LONGi warranty review

We read LONGi’s warranty so you don’t have to

Let’s face it – warranties aren’t the easiest (or most gripping) documents to read. There are often a lot of details and fine print included that can be hard to digest, leaving many to wonder: what does the warranty actually cover? Am I vulnerable? Anything I might be missing?

To make it as easy as possible, we’ve read warranty documents for the top solar equipment manufacturers–and talked to them to confirm what is and isn’t included–and plan to point out the most important aspects of each in a series of articles. In this article, we’ll review the warranty of one of the most bankable companies manufacturing solar panels for homes: LONGi


Highlights of LONGi’s warranty


  • Includes a 12-year limited product warranty and a 30-year limited performance warranty. 
  • Covers replacements, repairs and/or refunds up to the residual value of your solar panel at no cost to you – but doesn’t cover labor or other associated costs.
  • LONGi is a highly bankable, BNEF Tier 1 company.
  • Visit the EnergySage Marketplace to compare solar options from local installers.

Quick overview: LONGi’s history and warranty

Founded in 2000, LONGi Green Energy Technology Co., Ltd. (LONGi) works under the mission “to make the best of solar energy to build a green world”. LONGi is known for their high efficiency mono-crystalline solar cells and modules and as a leader in the development of solar power projects. 

Importantly, LONGi is a vertically-integrated company, manufacturing most of the components used in both of their product lines: their high-efficiency single-glass modules and high-efficiency dual-glass modules. They have strong control over the solar supply chain, making them extremely influential and bankable in the global solar industry. 

LONGi’s solar panel warranty at a glance 

CATEGORYLONGi’s COVERAGEINDUSTRY STANDARD
Product12 years10 years
PowerHigh-efficiency single-glass modules: 84.8% at year 25
High-efficiency dual-glass modules: 87.2% at year 25, 85% at year 30
80% at year 25
Labor costsNoNo
WorkmanshipNoNo
Shipping of partsYesNo
Extended warranty offeringNoNo

LONGi’s product warranty

Also known as a material warranty, a solar panel manufacturer’s product warranty covers the integrity of the equipment itself – if your solar panels have a defect, mechanical issue, or experience unreasonable wear and tear, that should be covered by your product warranty. 

If there’s a defect with your solar panel, it’s typically apparent “out-of-the-box”. In other words, you or your installer should be able to tell that something is amiss and fix the problem immediately–often before the panel even makes it to your roof. Regardless, it’s good to consider products with longer warranties for the peace of mind it provides.

LONGi includes a 12-year limited product warranty for all of their solar panels. It’s important to note that LONGi will decide how they compensate you for these solar panels, whether it be through a replacement, repair, or refund up to the current residual value of your panels. 

LONGi’s power warranty

Like every other type of electronic, the performance of your solar panels will degrade over time: fortunately, solar panel manufacturers offer a power (or performance) warranty for their products. Power warranties help protect you against atypical degradation of your solar panels, ensuring that the output of your panels won’t fall below a certain level after a set period of time. Different types of solar panel technologies degrade at different rates. Generally speaking, the highest quality solar panels offer long power warranties (25 years or more) that guarantee at least 80 percent of the original output by the end of the warranty term.

LONGi provides a 25-year power warranty for their single-glass modules and a 30-year power warranty for their bifacial dual-glass modules. LONGi guarantees that their products will still produce at least 85% and 84.8% of their original output by the end of the warranty term for their dual glass and single glass models, respectively. Here’s a breakdown of LONGi’s warrantied degradation by product line:

High-efficiency single-glass modules

  • 98% output at the end of year 1
  • No more than 0.55% degradation from years 2-25
  • Power output of 84.8% by year 25

High efficiency dual-glass modules

  • 98% output at the end of year 1
  • No more than 0.45 % degradation from years 2-25
  • Power output of 87.5% by year 25
  • Power output of 85% by year 30

You can review and compare LONGi solar panels in the EnergySage Buyer’s Guide.

Does LONGi offer extended warranties?

Need a little extra protection for peace of mind? Many solar panel manufacturers offer extended warranties for their products. Depending on the company and the product, extended warranties can come at an extra cost, or only be available for certain installers who have been certified and endorsed by the manufacturer.

LONGi does not currently offer extended warranties. 

