How long solar panels last, and what the warranty actually covers

A solar array is a twenty five year asset bolted to your roof. That is long enough that the warranty paperwork is a real part of what you are buying, and long enough that it is worth knowing which parts actually fail.

Modules outlive their warranty, usually

A solar module has no moving parts. What it does is degrade slowly, producing a little less each year as the cells age.

Manufacturers publish a production warranty on top of the workmanship one: a guarantee that the module will still produce at least some stated percentage of its rated output after a given number of years. Twenty five years at somewhere around 85 to 90% of nameplate is a common shape for a quality module today.

In practice, well-made modules frequently outperform that curve and keep producing past the warranty period at reduced output. The failure modes that actually take a module out early are physical: impact damage, water ingress through a failed seal, or a manufacturing defect that shows up in the first years rather than the twentieth.

Inverters are what fail

The inverter converts DC from your modules into AC your house can use, and it is doing real electrical work every day. It is the component most likely to need replacement inside the life of the system.

This is the main argument for microinverters, which put a small inverter under each module rather than running the whole array through one central box:

• A failure takes out one module’s production, not the entire array.
• You get per-module monitoring, so you know exactly which unit failed rather than diagnosing a system-level shortfall.
• Warranty terms on microinverters are typically much longer than on string inverters.
• Shade on one module does not drag down a whole string.

String inverters are cheaper and are the right answer on some projects, particularly larger unshaded commercial arrays. The tradeoff is that the single point of failure is genuinely single.

The three warranties, and which one matters

People think of “the warranty” as one thing. It is three, from three different parties.

Warranty	Who provides it	What it covers
Module warranty	Module manufacturer	Defects, plus a production guarantee over ~25 years
Inverter warranty	Inverter manufacturer	The inverter unit itself
Workmanship warranty	Your installer	The installation. Mounting, flashing, wiring, penetrations, labor

The first two are backed by large companies and are relatively predictable. The third is the one that varies, and it is the one that matters most in practice, because the most common expensive problem with a solar array is not a dead module. It is a roof penetration that was not flashed properly and is now a leak.

A manufacturer warranty also does not usually pay for the labor to swap the part. If a microinverter fails in year nine, the manufacturer sends a replacement unit. Somebody still has to get on your roof, pull the module, and install it. Who pays for that, and who shows up, is a workmanship warranty question.

Questions worth asking any installer

• What is the workmanship warranty, in years, in writing?
• Does it cover the labor to replace a part that fails under manufacturer warranty?
• Does it cover roof penetrations and leaks specifically?
• Who honors it if you are not in business? Is the obligation with you, a parent company, or a third party?
• Do you subcontract the install, and does the warranty follow the sub or you?

We are a small local company, which cuts both ways and we would rather say so plainly. We are not a national brand with a corporate warranty department. We are also twenty minutes away, the owners are on your project, and we are not planning to leave West Michigan.

The roof underneath

The single best thing you can do for the twenty five year life of your array is to not put it on a roof with five years left. Pulling and re-setting an array to reroof underneath it is real money.

We check roof age and condition before we quote. If we think the roof should be replaced first, we will tell you that, even though it means the project waits.