A reputable company who offers solar pv installations should be completely transparent about the warranties and guarantees that are put in place. These warranties and guarantees are put in place by both the installers of the solar pv equipment and also by the manufacturers of the solar pv equipment that the installers would then install upon the property.
The first aspect of the guarantees and warranties package is the workmanship warranty. This is given from the installer and ensures that any labour needed to rectify any problems that may have been caused by the installer will not be charged to the customer. This warranty is dependent upon the installer but typically a solar pv company will back up their work with a 10 year workmanship warranty.
The next aspect of the guarantees and warranties package is the manufacturer’s guarantee. Like with most products offering such a guarantee, this is put in place by the manufacturer themselves rather than by the installers and covers any physical malfunctions or degradation of the equipment. Often the panels used and the inverter used on a solar pv system will have been manufactured by different companies. This would therefore mean 2 separate guarantees. Manufactures guarantees are typically valid for 10 years.
The final piece of the jigsaw is the guarantee put in place to cover the performance of the panels. This is crucial in ensuring that the system gives you the return on investment that you were promised it would. This means that even if the panels are in a physically sound condition, they would be replaced if they fall below a certain level of performance. Like most technology, a slight drop off in performance is inevitable, however most tier 1 solar companies now offer a 25 year linear performance guarantee that ensures the drop off in performance will not exceed 0.7% in any given year.