LONGi’s workmanship warranty

More often than not, solar installers are the sole party responsible for providing workmanship warranties for a solar installation. However, some manufacturers offer additional protection by tacking on their own workmanship warranty for a limited number of certified installers in their network. If your solar panel warranty doesn’t cover workmanship, this cost (and whether you’re responsible for it) will typically fall under the umbrella of your installer’s workmanship warranty. Be aware that workmanship warranties vary from one installation company to the next, so remember to read your installer’s workmanship warranty thoroughly before signing any contract!

LONGi does not currently offer a workmanship warranty to their distributors or direct customers. You can learn more about manufacturer endorsements and how they impact installer warranty offerings in this article

How to make a warranty claim with LONGi: shipping & labor costs

Ideally, your solar panel system will continue operating smoothly for 25+ years, and you never have to worry about LONGi’s warranty. However, if you experience any defects or performance issues with your solar panel system, LONGi will be there to help.

If you notice an issue with your system, your first phone call should be to your original installer: having designed and installed your system, they are the most equipped to diagnose (and fix!) any potential issue. If your installer determines that you need to replace a piece of equipment–like a solar panel– they can file a warranty claim on the LONGi website or through an email within 30 days of the problem arising. Your installer can also reach out directly to LONGi’s distributors, which will shorten the claim processing team. 

LONGi requires you to submit some additional documentation, such as photo evidence and the serial number of the model. Depending on the situation, LONGi may request that you ship the defective parts to the factory, or will send a representative to assess the damage. If, for whatever reason, LONGi cannot fix or replace your panel, they will compensate you for reduced solar panel performance and pay you the residual value.

Unfortunately, solar installers can go out of business, and you may find yourself in a position where you can no longer call the business that installed your system for help. In this case, you can work with LONGi directly to make a claim. In this situation, you are advised to contact LONGi through email or a form available on their website.

Most solar panel manufacturers do not cover any labor costs associated with replacing or repairing their products, including LONGi. However, in most cases, they will cover the shipping of repaired or replaced solar panels, as long as it’s determined that they are covered under warranty – talk to your installer to determine if there are any additional fees that could be associated with shipping LONGi panels, which would be stipulated under the original contractual shipping terms.

Limitations and exceptions to LONGi’s warranty

Every warranty has its exceptions – LONGi’s is no different. Warranty limitations aren’t meant to make it harder for you to take advantage of the offering; companies simply try to protect themselves from unjust or unreasonable claims. 

Here are a few things that aren’t covered in your LONGi warranty:

  • Defects or damage caused by extreme weather events (i.e. lightning, hurricanes, tornados, earthquakes, fires, flooding).
  • Damage caused by unapproved maintenance, repair or alteration. 
  • Installation of LONGi products over non-approved roof decks.
  • Damage from any structural changes or additions made to your roof after your solar panel system was installed.
  • Cosmetic defects, dents, or markings that do not impact the performance of the products.

Other warranty considerations, and how LONGi stacks up

  • Bankability: LONGi is a vertically-integrated, highly bankable company; in fact, they are listed as a Tier 1 (most bankable) company by BNEF. 
  • Escrows/insurance policies: LONGi doesn’t provide information on if they have an insurance policy or an escrow that ensures their warranty will be upheld if they go out of business.
  • Customer reviews: Another critical aspect of understanding a manufacturer’s warranty offering is investigating how their customers feel about their equipment and the services that they provide. Any warranty can look promising on paper, but how the installer or manufacturer performs when honoring their warranty is also critically important. If you are interested in reading LONG’s reviews, you can do so here

Finding the right solar panels for you

Finding the right solar panel system for your home means comparing multiple quotes from solar installers. Using the EnergySage Marketplace, you can find local solar installers near you, and make easy side-by-side comparisons of all your solar options, including equipment. By shopping around first, you can find the right option at the right price – warranties and all. If you have a preference for one type of equipment over another–LONGi or otherwise–simply note it in your account when you sign up so installers can quote you accordingly.


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About Ananyaa Mehra

Ananyaa Mehra is a rising junior at Tufts University pursuing a bachelors of science in Environmental Studies as well as a minor in entrepreneurship. On campus, she is involved with the Energy club, sustainability council, and helps plan the annual Tufts Energy Conference. She is passionate about and has expertise in electrification, renewable energy, and green technology, with a focus on policy and equity. In her free time, she loves spending time in the ocean, trying new coffee shops, and traveling.

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