Clear answer
Clear answer, explained.
Panels are typically warranted at a minimum output level — commonly 80–85% of nameplate capacity — at year 30. Well-maintained systems operating in Ontario conditions regularly achieve this.
Inverters have a shorter service life — typically 12–15 years for string inverters. Inverter replacement is a planned maintenance event within the 30-year financial model, not a system failure. Most systems will require at least one inverter replacement across their operating life.
Regular inspection and proactive maintenance are what close the gap between designed lifespan and actual operating performance.
Key points
What this means in practice.
- Commercial solar systems are designed and financially modelled for a 30-year operating life
- Panels are typically warranted at 80–85% of nameplate capacity at year 30
- Well-maintained systems operating in Ontario conditions regularly achieve the 30-year panel warranty threshold
- String inverters have a shorter service life — typically 12–15 years
- Inverter replacement is a planned maintenance event in the 30-year financial model, not a system failure
- Regular inspection and proactive maintenance close the gap between designed lifespan and actual operating performance
When this applies
Best-fit environments.
- You are evaluating the long-term financial case for commercial solar and need to understand the system lifespan assumptions
- Your CFO has asked what happens to the system at year 10 or 15 and whether there are significant capital costs ahead
- You are planning a maintenance programme and want to understand when inverter replacement should be scheduled
- You have acquired an existing solar system and want to understand where it sits in its operating life
Q·01
