Warranties are a big deal. Especially in solar. Solar systems are expected to operate in all weather conditions for decades. So what are the important points of module (panel) warranties? What are the parameters and conditions that matter, and how does a power warranty work? We’ll take a look.

What’s the point?

Previously we covered solar manufacturer warranties here and solar labor warranties here. In this post, we’ve spent the time to digest the warranty documentation for 4 different module manufacturers, so readers can get an actual feel of how module warranties are structured, what the relevant parameters are, and see how 4 leading companies stack up against one another.

A lot is made of warranties, and for good reason: people want peace-of-mind. That said, there are several items that we explore in this post. We’ll take a look at the following relative to the comparison table provided later in the post.

  1. Special parameters and requirements and processes for making warranty claims.
  2. How power warranties work

Lets begin…

 

 

Special Parameters & Requirements

Here are some of note:

  • Proof of Purchase – most companies require some form of proof of purchase. So its important that the appropriate documentation is provided.
  • Transferability – generally manufacturers allow for the transfer of product warranty to another ownership entity. Some require notification.
  • Term Start Date – some manufacturers start the clock when the product is installed. Others start when a distributer receives the product.
  • Claim Process – all allow for product owners to directly contact for claims. Some allow for authorized reps or the installer to initiate claims.
  • Labor Warranty – some manufacturers have a labor warranty in place – if the product fails, the manufacturer helps pay for repair labor.
  • Product Location – all manufacturers require that the product is in its original installation location for a claim to be entertained.
  • Workmanship Warranty Threshold – each manufacturer has one, but they are rarely fully described.

Warranty Comparison Table

Brand SunPower Panasonic LG Canadian Solar
Power Warranty Term 25 Years 25 Years 25 Years 25 Years
Workmanship Warranty Term 25 Years 25 Years* 25 Years 10 Years
Term Start Date The earlier of either the Interconnection Date OR 6 months following the date of SunPower delivery. If delivery cannot be verified, manufacture date will be used. Purchase date by end user. Date of purchase by end user. The date of installation OR ninety (90) days after delivery by Canadian Solar to the distributor (prior to being deployed to a site), whichever date is earlier.
Power Warranty Production Profile

(see Power Warranty section below)

95% for years 0-5, <=0.4% per year for years 6-25, min 87% at year 25 97% for year 1, then <=0.26% from years 2-25, min 90.76% output at year 25. 95% for years 0-5, <=0.4% per year for years 6-25, min 87% at year 25 97.5% for years 1, <=0.7% per year for years 2-25, min 80.7% at year 25
Power Warranty Conditions STC** STC** STC** STC**
Power Warranty Threshold Any power underproduction based on warrantied output in the year of measurement, as determined at SunPower’s discretion. Power underproduction greater than 3% of warrantied output in the year of measurement, at Panasonic’s discretion. Power underproduction greater than 3% of warrantied output in the year of measurement, at LG’s discretion. Power underproduction greater than the warrantied output taking testing equipment uncertainty into consideration, at Canadian Solar’s discretion.
Workmanship Warranty Thresholds Not Listed. Not Listed. Not Listed. Proof of at least one of the following: 1) loss of mechanical integrity/stability 2) loss of integrity of module’s glass, provided no evidence of localized impact / external force 3) failure of the cable and connector plug.
Warranty Action One of the following at SunPower’s discretion: 1) repair the part 2) replace the part 3) refund the original purchase price subject to some proration. One of the following at Panasonic’s discretion: 1) repair or replace with new or refurbished product 2) provide additional new or refurbished product to restore deficient output 3) refund the original purchase price to customer One of the following at LG’s discretion: 1) repair the module 2) supplement deficient power with additional module(s) 3) replace the module(s) 4) refund a prorated amount based on the current module market price and the difference between the guaranteed output and the actual output. One of the following at Canadian Solar’s discretion: 1) repair or replace with new or refurbished product 2) provide additional products to make up the wattage loss 3) provide appropriate residual market value of the product(s) as compensation.
Notable Limits Warranty valid for only 12 years if mounted on a mobile platform. Contact with salt water (at SunPower’s discretion). Movement from original installation location. Loss of product serial number, damage from sound or vibration, improper usage, improper installation, abuse, acts of god, man-made disasters, power surges, power failures. Environmental pollution, does not apply to marine or mobile install, loss of product serial number, damage from sound or vibration, improper usage, improper installation, abuse, acts of god, man-made disasters, power surges, power failures. Environmental pollution, does not apply to marine or mobile install, loss of product serial number, damage from sound or vibration, improper usage, improper installation, abuse, acts of god, man-made disasters. Environmental pollution, marine or mobile install, loss of product serial number, damage from sound or vibration, improper usage, improper installation, improper design, abuse, acts of god, man-made disasters.
Labor Warranty Yes
Covered If installed by an authorized SunPower installer, warranty covers: (i) reasonable and customary transportation costs for return of the PV Modules; (ii) reshipment of any repaired or replaced PV Modules; and (iii) costs associated with installation, removal or reinstallation of the PV Modules.
Yes
Labor warranty for recognized installation partners:  PANASONIC will cover reasonable shipment and labor costs associated with installation, removal or reinstallation of Product only at preapproved rates. (EcoMen Solar is recognized)
Yes
Cover up to $350 for the first truck roll, and $100 for a second.
Extremely Limited
Only if Canadian Solar decides to repair faulty products. However, even in that case, expenses for product removal, installation, or reinstallation are not covered.
Notable Stipulations Installation was performed by a SunPower authorized entity. Repairs must be performed by a SunPower authorized entity. Upon receipt of a claim, SunPower may require additional information regarding the claim, which may include, without limitation, applicable warranty registration information, proof of purchase and/or delivery, installation, serial and model numbers, and evidence regarding the basis of claim. Requires evidence of purchase and proof of installation by qualified persons. Product must be at original installation location. Any such assertion of claims must be accompanied by the original sales receipt as the proof of purchase and time of purchase of LG Module(s). The assertion of the claim must occur within thirty (30) days from the date that the claim is identified. The return of Module(s) may only occur after the written authorization of LG has been given. Product must be at original installation location. Claims require serial numbers, purchasing invoices and proofs, and must be within the applicable warranty period. Product must be at original installation location.
Claim Process 1) Notify an Authorized SunPower Installer 2) Contact SunPower directly. 1) Contact original installer who sold the product 2) Contact an authorized Panasonic representative 3) Contact Panasonic directly in writing. 1) Notify an authorized LG representative 2) Contact LG directly in writing. Owner submits claim in writing with supporting information to Canadian Solar
Shipping – new part Yes Yes Yes Yes
Shipping – old part Yes Yes Yes Yes
Transferability Yes
If previous owner notifies SunPower of ownership transfer within 90 days of the transfer and product remains at its original installation location.
Yes
As long as product stays at its original installation location, and proof of ownership succession exists.
Yes
As long as product stays at its original installation location.
Yes
As long as Canadian Solar is informed of the transaction and the product remains at the original installation location. The original PO Number the distributor bought the modules with, along with information about the inverter(s).
Documentation https://us.sunpower.com/solar-resources/sunpower-x-series-and-e-series-residential-dc-pv-module-limited-warranty/ ftp://ftp.panasonic.com/solar/warranty/hit_limited_warranty_for_usa_160509_warranty.pdf https://www.lg.com/us/business/download/resources/BT00002151/BT00002151_2573.pdf https://www.canadiansolar.com/downloads/warranties/en/Canadian_Solar-PV_Module_Warranty-en.pdf

