Warranties for solar electricity panels and systems are confusing and it is understandable why a consumer would assume that they all must be the same. However this is not the case and the following article will give you an insight into the kind of differences you should be aware of.
Parts, Materials and Labour Warranties
Solar PV component parts and material warranties are very similar to warranties that we all deal with every day. Parts and materials warranties cover the owner against defective parts or materials for a determined length of time. These warranties vary from 2 years up to about 20 years. This is an indication of the manufacturers confidence that the panels will not fail and assuming it is a reputable manufacturer can be an indication as to the quality of the product.
REC PV Modules carry a 12 year product warranty
Hisunage Modules carry a 20 year product warranty
Intelligent Energy Solutions typically offer a 5 year labour warranty
Zeversolar inverters carry a 10 year warranty
Sola X inverters carry a 20 year warranty
Module Performance Warranty
PV Modules are commonly defined by their peak power. This is the rate at which a PV module will generate electricity when the sun is shining brightly (1000W/m2). This peak power will degrade over a period of time and the performance warranty gives the customer assurance that it will not degrade faster than a specified rate.
It is not unusual for a module to output only 80% of its original specification after 25 years. This affects the overall revenue generated from the PV system over its lifetime.
Additionally you should be aware of the power output that the manufacturer will consider to be within specification on day 1. Most manufacturers quote a peak power with a positive and negative tolerance. For instance if a module is 100W +-3%. This means that the module will be fully within its manufacturing specification if it outputs 97W, this is disappointing for the consumer when you ‘thought’ you were purchasing a system made up of 100W modules (not 97W modules). In summary, a typical module with an 80%, 25 year performance warranty will be within specification if it is outputting just over 77Watts (80% of 97 Watts) after 25 years.
Furthermore, what would you expect the supplier to do in the event that the module does fall out of specification? Many people expect the manufacturer to replace the module. This is not usually the case, many manufacturers have inserted small print into the warranty terms that give them the option of simply reimbursing you financially. This wouldn’t be so bad if the reimbursement was based on lost FiT payments, but it isn’t. Most manufacturers will reimburse you for the original cost of the panel minus a 5% year on year depreciation. This means 20 years later, the end user is reimbursed only a tiny fraction of the lost revenue and still has the defective panel on their roof!
The performance warranty is not the same as the parts and materials warranty which is usually significantly shorter. If a module with a 25 year performance warranty fails in year 15 and it is not associated to the degradation of the solar cells then this fault is not covered by the performance warranty. Such a fault is a part or material fault and you should refer to the parts and materials warranty.
We would recommend that look for quality cells, sun-soaked cells (see ‘how does it work’ section) that have a positive manufacturing tolerance, at least 80% performance warranty after 25 years.
Module Performance Warranty 
