Solar Warranties: Product, Performance, Workmanship

A solar installation carries at least three warranties from at least two parties, covering different things and failing in different ways. Knowing which is which is what lets you evaluate a proposal properly.

The three warranties

Note that the installer's warranty is the one covering your roof, and it's the one with the most variation between companies.

What does a solar product warranty cover?

Covers manufacturing defects — delamination, junction box failure, frame problems, seal failure.

Questions worth asking:

• How long? Terms vary between manufacturers.
• Does it cover labor and shipping? A replacement panel is only part of the cost; getting someone on the roof to swap it is the rest. Many product warranties cover the panel only.
• Who administers the claim? Usually you go through the installer, which is another reason installer longevity matters.

What does a solar performance warranty guarantee?

Guarantees a minimum retained output over time, typically expressed as a first-year figure plus an annual degradation rate, ending at a guaranteed percentage at the end of the term.

Two useful points:

The end-of-term guaranteed output is the most comparable single number between panels. It folds the degradation rate and the term length into one figure you can put side by side.

Claiming is harder than it sounds. You have to demonstrate that a panel is below the warranted curve, which requires production data — and separating a genuinely underperforming panel from shading, soiling, an inverter issue or a bad string is not trivial.

That's a practical argument for module-level monitoring: without per-panel data, proving a performance claim is difficult. See solar panel monitoring explained and why is my solar production low.

See also how long do solar panels last.

What is a solar workmanship warranty?

This is the installer's warranty on their own work, and it's where the real risk sits.

Why it matters most:

• Installation problems are more common than panel defects. Panels are mass-produced under tight quality control; installations are done by people on your specific roof.
• Roof penetrations are the highest-consequence failure. A leak at a mounting point damages your house, not just your system, and it may not show up for years.
• It covers the things that actually go wrong — flashing, wiring, mounting, conduit, labeling.

The terms vary enormously. Some installers offer coverage measured in decades; others offer a couple of years. That difference is one of the more meaningful distinctions between two otherwise similar proposals.

Ask specifically:

• How long, and what exactly is covered?
• Does it cover roof leaks at penetrations, and for how long?
• Does it cover labor for warranty replacements of panels and inverters?
• Is it transferable if I sell?
• Is it backed by anything if the company ceases trading?

What happens if your solar installer goes out of business?

Here's the uncomfortable structural issue with solar warranties.

A 25-year performance warranty is administered through your installer. A 25-year workmanship warranty is only worth something if the installer exists in 25 years.

The residential solar industry has seen substantial company turnover. Which means:

• Company stability matters as much as warranty length. A 10-year warranty from a firm that will exist is worth more than a 25-year warranty from one that won't.
• Long-established local installers have a track record you can check.
• Ask what happens if they cease trading — some warranties are backed by third parties or insurance.
• Keep your own documentation so a different company can take over service.

See choosing a solar installer.

The inverter warranty

Worth separating out, because the inverter is the component most likely to need replacement during the system's life.

• String inverter warranties are typically shorter than panel warranties
• Microinverter warranties are often longer, sometimes matching panel terms
• Extended warranties are frequently available at purchase

Because inverter replacement is a realistic mid-life expense, it belongs in your long-run economics. See string inverters vs microinverters and how solar payback works.

What do solar warranties not cover?

Common exclusions:

• Damage from severe weather — that's your homeowner's insurance. See solar panel hail and storm damage.
• Damage from improper cleaning — see how to clean solar panels
• Modification by others, which can void coverage
• Production shortfalls from shading that developed after installation — a growing tree is your problem
• Roof failure unrelated to the mounts
• Removal and reinstallation for roof replacement — a real cost worth planning for. See solar panels and roof replacement.

That last one catches people. If your roof needs replacing during the system's life, taking panels off and putting them back is an expense nobody's warranty covers.

Leases, PPAs and third-party ownership

If you don't own the system, the warranty picture changes entirely — the owner is responsible for maintenance and performance, and your obligations are contractual rather than warranty-based.

Read what happens at end of term, on sale of the house, and if the provider is acquired. See solar loan vs lease vs PPA.

A checklist for comparing proposals

• Panel product warranty term, and whether labor is included
• Panel performance warranty — guaranteed output at end of term
• Inverter warranty term, and extension options
• Workmanship warranty term, and whether roof leaks are covered
• Whether labor for warranty replacements is covered
• Transferability of each on sale
• What backs the workmanship warranty if the installer ceases trading
• Installer's years in business and local track record

The bottom line

Three warranties from two parties: product and performance from the panel manufacturer, workmanship from the installer, plus a separate inverter warranty. The workmanship one matters most, because installation problems — especially roof penetrations — are more common than panel defects and damage your house rather than just your output. And every one of them depends on the issuing company still existing, which makes installer stability part of the warranty evaluation rather than separate from it.

Model long-run value with the solar panel payback calculator, estimate output with the solar output calculator, or read choosing a solar installer.