Warranties are like spare tires: you never think about them until you really, really need them. But in the case of a commercial solar panel warranty, it’s definitely worth your time to dig into the details of what’s covered, for how long, and how likely it is you’ll use it—before making your purchase decision.

What makes a good solar panel? Obviously, the warranty is only one of several criteria to keep in mind as you evaluate your options. But it’s certainly one of the most important. After all, understanding the long-term financial impact of your warranty coverage will help your business be better prepared for what lies ahead—and minimize the likelihood of pricey surprises.

• A tale of two solar panel warranties: product and power
• Knowing what’s covered, and for how long
• Uncovering the hidden costs of warranty service

A tale of two solar panel warranties: product and power

Generally speaking, commercial solar panel manufacturers offer two types of warranty: product and power. But there’s another critical warranty component that may or may not be included—the services you’re provided anytime a panel fails. While these services are not usually called out as a warranty per se, it’s vital to know what the panel manufacturer will cover in the event of a claim. We’ll cover this in more detail below.

To start, a solar panel product warranty covers just that: any defects in materials or workmanship. If a panel suddenly stops working after a few months because of a flaw in its solder joint, for example, your product warranty will most likely cover its repair or replacement.

Then there’s the solar panel power warranty—sometimes referred to as the performance warranty. Over time, the power output of all solar panels diminishes or “degrades”. Knowing this degradation rate (which any manufacturer should be able to provide) will give you clear sense of the minimum amount of power you’ll be guaranteed for the first 5, 10 and 20 years of your panels’ life. Then, if a panel’s output is lower than promised, your power warranty should cover the cost of its replacement.

Knowing what’s covered, and for how long

Most solar panel product warranties last from 10 to 12 years, while power warranties are longer—usually 25 years. This difference in warranty lengths is an important point, and also where it gets a little confusing. So, you’ll have to be a bit more vigilant about your research and warranty comparisons.

You might think a panel’s power warranty covers any situation where its performance or output is compromised. But be sure to take a closer look. Most panel manufacturers focus solely on their power warranty, because it often appears to guarantee a working panel for an even greater length of time than their product warranty. However, many of these power warranties are not supported by their accompanying product warranties.

For many solar manufacturers, only their panels’ product warranty covers failure due to product defects or workmanship—and their power warranty doesn’t mention defects at all. So, if a defect happens after your product warranty expires, you’ll likely be out of luck.

In addition to knowing what’s covered in your commercial solar panel warranty, it’s also important to know what isn’t. Some warranties, for instance, exclude constant shade, exposure to salt or seaside environments. They may also exclude microcracks in cells (a symptom of power loss) or damage incurred during transport. Some manufacturers may even exclude warranty coverage if you lack the original paper receipt or annual cleaning records—or impose fees if no defect is found.

Uncovering the hidden costs of warranty services

As we’ve seen, most solar manufacturers have product and power warranties of varying lengths of time. But without the proper service coverage, relying on these warranties alone can result in substantial unexpected costs for your business.

Here’s why. Say one of your solar panels malfunctions. It has to be removed and a new panel is ordered, shipped and then installed. Who’s going to pay for those services? You? The manufacturer? You might think they’re covered, but oftentimes they’re not. It pays to make sure.

These are questions you should be prepared to ask and account for in your financial projections and solar panel warranty comparisons. It’s also important to consider how long panel repair or replacement services typically take, so you can factor that downtime into your energy costs.

SUMMARY

What are the key components of a commercial solar panel warranty—and how do warranties among manufacturers compare? The devil, as they say, is in the details. But now you know enough to contrast and compare your options. Understanding the structure of the warranty, how its product and power components compare and what you’re likely to pay in repair/replacement costs and the services that go with it are all critical to making the right long-term solar panel investment decisions for your organization.

This post originally appeared on the SunPower Business Feed.