Understanding warranties and guarantees
Commercial solar contracts typically include manufacturer warranties for panels and inverters, plus installer workmanship warranties and sometimes performance guarantees. Manufacturer warranties cover product defects and performance degradation, while performance guarantees commit to a minimum annual energy output or system availability.
Common warranty types:
- Product warranty: Covers defects in panels or inverters (often 10–25 years)
- Performance warranty: Guarantees a percentage of rated output over time (e.g., 80% after 25 years)
- Workmanship warranty: Installer’s guarantee for labor and installation quality (often 1–10 years)
- O&M/availability guarantees: May guarantee system uptime or annual production targets
What to look for in contracts
- Clear remedies for underperformance (repairs, payments, or make-good periods)
- Transferability if property is sold
- Exclusions and maintenance requirements to keep warranties valid
Carefully review warranty durations, coverage limits, and claim procedures. Strong contractual protections and reputable vendors reduce long-term risk and ensure reliable outcomes.