Si panels will also come with 25 years warranty. Thin films, as they degrade faster, come with a shorter warranty.
Within this warranty, for crystalline solar panels, you can either have a Standard Warranty, or a Linear Warranty. A standard warranty is not as optimal as a Linear Warranty as solar panels sporting the the latter are likely to result in higher generation overall, to the tune of about 5%.
The Linear Warranty could cost a bit more than the Standard Warranty but the results more than compensate for the higher cost.
Let me illustrate better.
Manufacturers will usually guarantee a minimum performance for crystalline silicon panels as follows: 90% of the rated output for around first half of 25 years, and 80% of the rated output for the remaining of the 25 years.
Better that this guarantee, some panel manufacturer provide a linear performance guarantee. Under linear performance guarantee, usually a maximum degradation of 2.5% is guaranteed in the first year, and some value in the range of 0.5–0.7%/y thereafter.
Over 25 years of operation, a linear performance guarantee can increase cumulative generation of power by more than 5%, at the cost of a slight increase in the price of panels.
You Might Want to Check Out these Questions Too on Performance
- Will a Solar Panel Really Last 25 Years?-Here
- How Much Electricity Will Solar Panels Produce in a High Sunlight Region?-Here
- How Much Electricity Will Solar Panels Produce in a Moderate Sunlight Region?-Here
- How Much Electricity Will Solar Panels Produce in a Low Sunlight Region?-Here
- Do Some Solar Panels Perform Better than Other in Low Sunlight?-Here
- How Do I Know if My Solar Panels are Generating Maximum Possible Electricity?-Here
- How Do I Know Thin Film Solar Panels Can Work for 25 Years?-Here
- Is Choosing a Very High Efficiency Panel a Good Idea?-Here
- How Can I Maximise Generation from Solar Panels from a Limited Rooftop Area?-Here
- What is the Highest Efficiency for Solar Panels in 2016?-Here
- Do High Efficiency Solar Panels Generate More Electricity than Low Efficiency Panels?-Here
- What Will be a Solar Panel’s Efficiency After 25 Years?-Here
- What are the Typical Solar Panel Efficiency I Should Look for?-Here
- How Much Generation Decrease Can Result from Dust on Solar Panels?-Here
- How Much Electricity will a Solar Panel Generate in a Year?-Here
- How Does a Standard Performance Guarantee Work for Solar Panels?-Here
- How Does a Linear Performance Guarantee Works for Solar Panels?-Here