A 25-year warranty sounds like peace of mind. But a warranty is a promise, and a promise is only as good as the company making it. If that company stops trading, the warranty can go with it.
Three warranties, three different promises
A commercial solar or battery system usually comes with three kinds of cover:
- Product warranties from the manufacturer, covering defects in panels, inverters and batteries. Panel product warranties commonly run 12 to 25 years; inverters are often 5 to 10.
- Performance warranties, also from the manufacturer, promising panels will still produce a set share of their rated output after 25 years or more.
- A workmanship warranty from the installer, covering the installation itself. This is usually much shorter.
Each one depends on a different company still being around when you need it.
When a manufacturer disappears
Solar manufacturing is fiercely competitive, and plenty of well-known brands have left the market. If a manufacturer stops trading and its warranties aren't backed by insurance, a claim usually has nowhere to go.
Some manufacturers back their warranties with a third-party insurance policy that pays out if they can't. That's worth having, but check who the insurer is and what the policy actually covers: replacement equipment only, or labour and access too?
When the installer goes bust
A workmanship warranty normally ends when the installer does, unless it's protected by an insurance-backed guarantee (IBG), where an insurer takes on the liability if the installer stops trading.
IBGs are common on homes but less so on commercial projects, so other protections matter more: retention money held back until the system has proved itself, performance bonds or parent company guarantees, and making sure manufacturer warranties are registered in your name rather than the installer's.
What we check before you sign
- The manufacturer's financial strength and track record in the UK, and whether its warranties are insurance-backed.
- That every warranty is registered to you, and transfers if you sell the building.
- Whether the workmanship warranty has an IBG or equivalent security behind it.
- Exactly what happens in each scenario: the manufacturer goes, the installer goes, or both.
- Who you call on day one if something fails.
It takes an hour to get this right before you sign, and it can save years of arguments afterwards.