Is your solar inverter losing efficiency?
Your inverter converts DC power from your panels into usable AC electricity. When it degrades or malfunctions, your entire system's output drops — sometimes by 10–25%. Here's how to spot inverter issues early and what to do about them.
Symptoms to watch for
Signs that this issue may be affecting your system
Inverter efficiency loss
ModerateDegradation or malfunction in the inverter reducing DC-to-AC conversion efficiency. Often indicated by error codes or unexpected shutdowns.
What you can check yourself
Actions you can take today without professional help
Inverter efficiency loss
Check your inverter display for error codes or red/amber warning lights. Compare current output to the inverter's rated capacity.
When to get a professional inspection
Signs you need professional help
Expected inspection costs
Drone thermal audit
Most comprehensive option
Handheld thermal scan
Best for smaller systems
Electrical inspection
Inverter and wiring only
Find inspection providers
Browse providers — US · UK · Australia · SpainIs your system affected?
Use our free Solar Loss Checker to get a personalised diagnosis with an action plan.
Based on conservative solar performance modelling and published degradation data
Updated June 2026 · Structured performance modelling
How we calculate →More guides
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Frequently asked questions
How much performance loss is typical for this solar problem?+
Inverter efficiency loss typically causes 5–25% output loss on residential solar systems, depending on severity, panel count affected, and how long the defect has been present.
Can I detect this issue without a professional inspection?+
Some signs (visible discolouration, hot panels on a clear day, inverter error codes, year-on-year kWh drop > 8%) are observable from monitoring data. For confirmation, a thermal imaging inspection — drone or handheld FLIR — is the gold standard and costs $299–$549 for a residential system.
Is this covered under my panel or inverter warranty?+
Most tier-1 panel warranties cover defects causing performance below 80–85% of nameplate within 25 years, and inverter warranties run 10–12 years. Claims almost always require third-party diagnostic evidence (thermal images, IV-curve traces, or written performance reports).
How fast does this defect get worse if I ignore it?+
Untreated, inverter efficiency loss can compound — a single hot cell can degrade neighbouring cells through reverse bias, and a failing optimiser or inverter often cascades across strings. Typical degradation acceleration is 2–4× normal once a fault is present.
What does a thermal inspection cost to confirm this?+
A residential thermal solar inspection in the US costs $299–$549, UK £249–£449, and Australia AU$399–AU$699. Drone-based audits are usually at the lower end and complete a 10 kW array in under 20 minutes.
Should I repair, replace, or claim warranty?+
Rule of thumb: if defect-affected panels represent < 10% of array output, repair (e.g. bypass diode replacement, junction box rework). If 10–25% and within warranty period, file a claim. If > 25% and out of warranty, model the payback of partial re-power vs full replacement against current $/W pricing.