Why are my solar panels underperforming?
Solar panel underperformance is more common than most owners realise. Over time, every system loses some efficiency — but the question is how much, and whether the loss is within normal range or a sign of a fixable problem. Here are the most common causes of solar energy loss and what you can do about each one.
Related issues
Natural panel degradation
All solar panels lose efficiency over time at roughly 0.5–0.8% per year. Accelerated in extreme heat or poorly manufactured panels.
Self-check tip:
Compare current annual production to your system's first-year output. A decline beyond 1% per year may indicate accelerated degradation.
Cell hotspots
Localised overheating in individual cells caused by micro-cracks, shading, or manufacturing defects. Best detected via thermal imaging.
Panel soiling
Dust, pollen, bird droppings, or debris accumulation reducing light absorption. More severe in arid or agricultural areas.
Self-check tip:
Visually inspect panels from ground level. If you can see a visible film or debris, cleaning may restore 2–7% production.
Inverter efficiency loss
Degradation or malfunction in the inverter reducing DC-to-AC conversion efficiency. Often indicated by error codes or unexpected shutdowns.
Self-check tip:
Check your inverter display for error codes or red/amber warning lights. Compare current output to the inverter's rated capacity.
Is your system affected?
Use our free Solar Loss Checker to estimate how much energy your system may be losing.
Check my systemBased on conservative solar performance modelling and published degradation data
Updated April 2026 · Structured performance modelling
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