When thinking about installing a solar power system, it is important to carefully consider the types and durations of the warranties offered by solar system installers. Like most technology products that you buy, solar panels come with warranties that help safeguard your investment in the unlikely event that a problem occurs after installation.

When evaluating solar panel manufacturers, the two most important warranties on which you should focus are:

  1. Product/materials/workmanship warranty, and
  2. Performance warranty.

Product/materials/workmanship warranty

  • A workmanship warranty, sometimes called a materials or product warranty, is usually valid for anywhere from 1 to 10 years, and will cover the components that make up your system’s panels: the glass, laminate, backing, and possibly the silicon cells/wafers contained within.
  • Damage to these parts of the panel, although unlikely, may result in major or minor losses to their electricity production capacity. These warranties exist just in case something untoward happen to your panels.
  • Some important things to consider and questions to ask:
    • Is the materials warranty from the panel manufacturer or your system installer? If it is the manufacturer, make sure you know if you will have to send your panels overseas to have them serviced. Will you have to pay to have them shipped?
    • Are there any contractual requirements for regular maintenance of the panels, which if not undertaken could void your warranty? If so, what are they and how much will they cost?
    • Who is the manufacturer/installer? How long have they been in business? Are they reputable?

Performance warranty

  • Generally, the silicon (encased in glass in your solar panels) will be the most durable, long-lived part of any panels –provided there are no incidents that damage them. For this reason, performance warranties ordinarily last between 25 and 35 years.
  • Performance output warranties will cover repairs for the silicon cells themselves, should their electricity production fall below a predetermined percentage of the panels’ rated capacity.
  • For instance, you would be covered in the case that your array output falls below 80% and the drop is due to a defect in the cells themselves (not due to a fault of the rest of the system, known as Balance of System or BoS).
  • Some output warranties may also be graduated, e.g. 90% of rated performance efficiency at year 15, 80% performance efficiency at year 35, etc. The fact is, though, that panels may continue to produce electricity even after the warranty has expired, possibly at a rate very close to the system’s nominal capacity.
  • Some important things to consider and questions to ask:
    • Is your output problem really an issue with your panels’ productivity, and not the BoS? How is panel performance measured?
    • Is the performance warranty through the manufacturer or through your installer? Will you have to send your panels overseas to have them serviced if something goes awry?

Other solar power related warranties

  • Inverter warranties: A warranty for your inverter is absolutely critical. Inverter warranties typically last for 5 to 10 years, although your installer may also offer extended warranties on request. Make sure that you have selected the right inverter for your system size, check the reputability of the manufacturer and the model; installing a wrongly-sized inverter could void the inverter warranty.
  • Battery warranties: If you have a stand-alone system or a hybrid system, it will include batteries, which typically have warranties of 5-10 years. Batteries are the most maintenance-intensive and expensive parts of a stand-alone power system. Be sure that you understand the maintenance requirements to ensure that you are in compliance with your battery bank’s warranty conditions.
  • Balance of system warranties: Your installer may also warranty for the balance-of-system (non-panel components of your system) in order to cover miscellaneous issues with your system, such as wiring, junction box, mounting systems, etc. Ask the installer about what is on offer.

Conclusion

Suffice it to say that higher 25-year performance warranties (i.e., slower degradation) are viewed more favourably than lower performance warranties, but as a practical matter the performance warranty may be a better indicator of a panel’s intended degradation behaviour than of its manufacturer’s support practices. Be attentive and take time to read through the documentations regarding the warranties to get a clear picture of what the manufacturers offer for your products.

Manufacturers offer warranties of varying lengths. On average these consist of:

  • 10-year limited product warranty (materials and labour)
  • 25-year limited power warranty (typically 10 years at 90% power output and 25 years at 80% power output)
  • Workmanship and materials warranty of one or two years
  • Batteries (non-grid systems / hybrids) roughly 5-10 years

Inverter(s) warranty of between 5-10 years

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