 

Power Warranties – How Do They Work?

Power warranties stipulate what module power output can be expected relative to the original nameplate rating of the module. Because modules become less efficient as they age, power warranties are generally mathematical definitions from which an output percentage can be calculated. If the definition states that in year 10 the output percentage of a 300W at STC** module is 93%, then that module is expected to produce 279W.

Now, if that module is tested and found to produce less than 279W, then action may be warranted. May is operative because most module manufacturers also stipulate some kind of power warranty threshold. Usually this threshold takes into account measurement uncertainty introduced by the test equipment. Generally this uncertainty is cited as a percentage (for example, a company citing a 3% uncertainty would require the module to be measured as producing 3% less than 279W, or 270.6W). However, in some cases the threshold is left as a matter of pure discretion.

Take a quick glance at the Power Warranty Production Profile row in the Warranty Comparison Table shown above. Those are the power warranty definitions. The Power Warranty Profile Comparison table below expands those definitions into the actual percentages for the 25 years they apply to. Also, we’ve plotted this data to provide a visual representation.

Obviously the less quickly the module degrades, the more energy it will have produced up to that point in time. That said, its important to keep these factors in perspective relative to the price of the module. Additional costs paid for premium products on account that they degrade more slowly may never be recovered by the additional production resulting from slowed degradation.

Power Warranty Profile Comparison

Brand SunPower Panasonic LG Canadian Solar
Year 1 98.000% 97.000% 95.000% 97.500%
Year 2 97.750% 96.740% 95.000% 96.800%
Year 3 97.500% 96.480% 95.000% 96.100%
Year 4 97.250% 96.220% 95.000% 95.400%
Year 5 97.000% 95.960% 95.000% 94.700%
Year 6 96.750% 95.700% 94.600% 94.000%
Year 7 96.500% 95.440% 94.200% 93.300%
Year 8 96.250% 95.180% 93.800% 92.600%
Year 9 96.000% 94.920% 93.400% 91.900%
Year 10 95.750% 94.660% 93.000% 91.200%
Year 11 95.500% 94.400% 92.600% 90.500%
Year 12 95.250% 94.140% 92.200% 89.800%
Year 13 95.000% 93.880% 91.800% 89.100%
Year 14 94.750% 93.620% 91.400% 88.400%
Year 15 94.500% 93.360% 91.000% 87.700%
Year 16 94.250% 93.100% 90.600% 87.000%
Year 17 94.000% 92.840% 90.200% 86.300%
Year 18 93.750% 92.580% 89.800% 85.600%
Year 19 93.500% 92.320% 89.400% 84.900%
Year 20 93.250% 92.060% 89.000% 84.200%
Year 21 93.000% 91.800% 88.600% 83.500%
Year 22 92.750% 91.540% 88.200% 82.800%
Year 23 92.500% 91.280% 87.800% 82.100%
Year 24 92.250% 91.020% 87.400% 81.400%
Year 25 92.000% 90.760% 87.000% 80.700%


Notes(s):
*Modules have a 15 year default workmanship warranty which goes to 25 upon registration at http://www.panasonicusahitwarranty.com/

**STC (Standard Test Conditions) is defined as Irradiance 1000W/m2, Cell temperature 25 °C, Air Mass 1.5g.

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