Are you confused about the wording on some solar panel guarantees and/or warranties? Well, you're not alone, but first let's define what is a guarantee and what is a warranty.
Guarantee: A formal promise or assurance (typically in writing) that certain conditions will be fulfilled, especially that a product will be repaired or replaced if not of a specified quality and durability.
Warranty: A written guarantee, issued to the purchaser of an article by its manufacturer, promising to repair or replace it if necessary within a specified period of time.
So a guarantee looks to be more like a loose promise, whereas a warranty is in written form and contains a guarantee with certain time limits. In this discussion we'll assume we're working with written warranties, whether packaged in with the product, or more likely these days, posted somewhere on a manufacturers' web site.
Residential and commercial solar panels come with warranties that are very different to those accompanying marine solar panels. These aluminum-framed glass panels are fabricated by automated processes in huge numbers where quality can be closely controlled and monitored, and so their construction is normally warranted for two years.
But there is also a warranty on the power output, where typically 80% of the rated output is guaranteed after 20 years or so in operation. This is feasible to implement due to the fact that the utility company or solar provider constantly monitors the output from day one, and so an ongoing record is available.
The power output of silicon solar cells naturally degrades slightly over time, and so this slow loss of performance is quite predictable.
So what happens if the power output of the panels on your roof of your house has degraded beyond the warranty limits after the 20 or 25 years or whatever? Will the solar company come and replace your 20+ year old panels free of charge? Well no, but they will offer to ship one or two panels, for you to install, to make up the difference!
Unlike residential and commercial solar panels, the long-term power output of marine versions is not normally guaranteed, as this aspect of performance is absolutely impossible to monitor in practice.
One wonders what the response from a marine panel manufacturer might be if you were to contact them 20 years after installing their panels (if indeed they were still in business) to say that somehow you just know, you just have this strong gut feeling, that the panels are putting out less than 80% of what they did 20 years ago!
Imagine the dilemma that marine solar panel manufacturers are faced with when compiling warranties.
Marine panels are not permanently fixed and held stationary on a stable platform from day one like residential and commercial panels. A house does not up-anchor and set sail to exotic places subjecting the solar panels to all sorts of abuse along the way like vibration, kinetic and torsional loads, exposure to a salt water environment, and regular bouts of rough and tumble.
Because marine solar panel manufacturers have no control over how their panels are installed and operated in the field (bay, ocean, etc.), worthwhile warranties are restricted to the actual construction of the panels. As with all warranties, marine solar warranties are only as good as the company that issues them.
Solbian, in Italy, and Solara, in Germany, are the two marine solar panel manufacturers that Coastal Climate Control works closely with, and both are well respected companies that truly stand behind their warranties. Both Solara and Solbian offer full 5 year warranties on the construction of their marine solar panels.
So the next time someone at a boat show asks if we give a 20 year warranty on our marine solar panels we will respond; "No, we absolutely guarantee it"!