Quotes, contracts and finance

What warranties come with a solar system?

The short answer

At least three, from different parties: a product warranty on the panels from the manufacturer, a separate performance warranty on their output, a manufacturer warranty on the inverter which is usually much shorter, and the installer's own workmanship warranty. The last one covers the failures most likely to affect you, and it is the only one written by the company standing in front of you.

The four documents

Panel product warranty: the panel as a physical object, usually long, from the manufacturer.
Panel performance warranty: that output will not degrade below a stated proportion of the original by a stated year. Separate from the product warranty and frequently confused with it.
Inverter warranty: from the inverter manufacturer, commonly much shorter than the panel warranty, which is why an inverter replacement partway through a system's life is a normal expectation rather than a surprise.
Workmanship warranty: the installer's own, covering the installation, including the roof penetrations. Its terms are whatever the installer wrote down.

What to check in the workmanship warranty

Length, and whether it covers labour as well as parts.
Whether roof penetrations and leaks are covered, explicitly.
Whether it covers the labour of a manufacturer warranty claim — a free replacement panel still has to be taken off the roof and put back.
What voids it, including work by others on the roof.
Whether it transfers when the house is sold, and on what terms.

A long panel warranty from a manufacturer on another continent is worth what the process of claiming it is worth. Ask who handles the claim, who pays for the labour, and what happens if the manufacturer no longer exists.

Also asked

What if the manufacturer goes out of business?

The warranty is generally worth what the company behind it is worth, which is why manufacturer longevity is a real consideration and why the installer's workmanship warranty and their willingness to handle claims matters. Keep every document and every model number; a future service company will need them.

The long version

After the installation

Permission to operate, monitoring, what a workmanship warranty covers, and what happens if your installer disappears.

General information about solar and about hiring, not advice about your roof or your tax affairs. Incentives, net metering and contractor licensing are set federally, by state, and by your utility, and all of them change. The authority that publishes the rule is the current answer.